Telephony Engineer (FreeSWITCH, VoIP )

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:

o XML

o Lua / JavaScript / Python

Implement logic for:

o Call queues for inbound and outbound calls

o Time-based routing

o Skill-based routing

o Failover and fallback handling

Integrations & APIs

Integrate FreeSWITCH with:

o CRM / ERP systems

o Billing platforms

o AI voice bots (ASR/TTS)

o External WebSocket or REST services

Use Event Socket Library (ESL):

o Inbound & Outbound ESL

o 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:

o Linux (CentOS / Ubuntu)

o Cloud platforms (AWS / GCP / Azure – preferred)

Configure HA, load balancing, and scaling

Work with DevOps teams for CI/CD, backups, and automation

• Strong FreeSWITCH Implementation Engineer Profiles
• Mandatory (Experience 1) – Must have minimum 4+ years experience, with at least 3+ years of hands-on experience implementing, configuring, and supporting FreeSWITCH in production environments.
• Mandatory (Experience 2) – 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.
• Mandatory (Experience 3) – 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.
• Mandatory (Experience 4) – 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.
• Mandatory (Experience 5) – 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.
• Mandatory (Experience 6) – 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.
• Mandatory (Notice Period) – Immediate Joiners or candidates who can join within 15 days will be highly preferred.
• Preferred (Experience 1) – Experience with AWS, Azure, or GCP, High Availability (HA), Load Balancing, CI/CD pipelines, automation, backups, and scalable FreeSWITCH deployments.
• Preferred (Experience 2) – Experience implementing WebRTC-based calling solutions, including mod_verto, SIP over WSS, DTLS-SRTP, ICE, and OPUS codec configuration.

Experience: 4–10 years · Work from office · 5 days a week · Notice period up to 30 days