Senior Software Engineer, Real-Time Communications

The role

You will own the production voice path end to end, including SIP signaling, media, and carrier trunks. You will design WebRTC handset integration and write routing logic for Kamailio, FreeSWITCH, and a TypeScript control plane.

What you will do

• Own the production voice path end to end
• Design how WebRTC handsets join the path
• Write the routing logic and dialplans
• Review call-path changes and author Sipfront and SIPp scenarios
• Produce packet-level truth about call quality
• Model and load-test call capacity
• Extend calling into new countries
• Harden the path with SIP over TLS, SRTP, rate limiting, and toll-fraud prevention
• Make the stack legible through documentation, runbooks, and reviews

Required qualifications

• 5+ years building and operating real-time voice or video systems in production
• Deep in SIP and RTP on a production stack
• Experience with registration, dialog state, NAT traversal, codecs and jitter buffers
• Ability to take a live production call from a packet capture to root cause
• At home in production code as well as config
• Fluency using AI as a multiplier across diagnosis, analysis, and testing
• Clear communicator who writes things down
• Collaborative, low-ego approach
• Based in Seattle and ready to work from our office Monday through Thursday

Nice to have

• Kamailio
• FreeSWITCH
• rtpengine
• WebRTC internals and bridging WebRTC to SIP
• Homer/HEP
• E911 or carrier interconnect
• STIR/SHAKEN

About the company

Tin Can is building a safer, simpler way for kids to connect without smartphones through screen-free devices and services. They are building a brand that resonates with folks who want something simpler and better for their kids.