VoIP and AI Communications Developer

Position Overview 

• Design, build, integrate, and support carrier-grade VoIP platforms, AI voice agents, and virtual receptionist solutions. 

• Work hands-on with Asterisk, FreeSWITCH, Kamailio, OpenSIPS, NetSapiens, Bandwidth, and Twilio. 

• Strong Python development skills are required; React experience is an asset. 

Key Responsibilities 

• Design, develop, deploy, and maintain scalable VoIP applications and services. 

• Build backend services, REST APIs, integrations, and automation tools using Python. 

• Develop AI voice agents and virtual receptionist solutions that answer calls, route callers, schedule appointments, respond to questions, and handle common customer requests. 

• Integrate speech-to-text, text-to-speech, natural-language processing, and large language models with real-time VoIP systems. 

• Connect AI agents with SIP trunks, PBX platforms, CRM systems, calendars, contact centers, and business applications, including reliable escalation and transfer to human representatives. 

• Configure Asterisk and FreeSWITCH dial plans, IVRs, queues, voicemail, conferencing, recording, and complex call flows. 

• Develop and maintain Kamailio and OpenSIPS configurations for SIP proxying, registration, authentication, routing, load balancing, failover, and security. 

• Administer, customize, and integrate NetSapiens domains, users, devices, call-routing rules, provisioning workflows, and APIs. 

• Integrate and manage Bandwidth and Twilio services for SIP trunking, programmable voice, messaging, telephone numbers, call routing, and emergency calling. 

• Develop applications using Bandwidth and Twilio APIs, SDKs, webhooks, and programmable communications services. 

• Integrate SIP carriers, session border controllers, gateways, PBX platforms, and third-party communications services. 

• Build provisioning, billing, reporting, monitoring, messaging, and telephone-number management integrations. 

• Build or enhance web-based administration, monitoring, and reporting interfaces; React experience is an asset. 

• Troubleshoot signaling, audio, registration, NAT, codec, latency, jitter, packet loss, webhook, and carrier-interoperability issues. 

• Analyze SIP and RTP traffic using sngrep, Wireshark, Homer, logs, metrics, and packet captures. 

• Improve availability, voice quality, scalability, security, and disaster-recovery capabilities. 

• Protect systems against toll fraud, SIP scanning, denial-of-service attacks, prompt injection, unauthorized access, and improper handling of customer data. 

• Create technical documentation, deployment procedures, diagrams, and operational runbooks; participate in testing, releases, incident response, and on-call support. 

Required Qualifications 

• Professional experience developing or supporting production VoIP platforms. 

• Hands-on knowledge of Asterisk, FreeSWITCH, Kamailio, OpenSIPS, and NetSapiens. 

• Experience integrating Bandwidth and Twilio APIs, SIP trunks, webhooks, telephone-number services, and programmable communications. 

• Strong Python development experience, including backend services, APIs, integrations, testing, and automation. 

• Strong understanding of SIP, SDP, RTP, RTCP, DTMF, codecs, and call-state management. 

• Experience developing dial plans and complex inbound and outbound call-routing logic. 

• Knowledge of SIP registration, authentication, trunks, number normalization, least-cost routing, and failover. 

• Understanding of AI voice-agent architecture, including speech recognition, speech synthesis, language models, conversation state, and tool calling. 

• Experience integrating APIs, webhooks, databases, and third-party business systems. 

• Strong understanding of TCP/IP, UDP, DNS, NAT, TLS, WebSockets, firewalls, and load balancing. 

• Familiarity with MySQL, MariaDB, PostgreSQL, or comparable relational databases. 

• Linux administration, Git, automated testing, CI/CD, and command-line troubleshooting experience. 

• Ability to diagnose complex VoIP and AI call-flow issues using logs, traces, metrics, and packet captures. 

• Strong analytical, documentation, collaboration, and communication skills. 

Preferred Qualifications 

• Experience building AI voice agents, virtual receptionists, conversational IVRs, or contact-center automation. 

• Experience with React and modern JavaScript or TypeScript. 

• Familiarity with real-time AI APIs, retrieval-augmented generation, function calling, guardrails, and conversation evaluation. 

• Advanced experience with Bandwidth or Twilio voice, messaging, number provisioning, emergency services, and carrier integrations. 

• Experience with WebRTC, SIP over WebSocket, STUN, TURN, and ICE. 

• Familiarity with SBCs, RTPengine, RTProxy, media servers, and SIPp. 

• Experience integrating CRM, scheduling, ticketing, payment, or contact-center platforms. 

• Experience with E911, CNAM, LNP, SMS/MMS, fax, call recording, and carrier services. 

• Knowledge of telecom fraud prevention, robocall mitigation, STIR/SHAKEN, consent requirements, and privacy regulations. 

• Experience with Docker, Kubernetes, AWS, Azure, or another cloud platform. 

• Familiarity with high-availability architectures, replication, clustering, geographic redundancy, and high-volume multi-tenant hosted PBX environments. 

• Knowledge of Homer, Prometheus, Grafana, ELK/OpenSearch, or comparable observability tools. 

Good to Have 

• Hands-on experience with WebRTC for real-time audio/video communication in web applications.  

• Familiarity with SIP-based communication and JavaScript SIP libraries such as SIP.js or JsSIP.  

• Understanding of browser-based WebRTC APIs, including media streams, peer connections, and real-time communication concepts.  

Success in This Role 

• Success will be measured by platform reliability, voice quality, accurate call routing, dependable Bandwidth and Twilio integrations, AI-agent performance, safe and effective customer interactions, rapid incident resolution, maintainable Python code, effective automation, and delivery of scalable VoIP and virtual receptionist services.