Lead/Senior VoIP Engineer

Synthflow AI is an enterprise AI agent platform that unifies customer operations across voice, chat, and messaging. Our agents handle routine interactions at scale so teams can focus on high-value work.

• Over 20M hours of operations automated

• 60% more calls answered vs. non-AI operators

• 150M interactions handled, 99.99% uptime

Backed by Accel, Atlantic Labs, and Singular. Trusted by 1,000+ customers. Recognized as one of the most promising companies in Germany.

We’re looking for a hands-on VoIP Engineer to help build, maintain, and improve our telephony infrastructure, with a focus on Kamailio and RTPEngine. You’ll work on SIP routing, media handling, and production troubleshooting to keep our voice services reliable and performant. This role is a good fit for someone with practical Kamailio and RTPEngine experience, working knowledge of FreeSWITCH, and strong Linux and SIP/RTP debugging skills.

Your Responsibilities

• Deploy, configure, and maintain Kamailio and RTPEngine

• Troubleshoot SIP signaling, RTP media, and call quality issues

• Support FreeSWITCH services and Linux-based telephony infrastructure

• Improve call routing, load balancing, failover, and monitoring

• Manage configurations in Git and document operational changes

What We’re Looking For

• Hands-on experience with Kamailio and RTPEngine

• Strong SIP/RTP debugging skills using tools like sngrep, tcpdump, or Wireshark

• Working knowledge of FreeSWITCH

• Solid Linux administration and networking skills

• Experience with Git and collaborative change management

• Nice to have: GCP, Kubernetes, Python or Go, and Bash scripting

Founded in Berlin in 2023 by serial entrepreneurs Albert Astabatsyan, Hakob Astabatsyan, and Sassun Mirzakhan-Saky, Synthflow AI democratizes access to advanced voice AI with a no-code platform that lets enterprises easily create, deploy and scale natural-sounding, cost-effective voice agents tailored to their business needs.