Permanent Hiring

Job Role - Telephony Engineer(Freeswitch Development)

Location - Gurgaon (WFO)

Exp Required - 4 To 8 Years

CTC Budget - 8 to 18 LPA

Job Summary

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.

Required Skills

Technical Skills

- Robust experience with FreeSWITCH
- Solid knowledge of VoIP protocols (SIP, RTP, RTCP, WebRTC)
- Linux system administration
- Dialplan development (XML/Lua/JS/Python)
- ESL & event-driven call control
- Debugging tools (fs_cli, sngrep, tcpdump)
- SQL / MySQL / PostgreSQL (CDR, reporting)

________________________________________

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:

oXML

oLua / JavaScript / Python

- Implement logic for:

oCall queues for inbound and outbound calls

oTime-based routing

oSkill-based routing

oFailover and fallback handling

________________________________________

Integrations & APIs

- Integrate FreeSWITCH with:

oCRM / ERP systems

oBilling platforms

oAI voice bots (ASR/TTS)

oExternal WebSocket or REST services

- Use Event Socket Library (ESL):

oInbound & Outbound ESL

oReal-time call control and monitoring

________________________________________

WebRTC & 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:

oLinux (CentOS / Ubuntu)

oCloud platforms (AWS / GCP / Azure preferred)

- Configure HA, load balancing, and scaling
- Work with DevOps teams for CI/CD, backups, and automation

________________________________________

Interested candidates please reach on Sonali - (phone hidden) OR Share updated profile on [email protected]

📌 Telephony Engineer(Freeswitch Development)_Gurgaon (Gurugram)
🏢 Lester Infoservices
📍 Gurugram