diff --git a/platformio.ini b/platformio.ini
index 6c012f1e5..d47869081 100644
--- a/platformio.ini
+++ b/platformio.ini
@@ -177,7 +177,7 @@ build_flags = -std=c++17
   -I src
   -I test/mocks
 test_build_src = yes
-test_ignore = test_kiss_modem
+test_ignore = test_kiss_modem, test_ota_channel
 build_src_filter =
   -<*>
   +<../src/Utils.cpp>
@@ -203,3 +203,19 @@ build_src_filter =
 lib_deps =
   google/googletest @ 1.17.0
   bblanchon/ArduinoJson @ 7.4.3
+
+[env:native_ota_channel]
+platform = native
+test_framework = googletest
+build_flags = -std=c++17
+  -I test/mocks
+  -I src
+  -DOTA_MANIFEST_BASE="\"https://stable.example/mqtt/v\""
+  -DOTA_MANIFEST_BASE_STABLE="\"https://stable.example/mqtt/v\""
+  -DOTA_MANIFEST_BASE_DEV="\"https://dev.example/mqtt/dev/v\""
+test_build_src = yes
+test_filter = test_ota_channel
+build_src_filter =
+  -<*>
+lib_deps =
+  google/googletest @ 1.17.0
diff --git a/src/helpers/OtaChannel.h b/src/helpers/OtaChannel.h
new file mode 100644
index 000000000..d589854bc
--- /dev/null
+++ b/src/helpers/OtaChannel.h
@@ -0,0 +1,62 @@
+#pragma once
+#include <stdint.h>
+#include <string.h>
+
+// OTA release-channel selector, persisted in NodePrefs::ota_channel.
+enum OtaChannel : uint8_t {
+  OTA_CH_NATIVE = 0,  // follow the channel this build was made for
+  OTA_CH_STABLE = 1,
+  OTA_CH_DEV    = 2,
+};
+
+// Resolve the effective manifest base URL for a channel selector.
+// build.sh injects the three bases as compile-time macros:
+//   OTA_MANIFEST_BASE        = this build's native channel (defined on every OTA build)
+//   OTA_MANIFEST_BASE_STABLE = stable channel
+//   OTA_MANIFEST_BASE_DEV    = dev channel
+// stable/dev fall back to the native base when their macro is undefined (legacy/local
+// builds that only define OTA_MANIFEST_BASE), so this never returns nullptr on an
+// OTA-capable build. On a non-OTA build it returns nullptr.
+static inline const char* ota_resolve_base(uint8_t channel) {
+#if defined(OTA_MANIFEST_BASE)
+  switch (channel) {
+    case OTA_CH_STABLE:
+#if defined(OTA_MANIFEST_BASE_STABLE)
+      return OTA_MANIFEST_BASE_STABLE;
+#else
+      return OTA_MANIFEST_BASE;
+#endif
+    case OTA_CH_DEV:
+#if defined(OTA_MANIFEST_BASE_DEV)
+      return OTA_MANIFEST_BASE_DEV;
+#else
+      return OTA_MANIFEST_BASE;
+#endif
+    case OTA_CH_NATIVE:
+    default:
+      return OTA_MANIFEST_BASE;
+  }
+#else
+  (void)channel;
+  return nullptr;
+#endif
+}
+
+// Human label for a selector (for the `ota branch` report).
+static inline const char* ota_channel_name(uint8_t channel) {
+  switch (channel) {
+    case OTA_CH_STABLE: return "stable";
+    case OTA_CH_DEV:    return "dev";
+    default:            return "native";
+  }
+}
+
+// Parse an `ota branch` argument. Returns true and sets *out on a known keyword
+// (stable|dev|default; "default" -> native); returns false and leaves *out untouched
+// otherwise.
+static inline bool ota_parse_channel(const char* arg, uint8_t* out) {
+  if (strcmp(arg, "stable") == 0)  { *out = OTA_CH_STABLE; return true; }
+  if (strcmp(arg, "dev") == 0)     { *out = OTA_CH_DEV;    return true; }
+  if (strcmp(arg, "default") == 0) { *out = OTA_CH_NATIVE; return true; }
+  return false;
+}
diff --git a/test/test_ota_channel/test_ota_channel.cpp b/test/test_ota_channel/test_ota_channel.cpp
new file mode 100644
index 000000000..699ffb70c
--- /dev/null
+++ b/test/test_ota_channel/test_ota_channel.cpp
@@ -0,0 +1,34 @@
+#include <gtest/gtest.h>
+#include "helpers/OtaChannel.h"
+
+// The three base URLs are provided as -D macros by the test env (see platformio.ini).
+TEST(OtaChannel, ResolvesNativeToBaseMacro) {
+  EXPECT_STREQ(ota_resolve_base(OTA_CH_NATIVE), "https://stable.example/mqtt/v");
+}
+TEST(OtaChannel, ResolvesStable) {
+  EXPECT_STREQ(ota_resolve_base(OTA_CH_STABLE), "https://stable.example/mqtt/v");
+}
+TEST(OtaChannel, ResolvesDev) {
+  EXPECT_STREQ(ota_resolve_base(OTA_CH_DEV), "https://dev.example/mqtt/dev/v");
+}
+TEST(OtaChannel, ParseKnownKeywords) {
+  uint8_t ch = 99;
+  EXPECT_TRUE(ota_parse_channel("stable", &ch));  EXPECT_EQ(ch, OTA_CH_STABLE);
+  EXPECT_TRUE(ota_parse_channel("dev", &ch));     EXPECT_EQ(ch, OTA_CH_DEV);
+  EXPECT_TRUE(ota_parse_channel("default", &ch)); EXPECT_EQ(ch, OTA_CH_NATIVE);
+}
+TEST(OtaChannel, ParseRejectsUnknownAndLeavesOutputUntouched) {
+  uint8_t ch = 7;
+  EXPECT_FALSE(ota_parse_channel("beta", &ch));
+  EXPECT_EQ(ch, 7);
+}
+TEST(OtaChannel, NameLabels) {
+  EXPECT_STREQ(ota_channel_name(OTA_CH_NATIVE), "native");
+  EXPECT_STREQ(ota_channel_name(OTA_CH_STABLE), "stable");
+  EXPECT_STREQ(ota_channel_name(OTA_CH_DEV), "dev");
+}
+
+int main(int argc, char** argv) {
+  ::testing::InitGoogleTest(&argc, argv);
+  return RUN_ALL_TESTS();
+}