Lead VOIP Engineer (FreeSWITCH & Kamailio)
Synthflow AIBerlin, Germany
Posted November 4, 2025
Full Time
About the Company
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.
Job Description
We are seeking an experienced VOIP Engineer with a strong background in FreeSWITCH and Kamailio to join our team. The ideal candidate will have extensive experience in SIP-based communications, RTP streaming, and conferencing solutions, along with a deep understanding of high-load production environments.
Requirements
- 5+ years of experience in VOIP engineering, particularly with FreeSWITCH and Kamailio
- Strong expertise in SIP protocol, RTP streaming, and VoIP call flows
- Experience working in high-load production FreeSWITCH environments
- Hands-on experience with Homer SIP capture or similar SIP monitoring tools
- Deep understanding of NAT traversal, STUN/TURN, WebRTC, and ICE frameworks
- Strong knowledge of load balancing, failover strategies, and traffic optimization
- Proficiency in Linux administration, networking, and troubleshooting
- Experience with database integration (Redis, PostgreSQL, or NoSQL solutions)
- Familiarity with WebRTC, Asterisk, OpenSIPS, or RTP Proxy is a plus
- Ability to write Bash/Python (or Golang) scripts for automation and monitoring
- Strong problem-solving skills and ability to work in highly available and scalable environments
