Senior Software Engineer - FreeSWITCH / VoIP

About the role

We're looking for an experienced FreeSWITCH Developer / VoIP Software Engineer to design, develop, and maintain the telephony solutions that power Vonage's call processing platform. You'll build real-time voice communication systems that handle millions of calls, developing features like call processing, recording, voicemail, conferencing, and external service integrations. This is a critical role where your work directly impacts business communications for customers worldwide. Vonage is a global cloud communications leader. And your talent will further help brands - such as Airbnb, Viber, WhatsApp, and Snapchat - accelerate their digital transformation through our fully programmable-based unified communications, contact center solutions, and communications APIs. Ready to innovate? Then join us today. Note: The purpose of this profile is to provide a

Responsibilities

• Core Responsibilities
• Build scalable telephony systems - Design and develop distributed, high-volume production telephony applications for our UCaaS platform that handle real-time voice traffic at scale
• Develop custom FreeSWITCH solutions - Create custom modules, dialplan configurations, and ESL (Event Socket Library) integrations for advanced call control and automation
• Deliver advanced telephony features - Implement call recording, voicemail transcription, fax processing, audio streaming, and other mission-critical voice features
• Rapid prototyping to production - Build proof-of-concepts quickly and evolve them into production-ready, maintainable code
• Drive technical innovation - Evaluate emerging telephony technologies and recommend architectural improvements that enhance our platform capabilities
• Mentor and lead - Guide team members on design patterns, best practices, and telephony architecture decisions
• Day-to-Day Collaboration
• Participate in the full agile development lifecycle: sprint planning, design reviews, standups, and demos
• Respond promptly to production incidents affecting customers and business operations
• Work independently on end-to-end feature delivery while contributing to broader team goals
• Partner closely with Product Management, QA, and Operations teams to deliver cohesive solutions
• Communicate progress, blockers, and technical decisions clearly with engineering leadership

Requirements

• Required Experience & Skills
• Telephony & VoIP Expertise (Must-Have)
• 8+ years of software development experience
• 5+ years hands-on experience with telephony platforms: FreeSWITCH , Asterisk, or similar open-source PBX systems
• Deep understanding of:
• SIP (Session Initiation Protocol) and RTP protocols
• VoIP architecture and NAT traversal techniques (STUN, ICE, TURN)
• Audio codecs (G.711, Opus, etc.)
• Dialplan development and call flow design
• Programming & Development
• Strong proficiency in Java, C/C++ , Python , and SQL
• Experience with CI/CD pipelines and modern development workflows
• Infrastructure as Code practices
• Containerization with Docker and Kubernetes
• Cloud & Infrastructure
• Hands-on experience with AWS services : EC2, EKS, Lambda, S3, SNS, SQS, CloudFront
• Linux systems expertise : performance tuning, networking, file systems
• Database experience with:
• Relational : MySQL, PostgreSQL
• NoSQL : Redis, MongoDB
• Problem-Solving & Debugging
• Proven troubleshooting skills in complex, distributed production environments
• Systematic debugging approach for real-time communication systems
• Experience analyzing performance bottlenecks and system failures
• Experience with WebRTC
• Familiarity with Kamailio, OpenSIPS, or other SIP proxies
• Knowledge of PSTN interconnection and carrier integrations
• Previous UCaaS or CPaaS platform experience
• Contributions to open-source telephony projects
• Experience with monitoring and observability tools (Prometheus, Grafana, Datadog)
• Why This Role Matters
• Work Style
• Ownership mindset - Take features from concept to production
• Collaborative approach - Work across teams while driving your work independently
• Customer focus - Balance feature velocity with reliability and user experience
• Continuous improvement - Stay current with telephony trends and share knowledge with the team
• #LI-CK1
• There's no perfect candidate. You don't need all the preferred qualifications to make a valuable impact on our team. Our employees and customers come from diverse backgrounds, so if you're passionate about what you could achieve at Vonage, we'd love to hear from you.
• To learn how we process your personal data during the recruitment process, please refer to our Privacy Notice .

Additional Information

Join Vonage and help us innovate cloud communications for businesses worldwide!

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