SimpleX Chat iOS product specification. Bidirectional code links: product docs reference source files, source files reference product docs.

Related spec: spec/README.md | spec/architecture.md

Vision
Target Users
Capability Map
Navigation Map
Related Specifications

Executive Summary

SimpleX Chat is the first messaging platform with no user identifiers of any kind -- not even random numbers. It provides end-to-end encrypted messaging (with optional post-quantum cryptography), audio/video calls, file sharing, and group communication through a fully decentralized architecture where users control their own SMP relay servers. The iOS app is a native SwiftUI application backed by a Haskell core library.

Vision

SimpleX Chat is the first messaging platform that has no user identifiers -- not even random numbers. It uses double-ratchet end-to-end encryption with optional post-quantum cryptography. The system is fully decentralized with user-controlled SMP relay servers.

The protocol design ensures that no server or network observer can determine who communicates with whom. Each conversation uses separate unidirectional messaging queues on potentially different servers, and there is no shared identifier between the sender and receiver queues.

Target Users

Privacy-conscious individuals wanting secure messaging without phone-number or email-based identity
Groups and communities needing encrypted group communication with role-based access control
Users avoiding identity linkage who want to communicate without any persistent user identifier
Organizations needing self-hosted messaging infrastructure with full control over relay servers

Capability Map

1. Messaging

Core message composition, delivery, and interaction features.

Feature	Description	Key Source (Swift)
Text with markdown	Rich text formatting with SimpleX markdown syntax	`Shared/Views/Chat/ComposeMessage/ComposeView.swift`
Images	Compressed inline images (up to 255KB)	`Shared/Views/Chat/ChatItem/CIImageView.swift`
Video	Video message recording and playback	`Shared/Views/Chat/ChatItem/CIVideoView.swift`
Voice messages	Audio recording and playback (5min / 510KB limit)	`Shared/Views/Chat/ChatItem/CIVoiceView.swift`
File sharing	Files up to 1GB via XFTP protocol	`Shared/Views/Chat/ChatItem/CIFileView.swift`
Link previews	OpenGraph metadata extraction and display	`Shared/Views/Chat/ChatItem/CILinkView.swift`
Message reactions	Emoji reactions on sent/received messages	`Shared/Views/Chat/ChatItem/EmojiItemView.swift`
Message editing	Edit previously sent messages	`Shared/Views/Chat/ComposeMessage/ComposeView.swift`
Message deletion	Broadcast delete (for recipient) or internal-only delete	`Shared/Views/Chat/ChatItem/MarkedDeletedItemView.swift`
Timed messages	Self-destructing messages with configurable TTL	`Shared/Views/Chat/ChatItem/CIChatFeatureView.swift`
Quoted replies	Reply to specific messages with quote context	`Shared/Views/Chat/ComposeMessage/ContextItemView.swift`
Forwarding	Forward messages between chats	`Shared/Views/Chat/ChatItemForwardingView.swift`
Search	Full-text search within conversations	`Shared/Views/Chat/ChatView.swift`
Message reports	Report messages to group moderators	`Shared/Views/Chat/ChatView.swift`

2. Contacts

Establishing, managing, and verifying contacts.

Feature	Description	Key Source (Swift)
Add via SimpleX address	Connect using a SimpleX contact address	`Shared/Views/NewChat/NewChatView.swift`
Add via QR code	Scan QR code to establish connection	`Shared/Views/Chat/ScanCodeView.swift`
Contact requests	Accept or reject incoming contact requests	`Shared/Views/ChatList/ContactRequestView.swift`
Local aliases	Set private display names for contacts	`Shared/Views/Chat/ChatInfoView.swift`
Contact verification	Compare security codes out-of-band	`Shared/Views/Chat/VerifyCodeView.swift`
Blocking	Block contacts from sending messages	`Shared/Views/Chat/ChatInfoView.swift`
Incognito mode	Per-contact random profile generation	`Shared/Views/UserSettings/IncognitoHelp.swift`
Bot detection	Identify automated/bot contacts	`SimpleXChat/ChatTypes.swift`

3. Groups

Multi-party encrypted conversations with role-based management.

Feature	Description	Key Source (Swift)
Create groups	Create new group with initial members	`Shared/Views/NewChat/AddGroupView.swift`
Invite members	Invite by individual contact or link	`Shared/Views/Chat/Group/AddGroupMembersView.swift`
Member roles	Owner, admin, moderator, member, observer	`SimpleXChat/ChatTypes.swift`
Member admission	Queue-based admission with review workflow	`Shared/Views/Chat/Group/MemberAdmissionView.swift`
Group links	Shareable invite links for groups	`Shared/Views/Chat/Group/GroupLinkView.swift`
Business chat mode	Structured business communication groups	`Shared/Views/Chat/Group/GroupChatInfoView.swift`
Content moderation	Member reports and moderator actions	`Shared/Views/Chat/Group/MemberSupportView.swift`
Group preferences	Configure group-level feature settings	`Shared/Views/Chat/Group/GroupPreferencesView.swift`
Member direct contacts	Establish direct chats from group membership	`Shared/Views/Chat/Group/GroupMemberInfoView.swift`

4. Calling

End-to-end encrypted audio and video communication.

Feature	Description	Key Source (Swift)
E2E encrypted calls	Audio/video calls via WebRTC with E2E encryption	`Shared/Views/Call/WebRTCClient.swift`
CallKit integration	Native iOS system call UI (ring, answer, decline)	`Shared/Views/Call/CallController.swift`
Audio device switching	Switch between speaker, earpiece, Bluetooth	`Shared/Views/Call/CallAudioDeviceManager.swift`
Call history	Call events displayed as chat items	`Shared/Views/Chat/ChatItem/CICallItemView.swift`
Incoming call view	Dedicated UI for incoming call notifications	`Shared/Views/Call/IncomingCallView.swift`

5. Privacy & Security

Encryption, authentication, and privacy controls.

Feature	Description	Key Source (Swift)
E2E encryption	Double-ratchet encryption for all messages	`SimpleXChat/API.swift`
Post-quantum encryption	Optional PQ key exchange for direct chats	`SimpleXChat/ChatTypes.swift`
Local authentication	Face ID, Touch ID, or app passcode lock	`Shared/Views/LocalAuth/LocalAuthView.swift`
Hidden profiles	Password-protected profiles invisible in UI	`Shared/Views/UserSettings/HiddenProfileView.swift`
Database encryption	AES encryption of local SQLite database	`Shared/Views/Database/DatabaseEncryptionView.swift`
Screen privacy	Blur app content when in app switcher	`Shared/Views/UserSettings/PrivacySettings.swift`
Encrypted file storage	Local files encrypted at rest	`SimpleXChat/CryptoFile.swift`
Delivery receipts control	Toggle delivery/read receipts per contact/group	`Shared/Views/UserSettings/SetDeliveryReceiptsView.swift`

6. User Management

Multiple profiles and identity management.

Feature	Description	Key Source (Swift)
Multiple profiles	Multiple user profiles within one app	`Shared/Views/UserSettings/UserProfilesView.swift`
Active user switching	Switch between profiles via user picker	`Shared/Views/ChatList/UserPicker.swift`
Incognito contacts	Per-contact random identities	`Shared/Views/UserSettings/IncognitoHelp.swift`
Profile sharing	Share profile via contact address link	`Shared/Views/UserSettings/UserAddressView.swift`
User muting	Mute notifications for specific profiles	`Shared/Views/ChatList/UserPicker.swift`

7. Network

Server configuration, proxy support, and connectivity.

Feature	Description	Key Source (Swift)
Custom SMP servers	Configure personal SMP relay servers	`Shared/Views/UserSettings/NetworkAndServers/ProtocolServersView.swift`
Custom XFTP servers	Configure personal XFTP file servers	`Shared/Views/UserSettings/NetworkAndServers/ProtocolServersView.swift`
Tor/onion support	Route traffic through Tor .onion addresses	`Shared/Views/UserSettings/NetworkAndServers/AdvancedNetworkSettings.swift`
SOCKS5 proxy	Route connections through SOCKS5 proxy	`Shared/Views/UserSettings/NetworkAndServers/AdvancedNetworkSettings.swift`
Custom ICE servers	Configure WebRTC ICE/TURN servers	`Shared/Views/UserSettings/RTCServers.swift`
Network timeouts	Configure connection timeout parameters	`Shared/Views/UserSettings/NetworkAndServers/AdvancedNetworkSettings.swift`

8. Customization

Visual appearance and UI preferences.

Feature	Description	Key Source (Swift)
Themes	Light, dark, SimpleX, black, and custom themes	`Shared/Theme/ThemeManager.swift`
Wallpapers	Preset and custom chat wallpapers	`Shared/Views/Helpers/ChatWallpaper.swift`
Chat bubble styling	Customize message bubble appearance	`SimpleXChat/Theme/ThemeTypes.swift`
One-handed UI mode	Compact layout for single-hand use	`Shared/Views/ChatList/OneHandUICard.swift`
Language selection	In-app language override	`Shared/Views/UserSettings/AppearanceSettings.swift`

9. Data Management

Import, export, encryption, and storage management.

Feature	Description	Key Source (Swift)
Export/import profiles	Full database export and import	`Shared/Views/Database/DatabaseView.swift`
Database encryption	Encrypt/decrypt local database with passphrase	`Shared/Views/Database/DatabaseEncryptionView.swift`
Local file encryption	Encrypt stored media and attachments	`SimpleXChat/CryptoFile.swift`
Storage breakdown	View storage usage by category	`Shared/Views/UserSettings/StorageView.swift`
Device-to-device migration	Migrate full profile between iOS devices	`Shared/Views/Migration/MigrateFromDevice.swift`

10. Desktop Integration

Remote control of the mobile app from a desktop client.

Feature	Description	Key Source (Swift)
Remote control pairing	Pair with desktop app via QR code	`Shared/Views/RemoteAccess/ConnectDesktopView.swift`
Session management	Manage active desktop control sessions	`Shared/Views/RemoteAccess/ConnectDesktopView.swift`

Onboarding
  OnboardingView.swift
    -> SimpleXInfo -> CreateProfile -> ChooseServerOperators -> SetNotificationsMode -> CreateSimpleXAddress
    -> ChatListView (home)

ChatListView (home)
  Shared/Views/ChatList/ChatListView.swift
    -> ChatView .................. (tap conversation row)
    -> NewChatMenuButton ......... (+ button)
    -> SettingsView .............. (gear icon)
    -> UserPicker ................ (avatar tap)
    -> TagListView ............... (tag filter bar)
    -> ServersSummaryView ........ (server status)

ChatView
  Shared/Views/Chat/ChatView.swift
    -> ChatInfoView .............. (contact name tap, direct chat)
    -> GroupChatInfoView ......... (group name tap, group chat)
    -> ActiveCallView ............ (call button)
    -> ComposeView ............... (message input area)
    -> ChatItemInfoView .......... (long press -> info)
    -> ChatItemForwardingView .... (long press -> forward)
    -> SecondaryChatView ......... (member support thread)

ChatInfoView
  Shared/Views/Chat/ChatInfoView.swift
    -> ContactPreferencesView .... (preferences)
    -> VerifyCodeView ............ (verify security code)

GroupChatInfoView
  Shared/Views/Chat/Group/GroupChatInfoView.swift
    -> GroupProfileView .......... (edit profile)
    -> AddGroupMembersView ....... (invite members)
    -> GroupLinkView ............. (manage group link)
    -> MemberAdmissionView ....... (admission settings)
    -> GroupPreferencesView ...... (group feature settings)
    -> GroupMemberInfoView ....... (tap member)
    -> GroupWelcomeView .......... (welcome message)

NewChatMenuButton
  Shared/Views/NewChat/NewChatMenuButton.swift
    -> NewChatView ............... (QR scanner / paste link)
    -> AddGroupView .............. (create group)
    -> UserAddressView ........... (create SimpleX address)

SettingsView
  Shared/Views/UserSettings/SettingsView.swift
    -> AppearanceSettings ........ (themes, wallpapers, UI)
    -> NetworkAndServers ......... (SMP/XFTP/proxy config)
    -> PrivacySettings ........... (privacy toggles)
    -> NotificationsView ......... (push notification mode)
    -> DatabaseView .............. (export/import/encrypt)
    -> CallSettings .............. (call preferences)
    -> StorageView ............... (storage usage)
    -> VersionView ............... (about/version)
    -> DeveloperView ............. (developer options)

UserPicker
  Shared/Views/ChatList/UserPicker.swift
    -> UserProfilesView .......... (manage all profiles)
    -> UserAddressView ........... (SimpleX address)
    -> PreferencesView ........... (user preferences)
    -> SettingsView .............. (app settings)
    -> ConnectDesktopView ........ (pair with desktop)

concepts.md -- Feature concept index with bidirectional code links
glossary.md -- Domain term glossary
spec/README.md -- Technical specification overview
spec/architecture.md -- Architecture specification
Haskell core: ../../src/Simplex/Chat/Controller.hs, ../../src/Simplex/Chat/Types.hs
Swift model: Shared/Model/ChatModel.swift, SimpleXChat/ChatTypes.swift
Swift API bridge: SimpleXChat/API.swift, Shared/Model/SimpleXAPI.swift

README.md

SimpleX Chat iOS -- Product Overview

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