Telephony Engineer(Freeswitch Development)_Gurgaon

Lester Infoservices; Gurugram District; On-site; INR 800,000 - 1,800,000; Full time

Job summary

Lester Infoservices in Gurgaon is seeking a FreeSWITCH Implementation Engineer to design, deploy, configure, integrate, and maintain FreeSWITCH-based VoIP platforms in production. You will work with SIP, RTP, WebRTC, IVR, conferencing, and call routing with responsibility from end to end.

The role requires 4–8 years of hands-on experience, Linux administration, and strong scripting and integration skills. WFO in Gurgaon with opportunities to work on multi-tenant, HA FreeSWITCH architectures.

Qualifications

• 4–8 years of hands-on FreeSWITCH development and deployment experience.
• Strong knowledge of SIP/RTP/WebRTC and VoIP protocols.
• Experience in dialplan development (XML/Lua/JS/Python) on Linux.
• Ability to design HA FreeSWITCH architectures and multi-tenant setups.

Responsibilities

• Install, configure, and maintain FreeSWITCH in production environments from scratch.
• Design and implement call flows, dialplans, IVRs, conferencing, and call routing with complete ownership.
• Configure SIP profiles, gateways, trunks, and extensions.
• Implement multi-tenant and high-availability FreeSWITCH architectures.
• Troubleshoot SIP signaling, RTP, and network issues; analyze logs and traces.
• Develop dialplans using XML, Lua/JavaScript/Python; implement queues, time-based routing, and skill-based routing.

Skills

FreeSWITCH

VoIP protocols

Linux admin

Dialplan XML/Lua/JS/Python

ESL & event-driven

Debugging tools

SQL / MySQL / PostgreSQL

Tools

fs_cli

sngrep

tcpdump

Job description

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

• Strong 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:
  • XML
  • Lua / JavaScript / Python
• Implement logic for:
  • Call queues for inbound and outbound calls
  • Time-based routing
  • Skill-based routing
  • Failover and fallback handling

Integrations & APIs

• Integrate FreeSWITCH with:
  • CRM / ERP systems
  • Billing platforms
  • AI voice bots (ASR/TTS)
  • External WebSocket or REST services
• Use Event Socket Library (ESL):
  • Inbound & Outbound ESL
  • Real-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:
  • Linux (CentOS / Ubuntu)
  • Cloud 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 - 8879984232 OR Share updated profile on [e-mail]