Telephony Engineer (FreeSWITCH, VoIP )

Hiring for a Client - Eureka Digitisation & Automation Services (eDAS)

Key Responsibilities

FreeSWITCH Core

• Install, configure, and maintain FreeSWITCH from scratch in production environments.
• Design and implement call flows, dialplans, IVRs, conferencing, and call routing with end-to-end ownership.
• Configure SIP internal/external profiles, gateways, trunks, and extensions.
• Implement multi-tenant and high-availability FreeSWITCH architectures.

SIP, RTP & Networking

• Work extensively with SIP signaling, RTP media, RTCP, and SDP negotiation.
• Troubleshoot one-way/no audio, call drops, registration failures, NAT traversal, and SIP/RTP issues.
• Configure NAT traversal, firewall rules, and RTP port ranges.
• Analyze SIP logs and traces using siptrace, sngrep, and tcpdump.

Dialplan & Scripting

• Develop FreeSWITCH dialplans using XML and scripting languages such as Lua, JavaScript, or Python.
• Implement:
• Inbound and outbound call queues
• Time-based routing
• Skill-based routing
• Failover and fallback logic

Integrations & APIs

• Integrate FreeSWITCH with CRM/ERP systems, billing platforms, AI voice bots (ASR/TTS), REST APIs, and WebSocket services.
• Work with Event Socket Library (ESL), including:
• Inbound & Outbound ESL
• Real-time call control and monitoring

WebRTC & Media

• Configure WebRTC using DTLS-SRTP, ICE, and OPUS.
• Work with mod_verto and SIP over WSS.
• Implement browser-based calling solutions.

Monitoring, Debugging & Production Support

• Monitor system performance and call quality.
• Analyze FreeSWITCH logs and CDRs.
• Optimize codec usage and RTP performance.
• Handle live production incidents, troubleshooting, and RCA.

Deployment & Operations

• Deploy and manage FreeSWITCH on Linux (CentOS/Ubuntu).
• Deploy on cloud platforms such as AWS, GCP, or Azure.
• Configure HA, load balancing, scaling, backups, and automation.
• Work with DevOps teams on CI/CD pipelines and production automation.

Mandatory Requirements

• 4+ years total experience, including 3+ years of hands-on FreeSWITCH implementation, configuration, and production support.
• Strong experience designing and implementing FreeSWITCH call flows, dialplans, IVRs, call routing, conferencing, SIP profiles, gateways, trunks, and extensions with end-to-end ownership.
• Strong hands-on knowledge of SIP, RTP, RTCP, SDP, and WebRTC, with the ability to troubleshoot call drops, one-way/no audio, registration failures, NAT traversal, and SIP/RTP issues.
• Hands-on experience developing FreeSWITCH dialplans using XML and at least one of Lua, JavaScript, or Python, including queues, time-based routing, skill-based routing, and failover logic.
• Experience integrating FreeSWITCH with CRM/ERP, REST APIs, WebSockets, AI Voice Bots (ASR/TTS), or billing platforms.
• Hands-on experience with ESL for real-time call control and monitoring.
• Strong Linux administration skills with experience deploying and managing FreeSWITCH on Ubuntu/CentOS.
• Proficiency in debugging using fs_cli, sngrep, and tcpdump.
• Working knowledge of MySQL/PostgreSQL, particularly for CDRs and reporting.
• Location: Candidate must be currently based in Delhi NCR only.
• Notice Period:Immediate joiners or candidates who can join within 15 days are highly preferred.

Preferred Requirements

• Experience with AWS, Azure, or GCP.
• Experience with High Availability, Load Balancing, CI/CD, automation, backups, and scalable FreeSWITCH deployments.
• Experience implementing WebRTC-based calling solutions, including mod_verto, SIP over WSS, DTLS-SRTP, ICE, and OPUS codec configuration.