Freeswitch Developer at Monjura Parveen · Kolkata · 4 - 8 years · ₹5L - ₹12L / yr · Posted 4 Sep 2025

Job Opening: FreeSWITCH Developer
Location: Ecospace Business Park, Rajarhat, Newtown, Kolkata
Employment Type: Full-Time, Permanent
Shift: Day Shift
Experience: Minimum 4+ years in FreeSWITCH/VoIP Development
Responsibilities:
- Design, develop, deploy, troubleshoot, and maintain tools and services supporting our cloud telephony network.
- Customize FreeSWITCH for large-scale audio/video conferencing (1000–1500 concurrent calls).
- Expertise in SIP, RTP, RTCP, TURN, STUN, NAT, TLS.
- Hands-on experience with RTP Proxy and routed audio conferences.
- Understanding of SDP Protocol offer/answer mechanism.
- Work with load testing tools for FreeSWITCH audio conferences.
- Deploy and manage multiple FreeSWITCH instances using load balancers.
- Debug issues using packet captures (Wireshark/Ngrep).
- Collaborate with mobile/API teams for integration and support.
- Knowledge of codecs (PCMU, PCMA, G729, Opus) and open-source telephony technologies (FreeSWITCH, WebRTC).
- Familiarity with SIP servers (SER/OpenSER), proxy servers, SBC, SIPX is a plus.
Qualifications:
- Bachelor’s degree in Engineering (B.Tech/MCA).
- 4+ years of hands-on experience in FreeSWITCH development or related VoIP technologies.
- Strong knowledge of Linux environments and command-line tools.
- Basic to intermediate SQL knowledge.
- Proficiency in scripting (Bash, Python, Perl) for automation.
- Strong understanding of VoIP protocols (SIP, RTP), networking principles (TCP/IP, DNS, DHCP, routing protocols).
- Excellent troubleshooting skills with ability to resolve complex technical issues.
- Strong problem-solving, communication, and collaboration skills.
Industry Preference:
- Travel (Preferred)
- Any Industry (Required)

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WE ARE HIRING | PROJECT MANAGER – VOIP TECHNOLOGIES
Position: Project Manager
Industry: IT Services / VoIP Technologies
Experience: 6–12 Years
Location: Ahmedabad | Work from Office
We are looking for a Technical Project Manager with a strong hands-on technical background in VoIP Development
.
KEY RESPONSIBILITIES
• Manage end-to-end VoIP implementation projects from initiation through deployment and post-implementation support.
• Gather business and technical requirements and translate them into actionable project plans.
• Prepare project schedules, milestones and resource allocation plans.
• Coordinate with Development, QA, DevOps, Support and Infrastructure teams.
• Track project progress and ensure timely delivery.
• Conduct project kickoffs, status meetings and client review meetings.
• Identify project risks and develop mitigation strategies.
• Manage scope changes and maintain project documentation, reports and dashboards.
• Coordinate UAT and production rollout.
• Manage timelines, budgets and resource utilisation.
• Communicate project status to clients and internal stakeholders.
• Support pre-sales through effort estimation and project planning.
MANDATORY TECHNICAL EXPERIENCE
Hands-on experience in VoIP/Telecom with strong knowledge of:
• FreeSWITCH
• Asterisk
• Kamailio
• OpenSIPS
• SIP
• RTP
• WebRTC
• SBC
• IP Telephony
• Linux
• TCP/IP, NAT, Firewalls and Networking
ADDITIONAL SKILLS
• Agile / Scrum methodologies
• Project planning and scheduling
• Risk and resource management
• Client and stakeholder management
• UAT and production deployment
• Vendor coordination
• International client handling
• AWS / Azure / GCP exposure is an advantage
• REST API integration knowledge is an advantage
• PMP / PRINCE2 / CSM certification preferred
We’re building a powerful, AI-driven communication platform — a next-generation alternative to RingCentral or 8x8 — powered by OpenAI, LangChain, and SIP/WebRTC. We're looking for a Full-Stack Software Developer who’s passionate about building real-time, AI-enabled voice infrastructure and who’s excited to work in a fast-moving, founder-led environment.
This is an opportunity to build from scratch, take ownership of core systems, and innovate on the edge of VoIP + AI.
What You’ll Do
- Design and build AI-driven voice and messaging features (e.g. smart IVRs, call transcription, virtual agents)
- Develop backend services using Python, Node.js, or Golang
- Integrate OpenAI, Whisper, and LangChain with real-time VoIP systems like Twilio, SIP, or WebRTC
- Create scalable APIs, handle call logic, and build AI pipelines
- Collaborate with the founder and early team on product strategy and infrastructure
- Participate in occasional in-person strategy meetings (Delhi, Bangalore, or nearby)
Must-Have Skills
- Strong programming experience in Python, Node.js, or Go
- Hands-on experience with VoIP/SIP, WebRTC, or tools like Twilio, Asterisk, Plivo
- Experience integrating with LLM APIs, OpenAI, or speech-to-text models
- Solid understanding of backend design, Docker, Redis, PostgreSQL
- Ability to work independently and deliver production-grade code
Nice to Have
- Familiarity with LangChain or agent-based AI systems
- Knowledge of call routing logic, STUN/TURN, or media servers (e.g. FreeSWITCH)
- Interest in building scalable cloud-first SaaS products
Work Setup
- 🏠 Remote work
- 🕐 Full-time role
- 💼 Direct collaboration with founder (technical)
- 🧘♂️ Flexible hours, strong ownership culture






