Telephony Engineer - VoIP/FreeSWITCH

Job Description :We are looking for a FreeSWITCH Implementation Engineer who will be responsible for designing, deploying, configuring, integrating, and maintaining FreeSWITCH-based VoIP platforms. The role involves working closely with SIP, RTP, WebRTC, IVR, conferencing, call routing, and external integrations in a production environment.Key Responsibilities :FreeSWITCH Core Responsibilities :- Install, configure, and maintain FreeSWITCH in production environments from the scratch.- Design and implement call flows, dialplans, IVRs, conferencing, and call routing with complete ownership.- Configure SIP profiles (internal/external), gateways, trunks, and extensions.- Implement multi-tenant and high-availability FreeSWITCH architectures.SIP, RTP & Networking :- Strong understanding of SIP signaling, RTP media, and SDP negotiation.- Troubleshoot one-way audio, no-audio, call drops, registration failures.- Configure NAT traversal, firewall rules, and RTP port ranges.- Analyze SIP logs and traces (siptrace, sngrep, tcpdump).Dialplan & Scripting :- Develop dialplans using:1. XML2. Lua / JavaScript / Python- Implement logic for:1. Call queues for inbound and outbound calls2. Time-based routing3. Skill-based routing4. Failover and fallback handlingIntegrations & APIs :- Integrate FreeSWITCH with:1. CRM / ERP systems2. Billing platforms3. AI voice bots (ASR/TTS)4. External WebSocket or REST services- Use Event Socket Library (ESL):1. Inbound & Outbound ESL2. Real-time call control and monitoringWebRTC & Media:- Configure WebRTC support (DTLS-SRTP, ICE, OPUS).- Work with mod_verto, SIP over WSS.- Implement browser-based calling solutions.Monitoring & Debugging:- Monitor system performance and call quality.- Analyze logs and CDRs.- Optimize codec usage and RTP performance.- Handle live production incidents and RCA.Deployment & Operations :- Deploy FreeSWITCH on:1. Linux (CentOS / Ubuntu)2. Cloud platforms (AWS / GCP / Azure preferred)- Configure HA, load balancing, and scaling.- Work with DevOps teams for CI/CD, backups, and automation.Requirements :- Must have minimum 4+ years experience, with at least 3+ years of hands-on experience implementing, configuring, and supporting FreeSWITCH in production environments.- Must have strong experience in designing and implementing FreeSWITCH call flows, including dialplans, IVRs, call routing, conferencing, SIP profiles, gateways, trunks, and extensions with end-to-end ownership.- Must have strong hands-on knowledge of VoIP technologies, including SIP, RTP, RTCP, SDP, WebRTC, and should be capable of troubleshooting call drops, one-way audio, registration failures, NAT traversal, and SIP/RTP-related issues.- Must have hands-on experience developing FreeSWITCH dialplans using XML and at least one scripting language such as Lua, JavaScript, or Python, including implementation of call queues, time-based routing, skill-based routing, and failover logic.- Must have experience integrating FreeSWITCH with CRM/ERP systems, REST APIs, WebSockets, AI Voice Bots (ASR/TTS), or Billing Platforms, along with hands-on experience using Event Socket Library (ESL) for real-time call control.- Must have strong Linux administration experience and should be comfortable deploying and managing FreeSWITCH on Ubuntu/CentOS, along with debugging using fs_cli, sngrep, tcpdump, and working with SQL (MySQL/PostgreSQL) for CDRs and reporting.- Immediate Joiners or candidates who can join within 15 days will be highly preferred.- Mandatory (Location) Candidate must be currently based in Delhi NCR only. (ref:hirist.tech)