VoIP/DevOps Engineer (SIP Focus)

About Squaretalk

Squaretalk is a global cloud communications platform helping businesses connect with their customers through flexible, scalable, and secure technology. Behind our intuitive SaaS products lies a complex, high-availability VoIP infrastructure that enables reliable, real-time communication across continents.

We’re looking for an engineer who lives and breathes SIP and VoIP, and who also has solid DevOps fundamentals to keep that infrastructure running 24/7. If you’re equally comfortable tracing a one-way-audio issue across a SIP trunk and hardening a Linux production server, we want to talk to you.

Role Summary

As a VoIP / DevOps Engineer, you’ll own the health, performance, and reliability of our voice infrastructure — Asterisk, FreePBX, FreeSWITCH, and Kamailio — running on Linux in the cloud. You’ll diagnose call-quality and signaling issues, scale our telephony platform, and keep the systems behind it stable and secure.

You’ll collaborate closely with engineering, QA, and support teams to deploy changes, monitor system and call health, and proactively prevent outages. This role is a strong fit for someone with deep VoIP/SIP expertise who enjoys the operational, automation, and infrastructure side of keeping a real-time platform online.

Key Responsibilities

• Operate, troubleshoot, and optimize our VoIP/SIP stack: Asterisk, FreePBX, FreeSWITCH, and Kamailio
• Partner with the Carrier team on complex SIP and call-quality investigations — stepping in when an issue points to FreeSWITCH or the underlying servers/infrastructure
• Monitor systems, services, networks, and live call health; respond to alerts and resolve incidents promptly
• Maintain, troubleshoot, and optimize Linux-based production servers
• Manage and scale cloud services on AWS and DigitalOcean
• Configure, deploy, and manage containerized applications using Docker
• Automate routine operational tasks and infrastructure provisioning
• Maintain and optimize MySQL and Redis databases; manage backup and recovery procedures
• Collaborate with developers on application deployments and CI/CD pipelines
• Ensure system security hardening and timely updates
• Document configurations, procedures, and incident responses

Required Skills and Experience

• Hands-on experience with VoIP/SIP systems — specifically Asterisk, FreePBX, and FreeSWITCH — in production
• Strong understanding of SIP signaling, call routing, and VoIP troubleshooting (SIP tracing, log analysis, QoS concepts)
• 3+ years in a DevOps, SysAdmin, or NOC role
• Strong Linux system administration skills
• Solid networking knowledge (TCP/IP, DNS, firewalls, routing, network troubleshooting) — with an emphasis on how it applies to real-time voice traffic
• Hands-on experience with AWS and/or DigitalOcean
• Strong experience with Docker in production environments
• Experience with MySQL, Redis, and backup strategies
• Familiarity with monitoring tools such as Zabbix
• Good understanding of PHP-based applications and basic debugging
• Experience with Bash and/or PHP scripting
• Working knowledge of CI/CD pipelines (Jenkins, GitLab CI, or similar)

Nice to Have

• Experience with Kamailio (a plus — we’re expanding our use of it)
• Performance tuning for high-traffic, real-time environments
• Experience with Nginx and/or Apache web servers
• Familiarity with security hardening and compliance basics
• Comfortable with Agile/Scrum environments
• Terraform / infrastructure-as-code experience
• Kubernetes knowledge

What You’ll Get

• Work in a modern infrastructure environment that powers real-time communication at scale
• Join a fast-paced, international team with a strong engineering culture
• Be part of a mission-critical team behind a platform used by companies worldwide
• Opportunities to learn and grow in cloud, security, and automation fields
• Competitive salary and hybrid work flexibility in our Sofia / Jerusalem office