flutter_sip_ua 1.0.1

Pure-Dart SIP user agent for the dart-pbx server (signalling only).

flutter_sip_ua

Pure-Dart SIP user agent and Flutter client for the dart-pbx server. The UI is modelled on InnovateAsterisk Browser-Phone with a Riverpod-driven state layer and a modular widget tree.

Repository: https://github.com/KellyKinyama/flutter_sip_ua

Features

• Pure-Dart SIP signalling stack (lib/sip/) — registration, calls, MESSAGE, digest auth, SDP, RTP/RTCP helpers.
• Pure-Dart media path — G.711 codec, RTP packetizer, jitter buffer. No flutter_webrtc, no libwebrtc binary.
• Multiple transports out of the box: WS/WSS, UDP, and optional RTP-over-QUIC datagrams (pure_dart_quic).
• Riverpod-based state management (lib/providers/sip_providers.dart).
• Browser-Phone-style UI:
  • Two-pane shell with buddy sidebar + active stream.
  • Modular call screen (lib/ui/widgets/call/).
  • Dialer sheet, message composer, transfer sheet.
• Light and dark themes that mirror phone.light.css / phone.dark.css. Theme choice is persisted via SharedPreferences and toggled from the sidebar toolbar (system → light → dark).

Why not dart-sip-ua + flutter_webrtc?

dart-sip-ua is a JsSIP port that delegates all media to flutter_webrtc, which bundles libwebrtc — roughly 10M lines of C++ extracted from Chromium, shipped as tens of megabytes of native binaries per platform. flutter_sip_ua keeps the entire stack — signalling, transport, RTP, codecs — in pure Dart, targeting the same capability surface as dart-webrtc without the native dependency.

	dart-sip-ua + flutter_webrtc	flutter_sip_ua
Language end-to-end	Dart + ~10M LOC C++ (libwebrtc)	Pure Dart
Binary footprint	Tens of MB of native libs per ABI/platform	Kilobytes
Native toolchain	NDK / CocoaPods / MSVC / depot_tools	None
Web support	Browser's WebRTC (different impl)	Same Dart code
Transports	WS / WSS only	WS / WSS / UDP / QUIC datagrams (TCP/TLS/SCTP pluggable)
Memory safety	C++ attack surface	Dart, memory-safe
Debuggability	RTC_LOG + Chromium source	Set a breakpoint

Transports beyond WebSockets

dart-sip-ua is effectively WebSocket-only — a browser-era constraint inherited from JsSIP. flutter_sip_ua ships:

• WS / WSS via web_socket_channel (works on dart:io and web).
• UDP via RawDatagramSocket (lib/sip/transport_udp_io.dart) — talk directly to Asterisk / FreeSWITCH / Kamailio on :5060 with no WS gateway.
• RTP-over-QUIC datagrams via pure_dart_quic — multiplexed, congestion-controlled, NAT/firewall-friendly.
• A pluggable transport interface so TCP, TLS, SCTP, or WebTransport can be added without native plugin work.

Current state vs. roadmap

Today: G.711 audio, RTP/RTCP, jitter buffer, SIP REGISTER / INVITE / MESSAGE, RFC 2617 digest, WS/WSS/UDP, optional QUIC datagrams.

Planned (pure-Dart parity with dart-webrtc): ICE / STUN / TURN, DTLS-SRTP, Opus, video codecs (VP8 / H.264), data channels, AEC / AGC.

dart-sip-ua + flutter_webrtc is more battle-tested today because it inherits everything from libwebrtc. flutter_sip_ua is the better fit when you want a small, auditable, web-friendly client that speaks to a real SIP server without dragging a Chromium-derived binary into your app.

Getting started

flutter pub get
flutter run -d windows   # or chrome / android / ios / linux / macos

Tests:

flutter test

Project layout

lib/
  main.dart
  providers/sip_providers.dart   # Riverpod facade over the SIP UA + UI state
  sip/                           # Pure-Dart SIP UA, SDP, transport, audio/video
  ui/
    theme.dart                   # Light/dark ThemeData built from BP palette
    bp_palette.dart              # Browser-Phone color tokens + ThemeExtension
    home_page.dart               # Two-pane shell + dialer sheet
    call_page.dart               # Slim call orchestrator
    widgets/
      buddy_sidebar.dart         # Left rail incl. theme toggle
      dial_pad.dart
      dialer_action_row.dart
      call/                      # Modular call UI pieces

Links

• Source: https://github.com/KellyKinyama/flutter_sip_ua
• Issues: https://github.com/KellyKinyama/flutter_sip_ua/issues
• Browser-Phone reference: https://github.com/InnovateAsterisk/Browser-Phone