Telephony Engineer (FreeSWITCH, VoIP )

Hiring for a Client - eDAS

This position centers on deploying, establishing, customizing, connecting, and supporting FreeSWITCH-based VoIP platforms. You will partner with teams managing SIP, RTP, WebRTC, IVR, conferencing, call routing, and third-party integrations in live operational settings.

FreeSWITCH Core Responsibilities

• Set up, establish configuration of, and operate FreeSWITCH within production settings from initial implementation
• Build and execute call flows, dialplans, IVRs, conferencing, and call routing with full accountability
• Set up SIP profiles (internal/external), gateways, trunks, and extensions
• Build multi-tenant and high-availability FreeSWITCH setups

SIP, RTP & Networking

• Demonstrate deep comprehension of SIP signaling, RTP media, and SDP negotiation
• Resolve one-way audio, audio loss, dropped calls, and registration problems
• Establish NAT traversal, firewall settings, and RTP port configurations
• Review SIP logs and packet captures (siptrace, sngrep, tcpdump)

Dialplan & Scripting

• Develop dialplans with XML and Lua / JavaScript / Python
• Create implementations for call queues for inbound and outbound calls, time-based routing, skill-based routing, and failover and fallback handling

Integrations & APIs

• Connect FreeSWITCH to CRM / ERP systems, billing platforms, AI voice bots (ASR/TTS), and external WebSocket or REST services
• Leverage Event Socket Library (ESL) for inbound & outbound ESL, real-time call control and monitoring

WebRTC & Media

• Set up WebRTC support (DTLS-SRTP, ICE, OPUS)
• Engage with mod_verto, SIP over WSS
• Roll out browser-based calling systems

Monitoring & Debugging

• Track system performance and call quality
• Examine logs and CDRs
• Enhance codec usage and RTP performance
• Address live production incidents and RCA

Deployment & Operations

• Establish FreeSWITCH on Linux (CentOS / Ubuntu) and cloud platforms (AWS / GCP / Azure – preferred)
• Organize HA, load balancing, and scaling
• Partner with DevOps teams for CI/CD, backups, and automation

Requirements

• Expert-level FreeSWITCH Implementation Engineer background
• Mandatory (Experience 1) – Minimum 4 years of professional experience, including at least 3 years of direct hands-on expertise implementing, configuring, and supporting FreeSWITCH in production environments
• Mandatory (Experience 2) – Proven capability in architecting and executing FreeSWITCH call flows, dialplans, IVRs, call routing, conferencing, SIP profiles, gateways, trunks, and extensions with end-to-end ownership
• Mandatory (Experience 3) – Extensive practical expertise with VoIP technologies, including SIP, RTP, RTCP, SDP, WebRTC, along with problem-solving skills for call drops, one-way audio, registration failures, NAT traversal, and SIP/RTP-related issues
• Mandatory (Experience 4) – Hands-on involvement in building FreeSWITCH dialplans via XML and proficiency in at least one scripting language such as Lua, JavaScript, or Python, with implementations of call queues, time-based routing, skill-based routing, and failover logic
• Mandatory (Experience 5) – Experience connecting FreeSWITCH with CRM/ERP systems, REST APIs, WebSockets, AI Voice Bots (ASR/TTS), or Billing Platforms, with direct experience using Event Socket Library (ESL) for real-time call control
• Mandatory (Experience 6) – Deep Linux administration capabilities and readiness to provision and oversee FreeSWITCH on Ubuntu/CentOS, combined with troubleshooting via fs_cli, sngrep, tcpdump, and SQL (MySQL/PostgreSQL) experience for CDRs and reporting
• Mandatory (Notice Period) – Those available to begin immediately or who can commence within 15 days are especially sought
• Preferred (Experience 1) – Background with AWS, Azure, or GCP, High Availability (HA), Load Balancing, CI/CD pipelines, automation, backups, and scalable FreeSWITCH deployments
• Preferred (Experience 2) – Experience building WebRTC-based calling applications, covering 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