style: Make "empty timeline" warning only warn in debug mode

perf: Delayed drop is probably unnecessary
feat: Add compile flag to instantly drop mutex for A/B testing
2026-04-03 00:25:45 +00:00 · 2026-02-23 21:36:13 +00:00 · 2026-02-23 21:18:46 +00:00 · 2026-02-23 20:58:22 +00:00 · 2026-02-23 20:45:44 +00:00 · 2026-02-23 17:59:13 +00:00
43 changed files with 856 additions and 415 deletions
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -72,15 +72,6 @@ dependencies = [
 "alloc-no-stdlib",
 ]

-[[package]]
-name = "android_system_properties"
-version = "0.1.5"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "819e7219dbd41043ac279b19830f2efc897156490d7fd6ea916720117ee66311"
-dependencies = [
- "libc",
-]
-
 [[package]]
 name = "annotate-snippets"
 version = "0.12.12"
@@ -615,15 +606,6 @@ dependencies = [
 "generic-array",
 ]

-[[package]]
-name = "block2"
-version = "0.6.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "cdeb9d870516001442e364c5220d3574d2da8dc765554b4a617230d33fa58ef5"
-dependencies = [
- "objc2",
-]
-
 [[package]]
 name = "blurhash"
 version = "0.2.3"
@@ -813,13 +795,13 @@ dependencies = [

 [[package]]
 name = "clang-sys"
-version = "1.8.1"
+version = "1.6.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0b023947811758c97c59bf9d1c188fd619ad4718dcaa767947df1cadb14f39f4"
+checksum = "c688fc74432808e3eb684cae8830a86be1d66a2bd58e1f248ed0960a590baf6f"
 dependencies = [
 "glob",
 "libc",
- "libloading",
+ "libloading 0.7.4",
 ]

 [[package]]
@@ -1025,7 +1007,7 @@ dependencies = [
 "ipaddress",
 "itertools 0.14.0",
 "libc",
- "libloading",
+ "libloading 0.9.0",
 "lock_api",
 "log",
 "maplit",
@@ -1240,7 +1222,7 @@ dependencies = [
 [[package]]
 name = "continuwuity-admin-api"
 version = "0.1.0"
-source = "git+https://forgejo.ellis.link/continuwuation/ruwuma?rev=df6fa9a394b259c9cd3420e2b52a47847510ed86#df6fa9a394b259c9cd3420e2b52a47847510ed86"
+source = "git+https://forgejo.ellis.link/continuwuation/ruwuma?rev=e087ff15888156942ca2ffe6097d1b4c3fd27628#e087ff15888156942ca2ffe6097d1b4c3fd27628"
 dependencies = [
 "ruma-common",
 "serde",
@@ -1596,16 +1578,6 @@ dependencies = [
 "subtle",
 ]

-[[package]]
-name = "dispatch2"
-version = "0.3.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "89a09f22a6c6069a18470eb92d2298acf25463f14256d24778e1230d789a2aec"
-dependencies = [
- "bitflags",
- "objc2",
-]
-
 [[package]]
 name = "displaydoc"
 version = "0.2.5"
@@ -1629,7 +1601,7 @@ dependencies = [
 [[package]]
 name = "draupnir-antispam"
 version = "0.1.0"
-source = "git+https://forgejo.ellis.link/continuwuation/ruwuma?rev=df6fa9a394b259c9cd3420e2b52a47847510ed86#df6fa9a394b259c9cd3420e2b52a47847510ed86"
+source = "git+https://forgejo.ellis.link/continuwuation/ruwuma?rev=e087ff15888156942ca2ffe6097d1b4c3fd27628#e087ff15888156942ca2ffe6097d1b4c3fd27628"
 dependencies = [
 "ruma-common",
 "serde",
@@ -2831,9 +2803,9 @@ checksum = "7a79a3332a6609480d7d0c9eab957bca6b455b91bb84e66d19f5ff66294b85b8"

 [[package]]
 name = "libc"
-version = "0.2.182"
+version = "0.2.180"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6800badb6cb2082ffd7b6a67e6125bb39f18782f793520caee8cb8846be06112"
+checksum = "bcc35a38544a891a5f7c865aca548a982ccb3b8650a5b06d0fd33a10283c56fc"

 [[package]]
 name = "libfuzzer-sys"
@@ -2847,9 +2819,19 @@ dependencies = [

 [[package]]
 name = "libloading"
-version = "0.8.9"
+version = "0.7.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d7c4b02199fee7c5d21a5ae7d8cfa79a6ef5bb2fc834d6e9058e89c825efdc55"
+checksum = "b67380fd3b2fbe7527a606e18729d21c6f3951633d0500574c4dc22d2d638b9f"
+dependencies = [
+ "cfg-if",
+ "winapi",
+]
+
+[[package]]
+name = "libloading"
+version = "0.9.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "754ca22de805bb5744484a5b151a9e1a8e837d5dc232c2d7d8c2e3492edc8b60"
 dependencies = [
 "cfg-if",
 "windows-link",
@@ -3021,7 +3003,7 @@ checksum = "f8ca58f447f06ed17d5fc4043ce1b10dd205e060fb3ce5b979b8ed8e59ff3f79"
 [[package]]
 name = "meowlnir-antispam"
 version = "0.1.0"
-source = "git+https://forgejo.ellis.link/continuwuation/ruwuma?rev=df6fa9a394b259c9cd3420e2b52a47847510ed86#df6fa9a394b259c9cd3420e2b52a47847510ed86"
+source = "git+https://forgejo.ellis.link/continuwuation/ruwuma?rev=e087ff15888156942ca2ffe6097d1b4c3fd27628#e087ff15888156942ca2ffe6097d1b4c3fd27628"
 dependencies = [
 "ruma-common",
 "serde",
@@ -3122,9 +3104,9 @@ checksum = "650eef8c711430f1a879fdd01d4745a7deea475becfb90269c06775983bbf086"

 [[package]]
 name = "nix"
-version = "0.30.1"
+version = "0.31.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "74523f3a35e05aba87a1d978330aef40f67b0304ac79c1c00b294c9830543db6"
+checksum = "225e7cfe711e0ba79a68baeddb2982723e4235247aefce1482f2f16c27865b66"
 dependencies = [
 "bitflags",
 "cfg-if",
@@ -3278,165 +3260,6 @@ dependencies = [
 "libc",
 ]

-[[package]]
-name = "objc2"
-version = "0.6.3"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b7c2599ce0ec54857b29ce62166b0ed9b4f6f1a70ccc9a71165b6154caca8c05"
-dependencies = [
- "objc2-encode",
-]
-
-[[package]]
-name = "objc2-cloud-kit"
-version = "0.3.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "73ad74d880bb43877038da939b7427bba67e9dd42004a18b809ba7d87cee241c"
-dependencies = [
- "bitflags",
- "objc2",
- "objc2-foundation",
-]
-
-[[package]]
-name = "objc2-core-data"
-version = "0.3.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0b402a653efbb5e82ce4df10683b6b28027616a2715e90009947d50b8dd298fa"
-dependencies = [
- "objc2",
- "objc2-foundation",
-]
-
-[[package]]
-name = "objc2-core-foundation"
-version = "0.3.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "2a180dd8642fa45cdb7dd721cd4c11b1cadd4929ce112ebd8b9f5803cc79d536"
-dependencies = [
- "bitflags",
- "dispatch2",
- "objc2",
-]
-
-[[package]]
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-version = "0.3.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e022c9d066895efa1345f8e33e584b9f958da2fd4cd116792e15e07e4720a807"
-dependencies = [
- "bitflags",
- "dispatch2",
- "objc2",
- "objc2-core-foundation",
- "objc2-io-surface",
-]
-
-[[package]]
-name = "objc2-core-image"
-version = "0.3.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e5d563b38d2b97209f8e861173de434bd0214cf020e3423a52624cd1d989f006"
-dependencies = [
- "objc2",
- "objc2-foundation",
-]
-
-[[package]]
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-version = "0.3.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
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-dependencies = [
- "objc2",
- "objc2-foundation",
-]
-
-[[package]]
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-source = "registry+https://github.com/rust-lang/crates.io-index"
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-dependencies = [
- "bitflags",
- "objc2",
- "objc2-core-foundation",
- "objc2-core-graphics",
-]
-
-[[package]]
-name = "objc2-encode"
-version = "4.1.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ef25abbcd74fb2609453eb695bd2f860d389e457f67dc17cafc8b8cbc89d0c33"
-
-[[package]]
-name = "objc2-foundation"
-version = "0.3.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e3e0adef53c21f888deb4fa59fc59f7eb17404926ee8a6f59f5df0fd7f9f3272"
-dependencies = [
- "bitflags",
- "block2",
- "libc",
- "objc2",
- "objc2-core-foundation",
-]
-
-[[package]]
-name = "objc2-io-surface"
-version = "0.3.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "180788110936d59bab6bd83b6060ffdfffb3b922ba1396b312ae795e1de9d81d"
-dependencies = [
- "bitflags",
- "objc2",
- "objc2-core-foundation",
-]
-
-[[package]]
-name = "objc2-quartz-core"
-version = "0.3.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "96c1358452b371bf9f104e21ec536d37a650eb10f7ee379fff67d2e08d537f1f"
-dependencies = [
- "bitflags",
- "objc2",
- "objc2-core-foundation",
- "objc2-foundation",
-]
-
-[[package]]
-name = "objc2-ui-kit"
-version = "0.3.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d87d638e33c06f577498cbcc50491496a3ed4246998a7fbba7ccb98b1e7eab22"
-dependencies = [
- "bitflags",
- "block2",
- "objc2",
- "objc2-cloud-kit",
- "objc2-core-data",
- "objc2-core-foundation",
- "objc2-core-graphics",
- "objc2-core-image",
- "objc2-core-location",
- "objc2-core-text",
- "objc2-foundation",
- "objc2-quartz-core",
- "objc2-user-notifications",
-]
-
-[[package]]
-name = "objc2-user-notifications"
-version = "0.3.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9df9128cbbfef73cda168416ccf7f837b62737d748333bfe9ab71c245d76613e"
-dependencies = [
- "objc2",
- "objc2-foundation",
-]
-
 [[package]]
 name = "object"
 version = "0.37.3"
@@ -3549,18 +3372,14 @@ dependencies = [

 [[package]]
 name = "os_info"
-version = "3.14.0"
+version = "3.12.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e4022a17595a00d6a369236fdae483f0de7f0a339960a53118b818238e132224"
+checksum = "d0e1ac5fde8d43c34139135df8ea9ee9465394b2d8d20f032d38998f64afffc3"
 dependencies = [
- "android_system_properties",
 "log",
- "nix",
- "objc2",
- "objc2-foundation",
- "objc2-ui-kit",
+ "plist",
 "serde",
- "windows-sys 0.61.2",
+ "windows-sys 0.52.0",
 ]

 [[package]]
@@ -3742,6 +3561,19 @@ version = "0.3.32"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7edddbd0b52d732b21ad9a5fab5c704c14cd949e5e9a1ec5929a24fded1b904c"

+[[package]]
+name = "plist"
+version = "1.8.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "740ebea15c5d1428f910cd1a5f52cebf8d25006245ed8ade92702f4943d91e07"
+dependencies = [
+ "base64 0.22.1",
+ "indexmap",
+ "quick-xml",
+ "serde",
+ "time",
+]
+
 [[package]]
 name = "png"
 version = "0.18.1"
@@ -3925,6 +3757,15 @@ version = "2.0.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "a993555f31e5a609f617c12db6250dedcac1b0a85076912c436e6fc9b2c8e6a3"

+[[package]]
+name = "quick-xml"
+version = "0.38.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b66c2058c55a409d601666cffe35f04333cf1013010882cec174a7467cd4e21c"
+dependencies = [
+ "memchr",
+]
+
 [[package]]
 name = "quinn"
 version = "0.11.9"
@@ -4254,7 +4095,7 @@ dependencies = [
 [[package]]
 name = "ruma"
 version = "0.10.1"
-source = "git+https://forgejo.ellis.link/continuwuation/ruwuma?rev=df6fa9a394b259c9cd3420e2b52a47847510ed86#df6fa9a394b259c9cd3420e2b52a47847510ed86"
+source = "git+https://forgejo.ellis.link/continuwuation/ruwuma?rev=e087ff15888156942ca2ffe6097d1b4c3fd27628#e087ff15888156942ca2ffe6097d1b4c3fd27628"
 dependencies = [
 "assign",
 "continuwuity-admin-api",
@@ -4277,7 +4118,7 @@ dependencies = [
 [[package]]
 name = "ruma-appservice-api"
 version = "0.10.0"
-source = "git+https://forgejo.ellis.link/continuwuation/ruwuma?rev=df6fa9a394b259c9cd3420e2b52a47847510ed86#df6fa9a394b259c9cd3420e2b52a47847510ed86"
+source = "git+https://forgejo.ellis.link/continuwuation/ruwuma?rev=e087ff15888156942ca2ffe6097d1b4c3fd27628#e087ff15888156942ca2ffe6097d1b4c3fd27628"
 dependencies = [
 "js_int",
 "ruma-common",
@@ -4289,7 +4130,7 @@ dependencies = [
 [[package]]
 name = "ruma-client-api"
 version = "0.18.0"
-source = "git+https://forgejo.ellis.link/continuwuation/ruwuma?rev=df6fa9a394b259c9cd3420e2b52a47847510ed86#df6fa9a394b259c9cd3420e2b52a47847510ed86"
+source = "git+https://forgejo.ellis.link/continuwuation/ruwuma?rev=e087ff15888156942ca2ffe6097d1b4c3fd27628#e087ff15888156942ca2ffe6097d1b4c3fd27628"
 dependencies = [
 "as_variant",
 "assign",
@@ -4312,7 +4153,7 @@ dependencies = [
 [[package]]
 name = "ruma-common"
 version = "0.13.0"
-source = "git+https://forgejo.ellis.link/continuwuation/ruwuma?rev=df6fa9a394b259c9cd3420e2b52a47847510ed86#df6fa9a394b259c9cd3420e2b52a47847510ed86"
+source = "git+https://forgejo.ellis.link/continuwuation/ruwuma?rev=e087ff15888156942ca2ffe6097d1b4c3fd27628#e087ff15888156942ca2ffe6097d1b4c3fd27628"
 dependencies = [
 "as_variant",
 "base64 0.22.1",
@@ -4344,7 +4185,7 @@ dependencies = [
 [[package]]
 name = "ruma-events"
 version = "0.28.1"
-source = "git+https://forgejo.ellis.link/continuwuation/ruwuma?rev=df6fa9a394b259c9cd3420e2b52a47847510ed86#df6fa9a394b259c9cd3420e2b52a47847510ed86"
+source = "git+https://forgejo.ellis.link/continuwuation/ruwuma?rev=e087ff15888156942ca2ffe6097d1b4c3fd27628#e087ff15888156942ca2ffe6097d1b4c3fd27628"
 dependencies = [
 "as_variant",
 "indexmap",
@@ -4369,7 +4210,7 @@ dependencies = [
 [[package]]
 name = "ruma-federation-api"
 version = "0.9.0"
-source = "git+https://forgejo.ellis.link/continuwuation/ruwuma?rev=df6fa9a394b259c9cd3420e2b52a47847510ed86#df6fa9a394b259c9cd3420e2b52a47847510ed86"
+source = "git+https://forgejo.ellis.link/continuwuation/ruwuma?rev=e087ff15888156942ca2ffe6097d1b4c3fd27628#e087ff15888156942ca2ffe6097d1b4c3fd27628"
 dependencies = [
 "bytes",
 "headers",
@@ -4391,7 +4232,7 @@ dependencies = [
 [[package]]
 name = "ruma-identifiers-validation"
 version = "0.9.5"
-source = "git+https://forgejo.ellis.link/continuwuation/ruwuma?rev=df6fa9a394b259c9cd3420e2b52a47847510ed86#df6fa9a394b259c9cd3420e2b52a47847510ed86"
+source = "git+https://forgejo.ellis.link/continuwuation/ruwuma?rev=e087ff15888156942ca2ffe6097d1b4c3fd27628#e087ff15888156942ca2ffe6097d1b4c3fd27628"
 dependencies = [
 "js_int",
 "thiserror 2.0.18",
@@ -4400,7 +4241,7 @@ dependencies = [
 [[package]]
 name = "ruma-identity-service-api"
 version = "0.9.0"
-source = "git+https://forgejo.ellis.link/continuwuation/ruwuma?rev=df6fa9a394b259c9cd3420e2b52a47847510ed86#df6fa9a394b259c9cd3420e2b52a47847510ed86"
+source = "git+https://forgejo.ellis.link/continuwuation/ruwuma?rev=e087ff15888156942ca2ffe6097d1b4c3fd27628#e087ff15888156942ca2ffe6097d1b4c3fd27628"
 dependencies = [
 "js_int",
 "ruma-common",
@@ -4410,7 +4251,7 @@ dependencies = [
 [[package]]
 name = "ruma-macros"
 version = "0.13.0"
-source = "git+https://forgejo.ellis.link/continuwuation/ruwuma?rev=df6fa9a394b259c9cd3420e2b52a47847510ed86#df6fa9a394b259c9cd3420e2b52a47847510ed86"
+source = "git+https://forgejo.ellis.link/continuwuation/ruwuma?rev=e087ff15888156942ca2ffe6097d1b4c3fd27628#e087ff15888156942ca2ffe6097d1b4c3fd27628"
 dependencies = [
 "cfg-if",
 "proc-macro-crate",
@@ -4425,7 +4266,7 @@ dependencies = [
 [[package]]
 name = "ruma-push-gateway-api"
 version = "0.9.0"
-source = "git+https://forgejo.ellis.link/continuwuation/ruwuma?rev=df6fa9a394b259c9cd3420e2b52a47847510ed86#df6fa9a394b259c9cd3420e2b52a47847510ed86"
+source = "git+https://forgejo.ellis.link/continuwuation/ruwuma?rev=e087ff15888156942ca2ffe6097d1b4c3fd27628#e087ff15888156942ca2ffe6097d1b4c3fd27628"
 dependencies = [
 "js_int",
 "ruma-common",
@@ -4437,7 +4278,7 @@ dependencies = [
 [[package]]
 name = "ruma-signatures"
 version = "0.15.0"
-source = "git+https://forgejo.ellis.link/continuwuation/ruwuma?rev=df6fa9a394b259c9cd3420e2b52a47847510ed86#df6fa9a394b259c9cd3420e2b52a47847510ed86"
+source = "git+https://forgejo.ellis.link/continuwuation/ruwuma?rev=e087ff15888156942ca2ffe6097d1b4c3fd27628#e087ff15888156942ca2ffe6097d1b4c3fd27628"
 dependencies = [
 "base64 0.22.1",
 "ed25519-dalek",
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -253,7 +253,7 @@ features = [
 version = "0.4.0"

 [workspace.dependencies.libloading]
-version = "0.8.6"
+version = "0.9.0"

 # Validating urls in config, was already a transitive dependency
 [workspace.dependencies.url]
@@ -472,7 +472,7 @@ features = ["use_std"]
 version = "0.5"

 [workspace.dependencies.nix]
-version = "0.30.1"
+version = "0.31.0"
 default-features = false
 features = ["resource"]

--- a/README.md
+++ b/README.md
@@ -57,10 +57,15 @@ ### What are the project's goals?

 ### Can I try it out?

-Check out the [documentation](https://continuwuity.org) for installation instructions, or join one of these vetted public homeservers running Continuwuity to get a feel for things!
+Check out the [documentation](https://continuwuity.org) for installation instructions.

- https://continuwuity.rocks -- A public demo server operated by the Continuwuity Team.
- https://federated.nexus -- Federated Nexus is a community resource hosting multiple FOSS (especially federated) services, including Matrix and Forgejo.
+If you want to try it out as a user, we have some partnered homeservers you can use:
+* You can head over to [https://federated.nexus](https://federated.nexus/) in your browser.
+  * Hit the `Apply to Join` button. Once your request has been accepted, you will receive an email with your username and password.
+  * Head over to [https://app.federated.nexus](https://app.federated.nexus/) and you can sign in there, or use any other matrix chat client you wish elsewhere.
+  * Your username for matrix will be in the form of `@username:federated.nexus`, however you can simply use the `username` part to log in. Your password is your password.
+
+* There's also [https://continuwuity.rocks/](https://continuwuity.rocks/). You can register a new account using Cinny via [this convenient link](https://app.cinny.in/register/continuwuity.rocks), or you can use Element or another matrix client *that supports registration*.

 ### What are we working on?

--- a/changelog.d/1428.feature
+++ b/changelog.d/1428.feature
@@ -0,0 +1 @@
+Improved the concurrency handling of federation transactions, vastly improving performance and reliability by more accurately handling inbound transactions and reducing the amount of repeated wasted work. Contributed by @nex and @Jade.
--- a/changelog.d/1435.feature.md
+++ b/changelog.d/1435.feature.md
@@ -0,0 +1 @@
+Added MSC3202 Device masquerading (not all of MSC3202). This should fix issues with enabling MSC4190 for some Mautrix bridges. Contributed by @Jade
--- a/changelog.d/1441.bugfix
+++ b/changelog.d/1441.bugfix
@@ -0,0 +1 @@
+Removed the `allow_public_room_directory_without_auth` config option. Contributed by @0xnim.
--- a/changelog.d/url-preview-fix.feature
+++ b/changelog.d/url-preview-fix.feature
@@ -0,0 +1 @@
+Improved URL preview fetching with a more compatible user agent for sites like YouTube Music. Added `!admin media delete-url-preview <url>` command to clear cached URL previews that were stuck and broken.
--- a/complement/complement.config.toml
+++ b/complement/complement.config.toml
@@ -9,7 +9,6 @@ address = "0.0.0.0"
 allow_device_name_federation = true
 allow_guest_registration = true
 allow_public_room_directory_over_federation = true
-allow_public_room_directory_without_auth = true
 allow_registration = true
 database_path = "/database"
 log = "trace,h2=debug,hyper=debug"
--- a/conduwuit-example.toml
+++ b/conduwuit-example.toml
@@ -290,6 +290,25 @@
 #
 #max_fetch_prev_events = 192

+# How many incoming federation transactions the server is willing to be
+# processing at any given time before it becomes overloaded and starts
+# rejecting further transactions until some slots become available.
+#
+# Setting this value too low or too high may result in unstable
+# federation, and setting it too high may cause runaway resource usage.
+#
+#max_concurrent_inbound_transactions = 150
+
+# Maximum age (in seconds) for cached federation transaction responses.
+# Entries older than this will be removed during cleanup.
+#
+#transaction_id_cache_max_age_secs = 7200 (2 hours)
+
+# Maximum number of cached federation transaction responses.
+# When the cache exceeds this limit, older entries will be removed.
+#
+#transaction_id_cache_max_entries = 8192
+
 # Default/base connection timeout (seconds). This is used only by URL
 # previews and update/news endpoint checks.
 #
@@ -527,12 +546,6 @@
 #
 #allow_public_room_directory_over_federation = false

-# Set this to true to allow your server's public room directory to be
-# queried without client authentication (access token) through the Client
-# APIs. Set this to false to protect against /publicRooms spiders.
-#
-#allow_public_room_directory_without_auth = false
-
 # Allow guests/unauthenticated users to access TURN credentials.
 #
 # This is the equivalent of Synapse's `turn_allow_guests` config option.
@@ -1325,7 +1338,7 @@
 # sender user's server name, inbound federation X-Matrix origin, and
 # outbound federation handler.
 #
-# You can set this to ["*"] to block all servers by default, and then
+# You can set this to [".*"] to block all servers by default, and then
 # use `allowed_remote_server_names` to allow only specific servers.
 #
 # example: ["badserver\\.tld$", "badphrase", "19dollarfortnitecards"]
--- a/docker/Dockerfile
+++ b/docker/Dockerfile
@@ -52,7 +52,7 @@ ENV BINSTALL_VERSION=1.17.5
 # renovate: datasource=github-releases depName=psastras/sbom-rs
 ENV CARGO_SBOM_VERSION=0.9.1
 # renovate: datasource=crate depName=lddtree
-ENV LDDTREE_VERSION=0.4.0
+ENV LDDTREE_VERSION=0.5.0
 # renovate: datasource=crate depName=timelord-cli
 ENV TIMELORD_VERSION=3.0.1

--- a/docker/musl.Dockerfile
+++ b/docker/musl.Dockerfile
@@ -22,7 +22,7 @@ ENV BINSTALL_VERSION=1.17.5
 # renovate: datasource=github-releases depName=psastras/sbom-rs
 ENV CARGO_SBOM_VERSION=0.9.1
 # renovate: datasource=crate depName=lddtree
-ENV LDDTREE_VERSION=0.4.0
+ENV LDDTREE_VERSION=0.5.0

 # Install unpackaged tools
 RUN <<EOF
--- a/docs/introduction.mdx
+++ b/docs/introduction.mdx
@@ -51,7 +51,13 @@ ## Can I try it out?

 Check out the [documentation](https://continuwuity.org) for installation instructions.

-There are currently no open registration continuwuity instances available.
+If you want to try it out as a user, we have some partnered homeservers you can use:
+* You can head over to [https://federated.nexus](https://federated.nexus/) in your browser.
+  * Hit the `Apply to Join` button. Once your request has been accepted, you will receive an email with your username and password.
+  * Head over to [https://app.federated.nexus](https://app.federated.nexus/) and you can sign in there, or use any other matrix chat client you wish elsewhere.
+  * Your username for matrix will be in the form of `@username:federated.nexus`, however you can simply use the `username` part to log in. Your password is your password.
+
+* There's also [https://continuwuity.rocks/](https://continuwuity.rocks/). You can register a new account using Cinny via [this convenient link](https://app.cinny.in/register/continuwuity.rocks), or you can use Element or another matrix client *that supports registration*.

 ## What are we working on?

--- a/docs/reference/admin/media.md
+++ b/docs/reference/admin/media.md
@@ -36,3 +36,7 @@ ## `!admin media delete-all-from-user`
 ## `!admin media delete-all-from-server`

 Deletes all remote media from the specified remote server. This will always ignore errors by default
+
+## `!admin media delete-url-preview`
+
+Deletes a cached URL preview, forcing it to be re-fetched. Use --all to purge all cached URL previews
--- a/nix/packages/uwulib/build.nix
+++ b/nix/packages/uwulib/build.nix
@@ -77,7 +77,12 @@ rec {
    craneLib.buildDepsOnly (
      (commonAttrs commonAttrsArgs)
      // {
-        env = uwuenv.buildDepsOnlyEnv // (makeRocksDBEnv { inherit rocksdb; });
+        env = uwuenv.buildDepsOnlyEnv
+              // (makeRocksDBEnv { inherit rocksdb; })
+              // {
+                # required since we started using unstable reqwest apparently ... otherwise the all-features build will fail
+                RUSTFLAGS = "--cfg reqwest_unstable";
+              };
        inherit (features) cargoExtraArgs;
      }

@@ -102,7 +107,13 @@ rec {
        '';
        cargoArtifacts = deps;
        doCheck = true;
-        env = uwuenv.buildPackageEnv // rocksdbEnv;
+        env =
+          uwuenv.buildPackageEnv
+          // rocksdbEnv
+          // {
+            # required since we started using unstable reqwest apparently ... otherwise the all-features build will fail
+            RUSTFLAGS = "--cfg reqwest_unstable";
+          };
        passthru.env = uwuenv.buildPackageEnv // rocksdbEnv;
        meta.mainProgram = crateInfo.pname;
        inherit (features) cargoExtraArgs;
--- a/src/admin/federation/commands.rs
+++ b/src/admin/federation/commands.rs
@@ -30,12 +30,15 @@ pub(super) async fn incoming_federation(&self) -> Result {
 			.federation_handletime
 			.read();

-		let mut msg = format!("Handling {} incoming pdus:\n", map.len());
+		let mut msg = format!(
+			"Handling {} incoming PDUs across {} active transactions:\n",
+			map.len(),
+			self.services.transactions.txn_active_handle_count()
+		);
 		for (r, (e, i)) in map.iter() {
 			let elapsed = i.elapsed();
 			writeln!(msg, "{} {}: {}m{}s", r, e, elapsed.as_secs() / 60, elapsed.as_secs() % 60)?;
 		}
-
 		msg
 	};

--- a/src/admin/media/commands.rs
+++ b/src/admin/media/commands.rs
@@ -388,3 +388,19 @@ pub(super) async fn get_remote_thumbnail(
 	self.write_str(&format!("```\n{result:#?}\nreceived {len} bytes for file content.\n```"))
 		.await
 }
+
+#[admin_command]
+pub(super) async fn delete_url_preview(&self, url: Option<String>, all: bool) -> Result {
+	if all {
+		self.services.media.clear_url_previews().await;
+
+		return self.write_str("Deleted all cached URL previews.").await;
+	}
+
+	let url = url.expect("clap enforces url is required unless --all");
+
+	self.services.media.remove_url_preview(&url).await?;
+
+	self.write_str(&format!("Deleted cached URL preview for: {url}"))
+		.await
+}
--- a/src/admin/media/mod.rs
+++ b/src/admin/media/mod.rs
@@ -108,4 +108,16 @@ pub enum MediaCommand {
 		#[arg(long, default_value("800"))]
 		height: u32,
 	},
+
+	/// Deletes a cached URL preview, forcing it to be re-fetched.
+	/// Use --all to purge all cached URL previews.
+	DeleteUrlPreview {
+		/// The URL to clear from the saved preview data
+		#[arg(required_unless_present = "all")]
+		url: Option<String>,
+
+		/// Purge all cached URL previews
+		#[arg(long, conflicts_with = "url")]
+		all: bool,
+	},
 }
--- a/src/admin/query/raw.rs
+++ b/src/admin/query/raw.rs
@@ -209,7 +209,7 @@ pub(super) async fn compact(
 	let parallelism = parallelism.unwrap_or(1);
 	let results = maps
 		.into_iter()
-		.try_stream()
+		.try_stream::<conduwuit::Error>()
 		.paralleln_and_then(runtime, parallelism, move |map| {
 			map.compact_blocking(options.clone())?;
 			Ok(map.name().to_owned())
--- a/src/admin/query/resolver.rs
+++ b/src/admin/query/resolver.rs
@@ -20,7 +20,17 @@ pub enum ResolverCommand {
 		name: Option<String>,
 	},

-	/// Flush a specific server from the resolver caches or everything
+	/// Flush a given server from the resolver caches or flush them completely
+	///
+	/// * Examples:
+	///   * Flush a specific server:
+	///
+	///     `!admin query resolver flush-cache matrix.example.com`
+	///
+	///   * Flush all resolver caches completely:
+	///
+	///     `!admin query resolver flush-cache --all`
+	#[command(verbatim_doc_comment)]
 	FlushCache {
 		name: Option<OwnedServerName>,

--- a/src/api/client/account.rs
+++ b/src/api/client/account.rs
@@ -252,6 +252,13 @@ pub(crate) async fn register_route(
 						}
 					}

+					// Don't allow registration with user IDs that aren't local
+					if !services.globals.user_is_local(&user_id) {
+						return Err!(Request(InvalidUsername(
+							"Username {body_username} is not local to this server"
+						)));
+					}
+
 					user_id
 				},
 				| Err(e) => {
--- a/src/api/client/media.rs
+++ b/src/api/client/media.rs
@@ -6,6 +6,7 @@
 	Err, Result, err,
 	utils::{self, content_disposition::make_content_disposition, math::ruma_from_usize},
 };
+use conduwuit_core::error;
 use conduwuit_service::{
 	Services,
 	media::{CACHE_CONTROL_IMMUTABLE, CORP_CROSS_ORIGIN, Dim, FileMeta, MXC_LENGTH},
@@ -144,12 +145,22 @@ pub(crate) async fn get_content_route(
 		server_name: &body.server_name,
 		media_id: &body.media_id,
 	};
-
 	let FileMeta {
 		content,
 		content_type,
 		content_disposition,
-	} = fetch_file(&services, &mxc, user, body.timeout_ms, None).await?;
+	} = match fetch_file(&services, &mxc, user, body.timeout_ms, None).await {
+		| Ok(meta) => meta,
+		| Err(conduwuit::Error::Io(e)) => match e.kind() {
+			| std::io::ErrorKind::NotFound => return Err!(Request(NotFound("Media not found."))),
+			| std::io::ErrorKind::PermissionDenied => {
+				error!("Permission denied when trying to read file: {e:?}");
+				return Err!(Request(Unknown("Unknown error when fetching file.")));
+			},
+			| _ => return Err!(Request(Unknown("Unknown error when fetching file."))),
+		},
+		| Err(_) => return Err!(Request(Unknown("Unknown error when fetching file."))),
+	};

 	Ok(get_content::v1::Response {
 		file: content.expect("entire file contents"),
@@ -185,7 +196,18 @@ pub(crate) async fn get_content_as_filename_route(
 		content,
 		content_type,
 		content_disposition,
-	} = fetch_file(&services, &mxc, user, body.timeout_ms, Some(&body.filename)).await?;
+	} = match fetch_file(&services, &mxc, user, body.timeout_ms, None).await {
+		| Ok(meta) => meta,
+		| Err(conduwuit::Error::Io(e)) => match e.kind() {
+			| std::io::ErrorKind::NotFound => return Err!(Request(NotFound("Media not found."))),
+			| std::io::ErrorKind::PermissionDenied => {
+				error!("Permission denied when trying to read file: {e:?}");
+				return Err!(Request(Unknown("Unknown error when fetching file.")));
+			},
+			| _ => return Err!(Request(Unknown("Unknown error when fetching file."))),
+		},
+		| Err(_) => return Err!(Request(Unknown("Unknown error when fetching file."))),
+	};

 	Ok(get_content_as_filename::v1::Response {
 		file: content.expect("entire file contents"),
--- a/src/api/client/report.rs
+++ b/src/api/client/report.rs
@@ -4,7 +4,6 @@
 use axum_client_ip::InsecureClientIp;
 use conduwuit::{Err, Event, Result, debug_info, info, matrix::pdu::PduEvent, utils::ReadyExt};
 use conduwuit_service::Services;
-use rand::Rng;
 use ruma::{
 	EventId, OwnedEventId, OwnedRoomId, OwnedUserId, RoomId, UserId,
 	api::client::{
--- a/src/api/client/send.rs
+++ b/src/api/client/send.rs
@@ -50,8 +50,8 @@ pub(crate) async fn send_message_event_route(

 	// Check if this is a new transaction id
 	if let Ok(response) = services
-		.transaction_ids
-		.existing_txnid(sender_user, sender_device, &body.txn_id)
+		.transactions
+		.get_client_txn(sender_user, sender_device, &body.txn_id)
 		.await
 	{
 		// The client might have sent a txnid of the /sendToDevice endpoint
@@ -92,7 +92,7 @@ pub(crate) async fn send_message_event_route(
 		)
 		.await?;

-	services.transaction_ids.add_txnid(
+	services.transactions.add_client_txnid(
 		sender_user,
 		sender_device,
 		&body.txn_id,
--- a/src/api/client/sync/v3/joined.rs
+++ b/src/api/client/sync/v3/joined.rs
@@ -65,6 +65,8 @@ pub(super) async fn load_joined_room(
 	and `join*` functions are used to perform steps in parallel which do not depend on each other.
 	*/

+	let insert_lock = services.rooms.timeline.mutex_insert.lock(room_id).await;
+	drop(insert_lock);
 	let (
 		account_data,
 		ephemeral,
@@ -270,7 +272,7 @@ async fn build_state_and_timeline(
 	// joined since the last sync, that being the syncing user's join event. if
 	// it's empty something is wrong.
 	if joined_since_last_sync && timeline.pdus.is_empty() {
-		warn!("timeline for newly joined room is empty");
+		debug_warn!("timeline for newly joined room is empty");
 	}

 	let (summary, device_list_updates) = try_join(
--- a/src/api/client/to_device.rs
+++ b/src/api/client/to_device.rs
@@ -26,8 +26,8 @@ pub(crate) async fn send_event_to_device_route(

 	// Check if this is a new transaction id
 	if services
-		.transaction_ids
-		.existing_txnid(sender_user, sender_device, &body.txn_id)
+		.transactions
+		.get_client_txn(sender_user, sender_device, &body.txn_id)
 		.await
 		.is_ok()
 	{
@@ -104,8 +104,8 @@ pub(crate) async fn send_event_to_device_route(

 	// Save transaction id with empty data
 	services
-		.transaction_ids
-		.add_txnid(sender_user, sender_device, &body.txn_id, &[]);
+		.transactions
+		.add_client_txnid(sender_user, sender_device, &body.txn_id, &[]);

 	Ok(send_event_to_device::v3::Response {})
 }
--- a/src/api/router/auth.rs
+++ b/src/api/router/auth.rs
@@ -14,7 +14,8 @@
 	pin_mut,
 };
 use ruma::{
-	CanonicalJsonObject, CanonicalJsonValue, OwnedDeviceId, OwnedServerName, OwnedUserId, UserId,
+	CanonicalJsonObject, CanonicalJsonValue, DeviceId, OwnedDeviceId, OwnedServerName,
+	OwnedUserId, UserId,
 	api::{
 		AuthScheme, IncomingRequest, Metadata,
 		client::{
@@ -66,23 +67,17 @@ pub(super) async fn auth(
 	if metadata.authentication == AuthScheme::None {
 		match metadata {
 			| &get_public_rooms::v3::Request::METADATA => {
-				if !services
-					.server
-					.config
-					.allow_public_room_directory_without_auth
-				{
-					match token {
-						| Token::Appservice(_) | Token::User(_) => {
-							// we should have validated the token above
-							// already
-						},
-						| Token::None | Token::Invalid => {
-							return Err(Error::BadRequest(
-								ErrorKind::MissingToken,
-								"Missing or invalid access token.",
-							));
-						},
-					}
+				match token {
+					| Token::Appservice(_) | Token::User(_) => {
+						// we should have validated the token above
+						// already
+					},
+					| Token::None | Token::Invalid => {
+						return Err(Error::BadRequest(
+							ErrorKind::MissingToken,
+							"Missing or invalid access token.",
+						));
+					},
 				}
 			},
 			| &get_profile::v3::Request::METADATA
@@ -234,10 +229,33 @@ async fn auth_appservice(
 		return Err!(Request(Exclusive("User is not in namespace.")));
 	}

+	// MSC3202/MSC4190: Handle device_id masquerading for appservices.
+	// The device_id can be provided via `device_id` or
+	// `org.matrix.msc3202.device_id` query parameter.
+	let sender_device = if let Some(ref device_id_str) = request.query.device_id {
+		let device_id: &DeviceId = device_id_str.as_str().into();
+
+		// Verify the device exists for this user
+		if services
+			.users
+			.get_device_metadata(&user_id, device_id)
+			.await
+			.is_err()
+		{
+			return Err!(Request(Forbidden(
+				"Device does not exist for user or appservice cannot masquerade as this device."
+			)));
+		}
+
+		Some(device_id.to_owned())
+	} else {
+		None
+	};
+
 	Ok(Auth {
 		origin: None,
 		sender_user: Some(user_id),
-		sender_device: None,
+		sender_device,
 		appservice_info: Some(*info),
 	})
 }
--- a/src/api/router/request.rs
+++ b/src/api/router/request.rs
@@ -11,6 +11,10 @@
 pub(super) struct QueryParams {
 	pub(super) access_token: Option<String>,
 	pub(super) user_id: Option<String>,
+	/// Device ID for appservice device masquerading (MSC3202/MSC4190).
+	/// Can be provided as `device_id` or `org.matrix.msc3202.device_id`.
+	#[serde(alias = "org.matrix.msc3202.device_id")]
+	pub(super) device_id: Option<String>,
 }

 pub(super) struct Request {
--- a/src/api/server/send.rs
+++ b/src/api/server/send.rs
@@ -1,27 +1,33 @@
-use std::{collections::BTreeMap, net::IpAddr, time::Instant};
+use std::{
+	collections::{BTreeMap, HashMap, HashSet},
+	net::IpAddr,
+	time::{Duration, Instant},
+};

 use axum::extract::State;
 use axum_client_ip::InsecureClientIp;
 use conduwuit::{
 	Err, Error, Result, debug, debug_warn, err, error,
 	result::LogErr,
+	state_res::lexicographical_topological_sort,
 	trace,
 	utils::{
 		IterStream, ReadyExt, millis_since_unix_epoch,
 		stream::{BroadbandExt, TryBroadbandExt, automatic_width},
 	},
-	warn,
 };
 use conduwuit_service::{
 	Services,
 	sending::{EDU_LIMIT, PDU_LIMIT},
 };
 use futures::{FutureExt, Stream, StreamExt, TryFutureExt, TryStreamExt};
+use http::StatusCode;
 use itertools::Itertools;
 use ruma::{
-	CanonicalJsonObject, OwnedEventId, OwnedRoomId, OwnedUserId, RoomId, ServerName, UserId,
+	CanonicalJsonObject, MilliSecondsSinceUnixEpoch, OwnedEventId, OwnedRoomId, OwnedUserId,
+	RoomId, ServerName, UserId,
 	api::{
-		client::error::ErrorKind,
+		client::error::{ErrorKind, ErrorKind::LimitExceeded},
 		federation::transactions::{
 			edu::{
 				DeviceListUpdateContent, DirectDeviceContent, Edu, PresenceContent,
@@ -32,9 +38,16 @@
 		},
 	},
 	events::receipt::{ReceiptEvent, ReceiptEventContent, ReceiptType},
+	int,
 	serde::Raw,
 	to_device::DeviceIdOrAllDevices,
+	uint,
 };
+use service::transactions::{
+	FederationTxnState, TransactionError, TxnKey, WrappedTransactionResponse,
+};
+use tokio::sync::watch::{Receiver, Sender};
+use tracing::instrument;

 use crate::Ruma;

@@ -44,15 +57,6 @@
 /// # `PUT /_matrix/federation/v1/send/{txnId}`
 ///
 /// Push EDUs and PDUs to this server.
-#[tracing::instrument(
-	name = "txn",
-	level = "debug",
-	skip_all,
-	fields(
-		%client,
-		origin = body.origin().as_str()
-	),
-)]
 pub(crate) async fn send_transaction_message_route(
 	State(services): State<crate::State>,
 	InsecureClientIp(client): InsecureClientIp,
@@ -76,16 +80,73 @@ pub(crate) async fn send_transaction_message_route(
 		)));
 	}

-	let txn_start_time = Instant::now();
-	trace!(
-		pdus = body.pdus.len(),
-		edus = body.edus.len(),
-		elapsed = ?txn_start_time.elapsed(),
-		id = %body.transaction_id,
-		origin = %body.origin(),
-		"Starting txn",
-	);
+	let txn_key = (body.origin().to_owned(), body.transaction_id.clone());

+	// Atomically check cache, join active, or start new transaction
+	match services
+		.transactions
+		.get_or_start_federation_txn(txn_key.clone())?
+	{
+		| FederationTxnState::Cached(response) => {
+			// Already responded
+			Ok(response)
+		},
+		| FederationTxnState::Active(receiver) => {
+			// Another thread is processing
+			wait_for_result(receiver).await
+		},
+		| FederationTxnState::Started { receiver, sender } => {
+			// We're the first, spawn the processing task
+			services
+				.server
+				.runtime()
+				.spawn(process_inbound_transaction(services, body, client, txn_key, sender));
+			// and wait for it
+			wait_for_result(receiver).await
+		},
+	}
+}
+
+async fn wait_for_result(
+	mut recv: Receiver<WrappedTransactionResponse>,
+) -> Result<send_transaction_message::v1::Response> {
+	if tokio::time::timeout(Duration::from_secs(50), recv.changed())
+		.await
+		.is_err()
+	{
+		// Took too long, return 429 to encourage the sender to try again
+		return Err(Error::BadRequest(
+			LimitExceeded { retry_after: None },
+			"Transaction is being still being processed. Please try again later.",
+		));
+	}
+	let value = recv.borrow_and_update();
+	match value.clone() {
+		| Some(Ok(response)) => Ok(response),
+		| Some(Err(err)) => Err(transaction_error_to_response(&err)),
+		| None => Err(Error::Request(
+			ErrorKind::Unknown,
+			"Transaction processing failed unexpectedly".into(),
+			StatusCode::INTERNAL_SERVER_ERROR,
+		)),
+	}
+}
+
+#[instrument(
+	skip_all,
+	fields(
+		id = ?body.transaction_id.as_str(),
+		origin = ?body.origin()
+	)
+)]
+async fn process_inbound_transaction(
+	services: crate::State,
+	body: Ruma<send_transaction_message::v1::Request>,
+	client: IpAddr,
+	txn_key: TxnKey,
+	sender: Sender<WrappedTransactionResponse>,
+) {
+	let txn_start_time = Instant::now();
 	let pdus = body
 		.pdus
 		.iter()
@@ -102,40 +163,79 @@ pub(crate) async fn send_transaction_message_route(
 		.filter_map(Result::ok)
 		.stream();

-	let results = handle(&services, &client, body.origin(), txn_start_time, pdus, edus).await?;
+	debug!(pdus = body.pdus.len(), edus = body.edus.len(), "Processing transaction",);
+	let results = match handle(&services, &client, body.origin(), pdus, edus).await {
+		| Ok(results) => results,
+		| Err(err) => {
+			fail_federation_txn(services, &txn_key, &sender, err);
+			return;
+		},
+	};
+
+	for (id, result) in &results {
+		if let Err(e) = result {
+			if matches!(e, Error::BadRequest(ErrorKind::NotFound, _)) {
+				debug_warn!("Incoming PDU failed {id}: {e:?}");
+			}
+		}
+	}

 	debug!(
 		pdus = body.pdus.len(),
 		edus = body.edus.len(),
 		elapsed = ?txn_start_time.elapsed(),
-		id = %body.transaction_id,
-		origin = %body.origin(),
-		"Finished txn",
+		"Finished processing transaction"
 	);
-	for (id, result) in &results {
-		if let Err(e) = result {
-			if matches!(e, Error::BadRequest(ErrorKind::NotFound, _)) {
-				warn!("Incoming PDU failed {id}: {e:?}");
-			}
-		}
-	}

-	Ok(send_transaction_message::v1::Response {
+	let response = send_transaction_message::v1::Response {
 		pdus: results
 			.into_iter()
 			.map(|(e, r)| (e, r.map_err(error::sanitized_message)))
 			.collect(),
-	})
+	};
+
+	services
+		.transactions
+		.finish_federation_txn(txn_key, sender, response);
 }

+/// Handles a failed federation transaction by sending the error through
+/// the channel and cleaning up the transaction state. This allows waiters to
+/// receive an appropriate error response.
+fn fail_federation_txn(
+	services: crate::State,
+	txn_key: &TxnKey,
+	sender: &Sender<WrappedTransactionResponse>,
+	err: TransactionError,
+) {
+	debug!("Transaction failed: {err}");
+
+	// Remove from active state so the transaction can be retried
+	services.transactions.remove_federation_txn(txn_key);
+
+	// Send the error to any waiters
+	if let Err(e) = sender.send(Some(Err(err))) {
+		debug_warn!("Failed to send transaction error to receivers: {e}");
+	}
+}
+
+/// Converts a TransactionError into an appropriate HTTP error response.
+fn transaction_error_to_response(err: &TransactionError) -> Error {
+	match err {
+		| TransactionError::ShuttingDown => Error::Request(
+			ErrorKind::Unknown,
+			"Server is shutting down, please retry later".into(),
+			StatusCode::SERVICE_UNAVAILABLE,
+		),
+	}
+}
 async fn handle(
 	services: &Services,
 	client: &IpAddr,
 	origin: &ServerName,
-	started: Instant,
 	pdus: impl Stream<Item = Pdu> + Send,
 	edus: impl Stream<Item = Edu> + Send,
-) -> Result<ResolvedMap> {
+) -> std::result::Result<ResolvedMap, TransactionError> {
 	// group pdus by room
 	let pdus = pdus
 		.collect()
@@ -152,7 +252,7 @@ async fn handle(
 		.into_iter()
 		.try_stream()
 		.broad_and_then(|(room_id, pdus): (_, Vec<_>)| {
-			handle_room(services, client, origin, started, room_id, pdus.into_iter())
+			handle_room(services, client, origin, room_id, pdus.into_iter())
 				.map_ok(Vec::into_iter)
 				.map_ok(IterStream::try_stream)
 		})
@@ -169,14 +269,51 @@ async fn handle(
 	Ok(results)
 }

+/// Attempts to build a localised directed acyclic graph out of the given PDUs,
+/// returning them in a topologically sorted order.
+///
+/// This is used to attempt to process PDUs in an order that respects their
+/// dependencies, however it is ultimately the sender's responsibility to send
+/// them in a processable order, so this is just a best effort attempt. It does
+/// not account for power levels or other tie breaks.
+async fn build_local_dag(
+	pdu_map: &HashMap<OwnedEventId, CanonicalJsonObject>,
+) -> Result<Vec<OwnedEventId>> {
+	debug_assert!(pdu_map.len() >= 2, "needless call to build_local_dag with less than 2 PDUs");
+	let mut dag: HashMap<OwnedEventId, HashSet<OwnedEventId>> = HashMap::new();
+
+	for (event_id, value) in pdu_map {
+		let prev_events = value
+			.get("prev_events")
+			.expect("pdu must have prev_events")
+			.as_array()
+			.expect("prev_events must be an array")
+			.iter()
+			.map(|v| {
+				OwnedEventId::parse(v.as_str().expect("prev_events values must be strings"))
+					.expect("prev_events must be valid event IDs")
+			})
+			.collect::<HashSet<OwnedEventId>>();
+
+		dag.insert(event_id.clone(), prev_events);
+	}
+	lexicographical_topological_sort(&dag, &|_| async {
+		// Note: we don't bother fetching power levels because that would massively slow
+		// this function down. This is a best-effort attempt to order events correctly
+		// for processing, however ultimately that should be the sender's job.
+		Ok((int!(0), MilliSecondsSinceUnixEpoch(uint!(0))))
+	})
+	.await
+	.map_err(|e| err!("failed to resolve local graph: {e}"))
+}
+
 async fn handle_room(
 	services: &Services,
 	_client: &IpAddr,
 	origin: &ServerName,
-	txn_start_time: Instant,
 	room_id: OwnedRoomId,
 	pdus: impl Iterator<Item = Pdu> + Send,
-) -> Result<Vec<(OwnedEventId, Result)>> {
+) -> std::result::Result<Vec<(OwnedEventId, Result)>, TransactionError> {
 	let _room_lock = services
 		.rooms
 		.event_handler
@@ -185,27 +322,40 @@ async fn handle_room(
 		.await;

 	let room_id = &room_id;
-	pdus.try_stream()
-		.and_then(|(_, event_id, value)| async move {
-			services.server.check_running()?;
-			let pdu_start_time = Instant::now();
-			let result = services
-				.rooms
-				.event_handler
-				.handle_incoming_pdu(origin, room_id, &event_id, value, true)
-				.await
-				.map(|_| ());
-
-			debug!(
-				pdu_elapsed = ?pdu_start_time.elapsed(),
-				txn_elapsed = ?txn_start_time.elapsed(),
-				"Finished PDU {event_id}",
-			);
-
-			Ok((event_id, result))
+	let pdu_map: HashMap<OwnedEventId, CanonicalJsonObject> = pdus
+		.into_iter()
+		.map(|(_, event_id, value)| (event_id, value))
+		.collect();
+	// Try to sort PDUs by their dependencies, but fall back to arbitrary order on
+	// failure (e.g., cycles). This is best-effort; proper ordering is the sender's
+	// responsibility.
+	let sorted_event_ids = if pdu_map.len() >= 2 {
+		build_local_dag(&pdu_map).await.unwrap_or_else(|e| {
+			debug_warn!("Failed to build local DAG for room {room_id}: {e}");
+			pdu_map.keys().cloned().collect()
 		})
-		.try_collect()
-		.await
+	} else {
+		pdu_map.keys().cloned().collect()
+	};
+	let mut results = Vec::with_capacity(sorted_event_ids.len());
+	for event_id in sorted_event_ids {
+		let value = pdu_map
+			.get(&event_id)
+			.expect("sorted event IDs must be from the original map")
+			.clone();
+		services
+			.server
+			.check_running()
+			.map_err(|_| TransactionError::ShuttingDown)?;
+		let result = services
+			.rooms
+			.event_handler
+			.handle_incoming_pdu(origin, room_id, &event_id, value, true)
+			.await
+			.map(|_| ());
+		results.push((event_id, result));
+	}
+	Ok(results)
 }

 async fn handle_edu(services: &Services, client: &IpAddr, origin: &ServerName, edu: Edu) {
@@ -478,8 +628,8 @@ async fn handle_edu_direct_to_device(

 	// Check if this is a new transaction id
 	if services
-		.transaction_ids
-		.existing_txnid(sender, None, message_id)
+		.transactions
+		.get_client_txn(sender, None, message_id)
 		.await
 		.is_ok()
 	{
@@ -498,8 +648,8 @@ async fn handle_edu_direct_to_device(

 	// Save transaction id with empty data
 	services
-		.transaction_ids
-		.add_txnid(sender, None, message_id, &[]);
+		.transactions
+		.add_client_txnid(sender, None, message_id, &[]);
 }

 async fn handle_edu_direct_to_device_user<Event: Send + Sync>(
--- a/src/core/config/mod.rs
+++ b/src/core/config/mod.rs
@@ -368,6 +368,31 @@ pub struct Config {
 	#[serde(default = "default_max_fetch_prev_events")]
 	pub max_fetch_prev_events: u16,

+	/// How many incoming federation transactions the server is willing to be
+	/// processing at any given time before it becomes overloaded and starts
+	/// rejecting further transactions until some slots become available.
+	///
+	/// Setting this value too low or too high may result in unstable
+	/// federation, and setting it too high may cause runaway resource usage.
+	///
+	/// default: 150
+	#[serde(default = "default_max_concurrent_inbound_transactions")]
+	pub max_concurrent_inbound_transactions: usize,
+
+	/// Maximum age (in seconds) for cached federation transaction responses.
+	/// Entries older than this will be removed during cleanup.
+	///
+	/// default: 7200 (2 hours)
+	#[serde(default = "default_transaction_id_cache_max_age_secs")]
+	pub transaction_id_cache_max_age_secs: u64,
+
+	/// Maximum number of cached federation transaction responses.
+	/// When the cache exceeds this limit, older entries will be removed.
+	///
+	/// default: 8192
+	#[serde(default = "default_transaction_id_cache_max_entries")]
+	pub transaction_id_cache_max_entries: usize,
+
 	/// Default/base connection timeout (seconds). This is used only by URL
 	/// previews and update/news endpoint checks.
 	///
@@ -653,12 +678,6 @@ pub struct Config {
 	#[serde(default)]
 	pub allow_public_room_directory_over_federation: bool,

-	/// Set this to true to allow your server's public room directory to be
-	/// queried without client authentication (access token) through the Client
-	/// APIs. Set this to false to protect against /publicRooms spiders.
-	#[serde(default)]
-	pub allow_public_room_directory_without_auth: bool,
-
 	/// Allow guests/unauthenticated users to access TURN credentials.
 	///
 	/// This is the equivalent of Synapse's `turn_allow_guests` config option.
@@ -1525,7 +1544,7 @@ pub struct Config {
 	/// sender user's server name, inbound federation X-Matrix origin, and
 	/// outbound federation handler.
 	///
-	/// You can set this to ["*"] to block all servers by default, and then
+	/// You can set this to [".*"] to block all servers by default, and then
 	/// use `allowed_remote_server_names` to allow only specific servers.
 	///
 	/// example: ["badserver\\.tld$", "badphrase", "19dollarfortnitecards"]
@@ -2540,6 +2559,12 @@ fn default_pusher_idle_timeout() -> u64 { 15 }

 fn default_max_fetch_prev_events() -> u16 { 192_u16 }

+fn default_max_concurrent_inbound_transactions() -> usize { 150 }
+
+fn default_transaction_id_cache_max_age_secs() -> u64 { 60 * 60 * 2 }
+
+fn default_transaction_id_cache_max_entries() -> usize { 8192 }
+
 fn default_tracing_flame_filter() -> String {
 	cfg!(debug_assertions)
 		.then_some("trace,h2=off")
--- a/src/core/info/version.rs
+++ b/src/core/info/version.rs
@@ -14,6 +14,7 @@
 static VERSION: OnceLock<String> = OnceLock::new();
 static VERSION_UA: OnceLock<String> = OnceLock::new();
 static USER_AGENT: OnceLock<String> = OnceLock::new();
+static USER_AGENT_MEDIA: OnceLock<String> = OnceLock::new();

 #[inline]
 #[must_use]
@@ -21,14 +22,22 @@ pub fn name() -> &'static str { BRANDING }

 #[inline]
 pub fn version() -> &'static str { VERSION.get_or_init(init_version) }
+
 #[inline]
 pub fn version_ua() -> &'static str { VERSION_UA.get_or_init(init_version_ua) }

 #[inline]
 pub fn user_agent() -> &'static str { USER_AGENT.get_or_init(init_user_agent) }

+#[inline]
+pub fn user_agent_media() -> &'static str { USER_AGENT_MEDIA.get_or_init(init_user_agent_media) }
+
 fn init_user_agent() -> String { format!("{}/{} (bot; +{WEBSITE})", name(), version_ua()) }

+fn init_user_agent_media() -> String {
+	format!("{}/{} (embedbot; facebookexternalhit/1.1; +{WEBSITE})", name(), version_ua())
+}
+
 fn init_version_ua() -> String {
 	conduwuit_build_metadata::version_tag()
 		.map_or_else(|| SEMANTIC.to_owned(), |extra| format!("{SEMANTIC}+{extra}"))
--- a/src/core/utils/rand.rs
+++ b/src/core/utils/rand.rs
@@ -4,7 +4,7 @@
 };

 use arrayvec::ArrayString;
-use rand::{Rng, RngExt, seq::SliceRandom};
+use rand::{RngExt, seq::SliceRandom};

 pub fn shuffle<T>(vec: &mut [T]) {
 	let mut rng = rand::rng();
--- a/src/core/utils/stream/iter_stream.rs
+++ b/src/core/utils/stream/iter_stream.rs
@@ -3,19 +3,17 @@
 	stream::{Stream, TryStream},
 };

-use crate::{Error, Result};
-
 pub trait IterStream<I: IntoIterator + Send> {
 	/// Convert an Iterator into a Stream
 	fn stream(self) -> impl Stream<Item = <I as IntoIterator>::Item> + Send;

-	/// Convert an Iterator into a TryStream
-	fn try_stream(
+	/// Convert an Iterator into a TryStream with a generic error type
+	fn try_stream<E>(
 		self,
 	) -> impl TryStream<
 		Ok = <I as IntoIterator>::Item,
-		Error = Error,
-		Item = Result<<I as IntoIterator>::Item, Error>,
+		Error = E,
+		Item = Result<<I as IntoIterator>::Item, E>,
 	> + Send;
 }

@@ -28,12 +26,12 @@ impl<I> IterStream<I> for I
 	fn stream(self) -> impl Stream<Item = <I as IntoIterator>::Item> + Send { stream::iter(self) }

 	#[inline]
-	fn try_stream(
+	fn try_stream<E>(
 		self,
 	) -> impl TryStream<
 		Ok = <I as IntoIterator>::Item,
-		Error = Error,
-		Item = Result<<I as IntoIterator>::Item, Error>,
+		Error = E,
+		Item = Result<<I as IntoIterator>::Item, E>,
 	> + Send {
 		self.stream().map(Ok)
 	}
--- a/src/core/utils/stream/try_broadband.rs
+++ b/src/core/utils/stream/try_broadband.rs
@@ -1,9 +1,10 @@
 //! Synchronous combinator extensions to futures::TryStream

+use std::result::Result;
+
 use futures::{TryFuture, TryStream, TryStreamExt};

 use super::automatic_width;
-use crate::Result;

 /// Concurrency extensions to augment futures::TryStreamExt. broad_ combinators
 /// produce out-of-order
--- a/src/service/announcements/mod.rs
+++ b/src/service/announcements/mod.rs
@@ -20,7 +20,6 @@
 use async_trait::async_trait;
 use conduwuit::{Result, Server, debug, error, warn};
 use database::{Deserialized, Map};
-use rand::Rng;
 use ruma::events::{Mentions, room::message::RoomMessageEventContent};
 use serde::Deserialize;
 use tokio::{
--- a/src/service/client/mod.rs
+++ b/src/service/client/mod.rs
@@ -39,7 +39,7 @@ fn build(args: crate::Args<'_>) -> Result<Arc<Self>> {
 		let url_preview_user_agent = config
 			.url_preview_user_agent
 			.clone()
-			.unwrap_or_else(|| conduwuit::version::user_agent().to_owned());
+			.unwrap_or_else(|| conduwuit::version::user_agent_media().to_owned());

 		Ok(Arc::new(Self {
 			default: base(config)?
--- a/src/service/media/data.rs
+++ b/src/service/media/data.rs
@@ -170,6 +170,8 @@ pub(super) fn remove_url_preview(&self, url: &str) -> Result<()> {
 		Ok(())
 	}

+	pub(super) async fn clear_url_previews(&self) { self.url_previews.clear().await; }
+
 	pub(super) fn set_url_preview(
 		&self,
 		url: &str,
--- a/src/service/media/preview.rs
+++ b/src/service/media/preview.rs
@@ -37,6 +37,9 @@ pub async fn remove_url_preview(&self, url: &str) -> Result<()> {
 	self.db.remove_url_preview(url)
 }

+#[implement(Service)]
+pub async fn clear_url_previews(&self) { self.db.clear_url_previews().await; }
+
 #[implement(Service)]
 pub async fn set_url_preview(&self, url: &str, data: &UrlPreviewData) -> Result<()> {
 	let now = SystemTime::now()
--- a/src/service/mod.rs
+++ b/src/service/mod.rs
@@ -31,7 +31,7 @@
 pub mod sending;
 pub mod server_keys;
 pub mod sync;
-pub mod transaction_ids;
+pub mod transactions;
 pub mod uiaa;
 pub mod users;

--- a/src/service/rooms/auth_chain/mod.rs
+++ b/src/service/rooms/auth_chain/mod.rs
@@ -142,7 +142,7 @@ async fn get_auth_chain_outer(

 	let chunk_cache: Vec<_> = chunk
 		.into_iter()
-		.try_stream()
+		.try_stream::<conduwuit::Error>()
 		.broad_and_then(|(shortid, event_id)| async move {
 			if let Ok(cached) = self.get_cached_eventid_authchain(&[shortid]).await {
 				return Ok(cached.to_vec());
--- a/src/service/services.rs
+++ b/src/service/services.rs
@@ -14,7 +14,7 @@
 	media, moderation, presence, pusher, registration_tokens, resolver, rooms, sending,
 	server_keys,
 	service::{self, Args, Map, Service},
-	sync, transaction_ids, uiaa, users,
+	sync, transactions, uiaa, users,
 };

 pub struct Services {
@@ -37,7 +37,7 @@ pub struct Services {
 	pub sending: Arc<sending::Service>,
 	pub server_keys: Arc<server_keys::Service>,
 	pub sync: Arc<sync::Service>,
-	pub transaction_ids: Arc<transaction_ids::Service>,
+	pub transactions: Arc<transactions::Service>,
 	pub uiaa: Arc<uiaa::Service>,
 	pub users: Arc<users::Service>,
 	pub moderation: Arc<moderation::Service>,
@@ -110,7 +110,7 @@ macro_rules! build {
 			sending: build!(sending::Service),
 			server_keys: build!(server_keys::Service),
 			sync: build!(sync::Service),
-			transaction_ids: build!(transaction_ids::Service),
+			transactions: build!(transactions::Service),
 			uiaa: build!(uiaa::Service),
 			users: build!(users::Service),
 			moderation: build!(moderation::Service),
--- a/src/service/transaction_ids/mod.rs
+++ b/src/service/transaction_ids/mod.rs
@@ -1,54 +0,0 @@
-use std::sync::Arc;
-
-use conduwuit::{Result, implement};
-use database::{Handle, Map};
-use ruma::{DeviceId, TransactionId, UserId};
-
-pub struct Service {
-	db: Data,
-}
-
-struct Data {
-	userdevicetxnid_response: Arc<Map>,
-}
-
-impl crate::Service for Service {
-	fn build(args: crate::Args<'_>) -> Result<Arc<Self>> {
-		Ok(Arc::new(Self {
-			db: Data {
-				userdevicetxnid_response: args.db["userdevicetxnid_response"].clone(),
-			},
-		}))
-	}
-
-	fn name(&self) -> &str { crate::service::make_name(std::module_path!()) }
-}
-
-#[implement(Service)]
-pub fn add_txnid(
-	&self,
-	user_id: &UserId,
-	device_id: Option<&DeviceId>,
-	txn_id: &TransactionId,
-	data: &[u8],
-) {
-	let mut key = user_id.as_bytes().to_vec();
-	key.push(0xFF);
-	key.extend_from_slice(device_id.map(DeviceId::as_bytes).unwrap_or_default());
-	key.push(0xFF);
-	key.extend_from_slice(txn_id.as_bytes());
-
-	self.db.userdevicetxnid_response.insert(&key, data);
-}
-
-// If there's no entry, this is a new transaction
-#[implement(Service)]
-pub async fn existing_txnid(
-	&self,
-	user_id: &UserId,
-	device_id: Option<&DeviceId>,
-	txn_id: &TransactionId,
-) -> Result<Handle<'_>> {
-	let key = (user_id, device_id, txn_id);
-	self.db.userdevicetxnid_response.qry(&key).await
-}
--- a/src/service/transactions/mod.rs
+++ b/src/service/transactions/mod.rs
@@ -0,0 +1,326 @@
+use std::{
+	collections::HashMap,
+	fmt,
+	sync::{
+		Arc,
+		atomic::{AtomicU64, Ordering},
+	},
+	time::{Duration, SystemTime},
+};
+
+use async_trait::async_trait;
+use conduwuit::{Error, Result, SyncRwLock, debug_warn, warn};
+use database::{Handle, Map};
+use ruma::{
+	DeviceId, OwnedServerName, OwnedTransactionId, TransactionId, UserId,
+	api::{
+		client::error::ErrorKind::LimitExceeded,
+		federation::transactions::send_transaction_message,
+	},
+};
+use tokio::sync::watch::{Receiver, Sender};
+
+use crate::{Dep, config};
+
+pub type TxnKey = (OwnedServerName, OwnedTransactionId);
+pub type WrappedTransactionResponse =
+	Option<Result<send_transaction_message::v1::Response, TransactionError>>;
+
+/// Errors that can occur during federation transaction processing.
+#[derive(Debug, Clone)]
+pub enum TransactionError {
+	/// Server is shutting down - the sender should retry the entire
+	/// transaction.
+	ShuttingDown,
+}
+
+impl fmt::Display for TransactionError {
+	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+		match self {
+			| Self::ShuttingDown => write!(f, "Server is shutting down"),
+		}
+	}
+}
+
+impl std::error::Error for TransactionError {}
+
+/// Minimum interval between cache cleanup runs.
+/// Exists to prevent thrashing when the cache is full of things that can't be
+/// cleared
+const CLEANUP_INTERVAL_SECS: u64 = 30;
+
+#[derive(Clone, Debug)]
+pub struct CachedTxnResponse {
+	pub response: send_transaction_message::v1::Response,
+	pub created: SystemTime,
+}
+
+/// Internal state for a federation transaction.
+/// Either actively being processed or completed and cached.
+#[derive(Clone)]
+enum TxnState {
+	/// Transaction is currently being processed.
+	Active(Receiver<WrappedTransactionResponse>),
+
+	/// Transaction completed and response is cached.
+	Cached(CachedTxnResponse),
+}
+
+/// Result of atomically checking or starting a federation transaction.
+pub enum FederationTxnState {
+	/// Transaction already completed and cached
+	Cached(send_transaction_message::v1::Response),
+
+	/// Transaction is currently being processed by another request.
+	/// Wait on this receiver for the result.
+	Active(Receiver<WrappedTransactionResponse>),
+
+	/// This caller should process the transaction (first to request it).
+	Started {
+		receiver: Receiver<WrappedTransactionResponse>,
+		sender: Sender<WrappedTransactionResponse>,
+	},
+}
+
+pub struct Service {
+	services: Services,
+	db: Data,
+	federation_txn_state: Arc<SyncRwLock<HashMap<TxnKey, TxnState>>>,
+	last_cleanup: AtomicU64,
+}
+
+struct Services {
+	config: Dep<config::Service>,
+}
+
+struct Data {
+	userdevicetxnid_response: Arc<Map>,
+}
+
+#[async_trait]
+impl crate::Service for Service {
+	fn build(args: crate::Args<'_>) -> Result<Arc<Self>> {
+		Ok(Arc::new(Self {
+			services: Services {
+				config: args.depend::<config::Service>("config"),
+			},
+			db: Data {
+				userdevicetxnid_response: args.db["userdevicetxnid_response"].clone(),
+			},
+			federation_txn_state: Arc::new(SyncRwLock::new(HashMap::new())),
+			last_cleanup: AtomicU64::new(0),
+		}))
+	}
+
+	async fn clear_cache(&self) {
+		let mut state = self.federation_txn_state.write();
+		// Only clear cached entries, preserve active transactions
+		state.retain(|_, v| matches!(v, TxnState::Active(_)));
+	}
+
+	fn name(&self) -> &str { crate::service::make_name(std::module_path!()) }
+}
+
+impl Service {
+	/// Returns the count of currently active (in-progress) transactions.
+	#[must_use]
+	pub fn txn_active_handle_count(&self) -> usize {
+		let state = self.federation_txn_state.read();
+		state
+			.values()
+			.filter(|v| matches!(v, TxnState::Active(_)))
+			.count()
+	}
+
+	pub fn add_client_txnid(
+		&self,
+		user_id: &UserId,
+		device_id: Option<&DeviceId>,
+		txn_id: &TransactionId,
+		data: &[u8],
+	) {
+		let mut key = user_id.as_bytes().to_vec();
+		key.push(0xFF);
+		key.extend_from_slice(device_id.map(DeviceId::as_bytes).unwrap_or_default());
+		key.push(0xFF);
+		key.extend_from_slice(txn_id.as_bytes());
+
+		self.db.userdevicetxnid_response.insert(&key, data);
+	}
+
+	pub async fn get_client_txn(
+		&self,
+		user_id: &UserId,
+		device_id: Option<&DeviceId>,
+		txn_id: &TransactionId,
+	) -> Result<Handle<'_>> {
+		let key = (user_id, device_id, txn_id);
+		self.db.userdevicetxnid_response.qry(&key).await
+	}
+
+	/// Atomically gets a cached response, joins an active transaction, or
+	/// starts a new one.
+	pub fn get_or_start_federation_txn(&self, key: TxnKey) -> Result<FederationTxnState> {
+		// Only one upgradable lock can be held at a time, and there aren't any
+		// read-only locks, so no point being upgradable
+		let mut state = self.federation_txn_state.write();
+
+		// Check existing state for this key
+		if let Some(txn_state) = state.get(&key) {
+			return Ok(match txn_state {
+				| TxnState::Cached(cached) => FederationTxnState::Cached(cached.response.clone()),
+				| TxnState::Active(receiver) => FederationTxnState::Active(receiver.clone()),
+			});
+		}
+
+		// Check if another transaction from this origin is already running
+		let has_active_from_origin = state
+			.iter()
+			.any(|(k, v)| k.0 == key.0 && matches!(v, TxnState::Active(_)));
+
+		if has_active_from_origin {
+			debug_warn!(
+				origin = ?key.0,
+				"Got concurrent transaction request from an origin with an active transaction"
+			);
+			return Err(Error::BadRequest(
+				LimitExceeded { retry_after: None },
+				"Still processing another transaction from this origin",
+			));
+		}
+
+		let max_active_txns = self.services.config.max_concurrent_inbound_transactions;
+
+		// Check if we're at capacity
+		if state.len() >= max_active_txns
+			&& let active_count = state
+				.values()
+				.filter(|v| matches!(v, TxnState::Active(_)))
+				.count() && active_count >= max_active_txns
+		{
+			warn!(
+				active = active_count,
+				max = max_active_txns,
+				"Server is overloaded, dropping incoming transaction"
+			);
+			return Err(Error::BadRequest(
+				LimitExceeded { retry_after: None },
+				"Server is overloaded, try again later",
+			));
+		}
+
+		// Start new transaction
+		let (sender, receiver) = tokio::sync::watch::channel(None);
+		state.insert(key, TxnState::Active(receiver.clone()));
+
+		Ok(FederationTxnState::Started { receiver, sender })
+	}
+
+	/// Finishes a transaction by transitioning it from active to cached state.
+	/// Additionally may trigger cleanup of old entries.
+	pub fn finish_federation_txn(
+		&self,
+		key: TxnKey,
+		sender: Sender<WrappedTransactionResponse>,
+		response: send_transaction_message::v1::Response,
+	) {
+		// Check if cleanup might be needed before acquiring the lock
+		let should_try_cleanup = self.should_try_cleanup();
+
+		let mut state = self.federation_txn_state.write();
+
+		// Explicitly set cached first so there is no gap where receivers get a closed
+		// channel
+		state.insert(
+			key,
+			TxnState::Cached(CachedTxnResponse {
+				response: response.clone(),
+				created: SystemTime::now(),
+			}),
+		);
+
+		if let Err(e) = sender.send(Some(Ok(response))) {
+			debug_warn!("Failed to send transaction response to waiting receivers: {e}");
+		}
+
+		// Explicitly close
+		drop(sender);
+
+		// This task is dangling, we can try clean caches now
+		if should_try_cleanup {
+			self.cleanup_entries_locked(&mut state);
+		}
+	}
+
+	pub fn remove_federation_txn(&self, key: &TxnKey) {
+		let mut state = self.federation_txn_state.write();
+		state.remove(key);
+	}
+
+	/// Checks if enough time has passed since the last cleanup to consider
+	/// running another. Updates the last cleanup time if returning true.
+	fn should_try_cleanup(&self) -> bool {
+		let now = SystemTime::now()
+			.duration_since(SystemTime::UNIX_EPOCH)
+			.expect("SystemTime before UNIX_EPOCH")
+			.as_secs();
+		let last = self.last_cleanup.load(Ordering::Relaxed);
+
+		if now.saturating_sub(last) >= CLEANUP_INTERVAL_SECS {
+			// CAS: only update if no one else has updated it since we read
+			self.last_cleanup
+				.compare_exchange(last, now, Ordering::Relaxed, Ordering::Relaxed)
+				.is_ok()
+		} else {
+			false
+		}
+	}
+
+	/// Cleans up cached entries based on age and count limits.
+	///
+	/// First removes all cached entries older than the configured max age.
+	/// Then, if the cache still exceeds the max entry count, removes the oldest
+	/// cached entries until the count is within limits.
+	///
+	/// Must be called with write lock held on the state map.
+	fn cleanup_entries_locked(&self, state: &mut HashMap<TxnKey, TxnState>) {
+		let max_age_secs = self.services.config.transaction_id_cache_max_age_secs;
+		let max_entries = self.services.config.transaction_id_cache_max_entries;
+
+		// First pass: remove all cached entries older than max age
+		let cutoff = SystemTime::now()
+			.checked_sub(Duration::from_secs(max_age_secs))
+			.unwrap_or(SystemTime::UNIX_EPOCH);
+
+		state.retain(|_, v| match v {
+			| TxnState::Active(_) => true, // Never remove active transactions
+			| TxnState::Cached(cached) => cached.created > cutoff,
+		});
+
+		// Count cached entries
+		let cached_count = state
+			.values()
+			.filter(|v| matches!(v, TxnState::Cached(_)))
+			.count();
+
+		// Second pass: if still over max entries, remove oldest cached entries
+		if cached_count > max_entries {
+			let excess = cached_count.saturating_sub(max_entries);
+
+			// Collect cached entries sorted by age (oldest first)
+			let mut cached_entries: Vec<_> = state
+				.iter()
+				.filter_map(|(k, v)| match v {
+					| TxnState::Cached(cached) => Some((k.clone(), cached.created)),
+					| TxnState::Active(_) => None,
+				})
+				.collect();
+			cached_entries.sort_by(|a, b| a.1.cmp(&b.1));
+
+			// Remove the oldest cached entries to get under the limit
+			for (key, _) in cached_entries.into_iter().take(excess) {
+				state.remove(&key);
+			}
+		}
+	}
+}
--- a/src/service/users/mod.rs
+++ b/src/service/users/mod.rs
@@ -184,6 +184,12 @@ pub async fn create(
 		password: Option<&str>,
 		origin: Option<&str>,
 	) -> Result<()> {
+		if !self.services.globals.user_is_local(user_id)
+			&& (password.is_some() || origin.is_some())
+		{
+			return Err!("Cannot create a nonlocal user with a set password or origin");
+		}
+
 		self.db
 			.userid_origin
 			.insert(user_id, origin.unwrap_or("password"));
Author	SHA1	Message	Date
timedout	69a08ffbf6	style: Make "empty timeline" warning only warn in debug mode	2026-02-23 21:36:13 +00:00
timedout	123aa2456c	perf: Delayed drop is probably unnecessary	2026-02-23 21:18:46 +00:00
timedout	c3f6c73ac4	feat: Add compile flag to instantly drop mutex for A/B testing	2026-02-23 20:58:22 +00:00
timedout	1730cc9ff3	fix: Write-lock individual rooms when building sync for them	2026-02-23 20:45:44 +00:00
Niklas Wojtkowiak	cb9786466b	chore(changelog): add news fragment for #1441	2026-02-23 17:59:13 +00:00
Niklas Wojtkowiak	18d2662b01	fix(config): remove allow_public_room_directory_without_auth	2026-02-23 17:59:13 +00:00
timedout	558262dd1f	chore: Refactor `transaction_ids` -> `transactions`	2026-02-23 17:44:35 +00:00
timedout	d311b87579	chore: Fix incorrect capitalisation I didn't realise I agreed to take an English class with @ginger while working on this server lol	2026-02-23 17:25:12 +00:00
timedout	8702f55cf5	fix: Don't panic if nobody's listening	2026-02-23 17:22:37 +00:00
timedout	d4481b07ac	chore: Add news frag	2026-02-23 16:54:54 +00:00
Jade Ellis	92351df925	refactor: Make federation transaction handle errors correctly We have a dedicated error type that's then matched. Event sorting is now infallible. Could probably be cleaned up in a bit.	2026-02-23 16:36:46 +00:00
Jade Ellis	47e2733ea1	refactor: Make stream utils generic over the error type	2026-02-23 16:36:46 +00:00
Jade Ellis	6637e4c6a7	fix: Clean up cache, prevent several race conditions We use one map which is only ever held for a short time.	2026-02-23 16:36:46 +00:00
nexy7574	35e441452f	feat: Attempt to build localised DAG before processing PDUs	2026-02-23 16:36:46 +00:00
nexy7574	66bbb655bf	feat: Warn when server is overloaded	2026-02-23 16:36:45 +00:00
nexy7574	81b202ce51	chore: Decrease transaction log verbosity	2026-02-23 16:36:45 +00:00
nexy7574	4657844d46	feat: Show active transaction handle count in `!admin federation incoming-federation`	2026-02-23 16:36:45 +00:00
nexy7574	9016cd11a6	chore: Run pre-commit and clippy to fix inherited CI errs	2026-02-23 16:36:45 +00:00
nexy7574	dd70094719	feat: Make `max_active_txns` actually configurable	2026-02-23 16:36:45 +00:00
nexy7574	fcd49b7ab3	fix: Remove duplicate fields from logs	2026-02-23 16:36:45 +00:00
nexy7574	470c9b52dd	feat: Instrument `process_inbound_transaction`	2026-02-23 16:36:45 +00:00
nexy7574	0d8cafc329	feat: Support casting transaction processing to the background	2026-02-23 16:36:44 +00:00
nexy7574	2f9956ddca	feat: Add helper functions for federation channels	2026-02-23 16:36:44 +00:00
nexy7574	21a97cdd0b	chore: Refactor existing references to transaction service	2026-02-23 16:36:44 +00:00
nexy7574	e986cd4536	feat(federation): Restructure transaction_ids service Adds two new in-memory maps to the service in to prepare for better handlers	2026-02-23 16:36:40 +00:00
Shane Jaroch	526d862296	fix: more aggressive user agent for URL preview adding "facebookexternalhit" alongside "embedbot" fixes many errors, such as YouTube Music's: "Your browser is deprecated. Please upgrade." add admin command to clear URL stuck and broken data (per URL currently) add command to clear all saved URL previews. sync resolver docs.	2026-02-23 15:24:14 +00:00
Ben Botwin	fbeb5bf186	report permission denied errors	2026-02-23 15:22:18 +00:00
Ben Botwin	a336f2df44	fixed formatting	2026-02-23 15:22:18 +00:00
Ben Botwin	19b78ec73e	made error handling more concise	2026-02-23 15:22:18 +00:00
Ben Botwin	27ff2d9363	added more granular error handling for other file fetch function	2026-02-23 15:22:18 +00:00
Ben Botwin	50fa8c3abf	ran format	2026-02-23 15:22:18 +00:00
Ben Botwin	18c4be869f	added handling for other potential errors	2026-02-23 15:22:18 +00:00
Ben Botwin	fc00b96d8b	Added proper 404 for not found media and fixed devshell for running tests	2026-02-23 15:22:18 +00:00
Jade Ellis	fa4156d8a6	docs: Changelog	2026-02-22 21:19:20 +00:00
Jade Ellis	23638cd714	feat(appservices): MSC3202 Device masquerading for appservices	2026-02-22 21:19:20 +00:00
Raven	9f1a483e76	docs: Add information about partnered homeservers to the introduction page & update README.md Includes step-by-step directions to ease the lift for those who have ended up here and who have never created a matrix account or used matrix before in the past. Also updates the information in README.md to match, as these should generally be identical.	2026-02-21 18:51:56 -08:00
Renovate Bot	688ef727e5	chore(deps): update rust crate nix to 0.31.0	2026-02-21 16:33:05 +00:00
Shannon Sterz	3de026160e	docs: express forbidden_remote_server_names as valid regex this field expects a regex not a glob, so the correct value should be "." if one wants to block all remote server names. otherwise, setting "" as documented results in an error on start because the configuration could not be properly parsed.	2026-02-21 16:27:59 +00:00
Ginger	9fe761513d	chore: Clippy & prek fixes	2026-02-21 11:27:39 -05:00
Renovate Bot	abf1e1195a	chore(deps): update rust crate libloading to 0.9.0	2026-02-21 01:55:48 +00:00
Ginger	d9537e9b55	fix: Forbid registering users with a non-local localpart	2026-02-20 20:54:19 -05:00
Jade Ellis	0d1de70d8f	fix(deps): Update lockfile	2026-02-21 00:22:42 +00:00
Ben Botwin	4aa03a71eb	fix(nix): Added unstable flag to buildDeps	2026-02-21 00:15:53 +00:00
aviac	f847918575	fix(nix): Fix `all-features` build The build was broken since we started using an unstable reqwest version which requires setting an extra feature flag	2026-02-21 00:15:53 +00:00
Renovate Bot	7569a0545b	chore(deps): update dependency lddtree to 0.5.0	2026-02-20 22:59:34 +00:00
				`@@ -0,0 +1 @@`
				`Improved the concurrency handling of federation transactions, vastly improving performance and reliability by more accurately handling inbound transactions and reducing the amount of repeated wasted work. Contributed by @nex and @Jade.`
				`@@ -0,0 +1 @@`
				`Added MSC3202 Device masquerading (not all of MSC3202). This should fix issues with enabling MSC4190 for some Mautrix bridges. Contributed by @Jade`
				`@@ -0,0 +1 @@`
				Removed the `allow_public_room_directory_without_auth` config option. Contributed by @0xnim.
				`@@ -0,0 +1 @@`
				Improved URL preview fetching with a more compatible user agent for sites like YouTube Music. Added `!admin media delete-url-preview <url>` command to clear cached URL previews that were stuck and broken.