WebRTC Engineer – Real-time Media Stack

About the role

Join Threema’s real‑time media team to own and evolve the WebRTC stack that powers secure messaging, video meetings and screen sharing across web, desktop and mobile clients.

Key responsibilities

• Build and improve the WebRTC media pipeline across web, desktop, and mobile clients, including audio, video, screen sharing, and data channels.
• Develop and scale the Selective Forwarding Unit (SFU) and signaling services for large meetings, webinars, and breakout rooms.
• Tune congestion control, bandwidth estimation, simulcast, and SVC layer selection to adapt to poor networks.
• Own end‑to‑end call quality: define metrics, build dashboards, investigate issues with getStats, RTC logs, and packet traces, and ship fixes.
• Work on NAT traversal, STUN/TURN infrastructure, ICE behavior, and corporate network fallbacks.

Required profile

• 5+ years of software engineering experience, with at least 3 years focused on WebRTC or real‑time media systems.
• Deep understanding of the WebRTC stack (SDP, ICE, DTLS, SRTP) and practical experience integrating it.
• Experience building or operating an SFU/MCU, using open‑source projects such as mediasoup, Janus, Jitsi, Pion or LiveKit.
• Strong knowledge of audio and video codecs (Opus, VP8, VP9, AV1, H.264) and their trade‑offs.
• Proficiency in at least one language among C++, Kotlin, Go or Rust, plus comfort with TypeScript/JavaScript for browser work.

Required skills

• WebRTC, SDP, ICE, DTLS, SRTP
• SFU/MCU development (mediasoup, Janus, Jitsi, Pion, LiveKit)
• Audio/video codecs: Opus, VP8, VP9, AV1, H.264
• C++, Kotlin, Go, Rust
• TypeScript, JavaScript
• STUN/TURN, NAT traversal, ICE handling
• Insertable Streams / SFrame (optional)
• Kubernetes deployment (optional)

What we offer

• Young, motivated team with straightforward communication.
• Flexible working hours, up to two days per week remote and two‑week remote‑anywhere option.
• Choice of hardware (macOS or Linux).
• Public transport discount or parking with electric‑car charging.
• Fitness room, monthly trainer, professional massage, coffee machine.
• Company events, aperitifs, and the chance to protect millions of users’ privacy.