Telephony Engineer (FreeSWITCH, VoIP )

Roles & Responsibilities

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

Ideal Candidate

1Strong FreeSWITCH Implementation Engineer Profiles

2Mandatory (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.

3Mandatory (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.

4Mandatory (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.

5Mandatory (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.

6Mandatory (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.

7Mandatory (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.

8Preferred (Experience 1) – Experience with AWS, Azure, or GCP, High Availability (HA), Load Balancing, CI/CD pipelines, automation, backups, and scalable FreeSWITCH deployments.

9Preferred (Experience 2) – Experience implementing WebRTC-based calling solutions, including mod_verto, SIP over WSS, DTLS-SRTP, ICE, and OPUS codec configuration.