VoIP and AI Communications Developer

About Contour

Contour Software has grown from a dozen people to over 2,000 staff across 3 cities, in less than 14 years.

As a subsidiary of Constellation Software Inc., we are proud to be part of a global enterprise software conglomerate that has grown to become one of the top 10 software companies in the world, with employees and customers in 100+ countries. With a broad-based and ever-growing portfolio of market-leading, vertical-market enterprise solutions covering more than 100 industry domains in predominantly mature markets, CSI's recipe creates the perfect environment for professionals to build fulfilling, long-term careers.

What started as an R&D & Accounting back-office, has progressed into a full-service Global Centre serving all functions and departments, at the divisional as well as operating group/corporate level. Today Contour employees, located in Karachi, Lahore & Islamabad, are serving CSI divisions located in time zones spanning the globe, from Sydney to Vancouver. With the global growth of Constellation as the wind in our sails, we are only just getting started!

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 maintainscalable 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 FreeSWITCHdial plans, IVRs, queues, voicemail, conferencing, recording, and complex call flows.

• Develop and maintain Kamailioand OpenSIPSconfigurations for SIP proxying, registration, authentication, routing, load balancing, failover, and security.

• Administer, customize, and integrate NetSapiensdomains, 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-recoverycapabilities.

• 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; participatein testing, releases, incident response, and on-call support.

Required Qualifications

• Professional experience developing or supporting productionVoIP 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 ofAI 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, accuratecall 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.

Exciting Benefits we offer:

• Market-leading Salary
• Medical Coverage - Self & Dependents
• Parents Medical Coverage
• Provident Fund
• Employee Performance-based bonuses
• Home Internet Subsidy
• Conveyance Allowance
• Profit Sharing Plan [Tenured Employees Only]
• Life Benefit
• Child Care Facility
• Company Provided Lunch/Dinner
• Professional Development Budget
• Recreational area for in-house games
• Sporadic On-shore training opportunities
• Friendly work environment
• Leave Encashment

Disclaimer: At Contour, we attribute our success to the unique contributions of our diverse staff. We’re committed to fostering a culture of respect that thrives on the varied perspectives and experiences of all individuals we recruit, employ, promote, and compensate. Since day one, we’ve adhered to a policy that champions a work environment honoring the worth and dignity of each person while being free from all forms of employment discrimination.

In our continuous effort to promote inclusivity, we extend our commitment to individuals with special needs by providing reasonable accommodations. We actively encourage qualified individuals with special needs to apply for the various openings within our company. Should you require assistance in completing the application process or have any inquiries regarding special facilities, please do not hesitate to contact our HR team. Your unique talents and abilities are welcomed and valued here.