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# Staff Software Engineer

- **Company:** Mad Devs
- **Location:** UK (Remote available)
- **Experience:** Expert
- **Contract:** Permanent contract
- **Skills:** Artificial Intelligence, VoIP, Code Review, Network Congestion, Software Debugging, Software Design Documents, Disaster Recovery, Python (Programming Language), Pcap, Load Testing, Lua (Scripting Language), Public Switched Telephone Networks, Twilio, OpenSIPS, Real Time Systems, Kubernetes, Kamailio, Terraform
- **Published:** June 12, 2026
- **Apply:** https://uk.indeed.com/viewjob?jk=603c68a02f07501e

## About the Role

Do you have experience in VoIP?, * 8+ years engineering, 4+ years in telecom/VoIP in production

 * Technical leadership: design docs, mentoring, cross-team decisions
 * Deep production experience with FreeSWITCH + Kamailio OR OpenSIPS (custom modules, routing scripts, at scale)
 * Strong SIP/RTP/SRTP/SDP/ICE; debug via pcap and SIP trace
 * Operated voice platform at 1,000+ concurrent calls (knows diff to 10k)
 * Strong Python; can work in Lua/Go/C as needed
 * Production integration with PSTN/SIP trunk providers (Twilio, Telnyx, etc.), DID management, LCR
 * Hands-on HA/failover for real-time systems
 * Production Kubernetes (GKE/EKS) and Terraform
 * Language Proficiency: English at B2-C1 level, Russian at B2 level
 * Location: any, except Russia and Belarus

## Description

We are looking for Staff Software Engineer to set the technical direction for telecommunications platform. You will own the architecture of how calls enter, route through, and leave our system: SIP signaling at the edge (Kamailio / OpenSIPS), media and call control (FreeSWITCH, Asterisk, RTPengine), the Python services that bridge voice with our AI inference pipeline, and the carrier-facing integrations underneath.
VoIP
Lead
Python
Backend development
Senior, * Own end-to-end telecom architecture: SIP edge (Kamailio/OpenSIPS), media & call control (FreeSWITCH), Python services bridging voice to AI, carrier integrations

 * Scale platform to 10,000+ concurrent calls with tight latency/SLOs
 * Design HA/disaster recovery: anycast SIP, active/active media, geographic failover
 * Set engineering standards for telecom team (testing, load testing, code review, on-call)
 * Mentor senior/mid engineers, raise technical bar
 * Define voice quality observability & SLOs (MOS, jitter, packet loss, latency)
 * Lead carrier strategy: SIP trunk vendors, redundancy, LCR, STIR/SHAKEN
 * Partner with AI/product to keep latency budgets honest


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