Senior Infrastructure Engineer (SIP Telephony & Cloud)

About the role

CallMiner is looking for a Senior Infrastructure Engineer (DevOps System Administrator) to join its Engineering and Operations Team in Prague. The role owns the reliability, security and performance of the infrastructure behind CallMiner's intelligent CX automation platform, including OmniAgent, which connects AI virtual agents to customers' contact centers and telephony environments. It focuses on customer-facing infrastructure and SIP telephony integration, from the moment a customer's phone rings until the AI agent answers.

Key responsibilities

• Administer, monitor and maintain customer-facing cloud infrastructure (Azure and/or AWS, OVH Cloud).
• Own SIP telephony integrations: configure and maintain connectivity via SIP trunking providers, direct trunks and customers' PBX, SBC and CCaaS infrastructure.
• Design reliable call paths balancing latency, audio quality, reliability and security.
• Diagnose and resolve telephony and connectivity issues such as call routing, NAT traversal, codec compatibility, RTP/audio quality, firewall and QoS.
• Support customer onboarding and go-lives with Delivery and Professional Services, from proof-of-concept to production.
• Manage containerized workloads (Docker, Kubernetes) and lead incident response and root cause analysis.
• Handle patching, backups, disaster recovery testing, user and access management, and capacity planning.
• Harden systems and support compliance (ISO 27001, GDPR, SOC 2) and audits.
• Maintain technical documentation, runbooks and integration guides.

Required profile

• 5+ years in System Administration, DevOps, VoIP/telephony engineering or related infrastructure roles.
• Bachelor's degree preferred in Computer Science, Information Technology or a related discipline, or equivalent practical experience.
• Strong Linux administration (Ubuntu/Debian/CentOS) with Bash scripting and Python or similar.
• Public cloud (Azure and/or AWS) and containerization (Docker, Kubernetes) experience.
• Proficiency in Czech and English required.

Required skills

• SIP trunking, call routing, NAT traversal, TCP/IP, DNS, VPN, firewalls and load balancing.
• Monitoring, logging and alerting tools; incident management.
• Preferred: VoIP/SIP/WebRTC, Wireshark, SIP tracing, database administration (PostgreSQL, MySQL, MongoDB, Redis) and message queues (RabbitMQ, Kafka).

What we offer

• Maternity and paternity leave and ample holidays.
• Fitness and health reimbursement, tuition reimbursement and more.