Principal Software Engineer - Real-Time Voice

As Principal Software Engineer for Voice/VoIP, you'll own the technical direction of Parloa's real-time voice infrastructure — the systems that let AI agents have natural, low-latency phone conversations at enterprise scale, across telephony providers, carriers, and global markets. This is a hands-on technical leadership role where you'll set architectural direction, solve the hardest problems yourself, and raise the bar for how the wider engineering org builds and reasons about voice systems.

What you'll do

• Own the architecture and technical roadmap for Parloa's Voice/VoIP infrastructure, including SIP trunking, media handling, and real-time audio pipelines
• Design for low-latency, high-availability voice at enterprise scale — across global telephony carriers and providers
• Drive technical decisions on protocols and standards (SIP, SDP, RTP/SRTP, RTCP, WebRTC, ICE, STUN/TURN) and real-time media transport
• Partner with AI/ML teams to optimise the integration between voice infrastructure and conversational AI models (ASR, TTS, turn-taking, barge-in)
• Diagnose and resolve deep, systemic issues in call quality, latency, jitter, and packet loss across distributed, multi-region deployments
• Define and uphold engineering standards for reliability, observability, and security across the voice stack
• Mentor senior and staff engineers, acting as a technical multiplier across the organisation
• Evaluate and integrate with telephony providers, carriers, and SIP trunk vendors as Parloa expands into new markets

What you'll need

• 10+ years of engineering experience, including 5+ years hands-on building, operating, or debugging production Voice/VoIP, SIP, WebRTC, or carrier-grade voice infrastructure
• Strong knowledge of SIP, SDP, RTP/SRTP, RTCP, WebRTC, ICE, and real-time media transport protocols
• Hands-on understanding of audio codecs and media behavior, including Opus, G.711/G.722, codec negotiation/transcoding, DTMF/RFC2833, jitter buffers, packetization, and codec-related quality/latency trade-offs
• Experience building or operating large-scale, distributed, real-time systems with strict latency and availability requirements
• A track record of owning architecture for complex systems and driving technical decisions with broad organisational impact
• Deep, hands-on ownership of production SIP-based voice infrastructure at enterprise scale (e.g. Kamailio, FreeSWITCH, Asterisk, pjsip)
• Strong systems programming skills in one or more of Go, C, C++ or Rust, with the ability to work at the media/transport layer
• Comfort operating in cloud environments (AWS, GCP, or Azure) and with container orchestration (Kubernetes)

Nice to have

• Experience working with telephony carriers, SIP trunk providers, or PSTN integrations at scale
• Experience instrumenting and operating voice-quality observability — call-quality metrics (e.g. MOS), per-leg call tracing, and diagnosing jitter, latency, and packet loss from telemetry
• A genuine interest in AI and conversational technology, and how voice infrastructure underpins it

What they offer

• Hands-on technical leadership role with ownership of voice infrastructure architecture
• Work with leading global investors and backing from General Catalyst, EQT Ventures, and Altimeter Capital
• Opportunity to shape how businesses and customers connect at enterprise scale
• Direct impact on over one billion customer interactions globally