Lead Telephony Engineer

Location: Portugal (PT)

Experience Level: Senior

Description

We're expanding the team and are looking for a Telephony Engineer.

Requirements

• 5 to 10 years of experience in VoIP and telephony engineering
• Deep understanding of SIP protocol including messaging, methods, response codes and SDP, as well as troubleshooting of signaling and media issues including NAT and RTP
• Knowledge of FreeSWITCH/Asterisk/ or any other b2ua including architecture, dialplan development using Lua/XML/conf, configuration of SIP profiles, gateways and modules, performance optimization
• Experience building utilities, tools, management services for VoIP infrastructure
• Experience with any kind of programming language.
• Solid understanding of networking including TCP IP, RTP RTCP and traffic analysis using tools such as tcpdump, Wireshark and sngrep
• Strong Linux administration (Debian or Ubuntu)

Nice to have

• Experience with Go language.
• Experience with Kamailio/Opensips or rtpengine
• Familiarity with CI CD, Docker, Ansible and Kubernetes
• Experience with large scale telephony systems
• Experience with ESL and Sofia knowledge
• Experience with Node.js for integration services, event socket (ESL) interaction with FreeSWITCH and REST API development
• Background in voice biometrics projects

Responsibilities

• Design and modernization of the telephony infrastructure
• Integration with telecom providers in the US, LATAM and Europe
• Optimization of resources and telecom costs
• Building call handling systems from scratch for both outbound and inbound traffic
• Development of integration solutions with the AI platform
• Driving reliability, scaling and fault tolerance
• Working with high call volumes using Kamailio/OpenSIPS and rtpengine
• Participate in 2d and 3d level support duties as well as on-call rotation

What we offer

• The team has built award-winning AI products for tech corporations — devices, voice assistants, products that are actually in the world 
• Cutting-edge tech stack: Speech Technologies, NLP, Generative AI (LLMs, diffusion models), voice-first agentic architecture with privacy-first and on-premises deployment
• High engineering bar and real ownership — the team cares about what actually works in production, not what looks good in a demo, and you'll see the impact of your work directly 
• Fast career progression — a senior-heavy team and a high volume of real problems means you grow faster than you would anywhere else 
• Startup pace with enterprise stability — real clients, real revenue, no bureaucracy 
• Fully remote across Europe
• 21 vacation days + public holidays + 5 sick days 
• Private English lessons via Preply