pjsip/pjproject

Health v2 · maintenance only

Adoption not part of the score

2677 stars · 1006 forks observed · 2026-08-28

What it is AI-extracted, prompt v1, taxonomy v1, 2026-08-30, confidence not recorded

PJSIP is an open-source multimedia communication library written in C that implements SIP, SDP, RTP, STUN, TURN, and ICE protocols with high-level APIs in C, C++, Java, C#, and Python. It combines SIP signaling, audio/video media, and NAT traversal into a compact, portable API suitable for desktops, embedded systems, and mobile handsets.

Use cases

• build a SIP softphone for iOS and Android
• add VoIP calling with audio and video to an application
• implement SIP signaling with NAT traversal via STUN, TURN, and ICE
• embed real-time multimedia communication in an embedded or RTOS device
• create a SIP client with presence and instant messaging
• make peer-to-peer calls across NATs using ICE

When to choose

• you need a mature, standards-compliant SIP/RTP stack with NAT traversal in one library
• you are building a cross-platform VoIP or video-calling app including mobile
• you need a small-footprint library that runs on embedded systems
• you want high-level APIs in multiple languages over a C core

When to avoid

• you need WebRTC browser interoperability out of the box without extra work
• your project requires a permissive license since PJSIP is GPL-2.0 (commercial license available separately)
• you only need simple HTTP or messaging rather than real-time multimedia sessions
• you prefer a managed-language-only solution without native C compilation

Facets

library · maturity stable

http-client audio-processing video-processing networking sdk networking cross-platform developer-tools windows cross-platform embedded cpp c sip voip rtp nat-traversal stun turn ice multimedia-communication softphone real-time linux macos android ios

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