Senior Infrastructure Engineer

Stack

Responsibilities

• ▹Administer, monitor and maintain customer-facing cloud infrastructure (Azure and/or AWS, OVH Cloud)
• ▹Own SIP telephony integrations for customer deployments: configure and maintain connectivity via SIP trunking providers, direct trunks and customers' enterprise telephony infrastructure (PBX, SBC, CCaaS)
• ▹Design reliable call paths balancing latency, audio quality, reliability and security
• ▹Diagnose and resolve complex telephony and connectivity issues, including call routing, NAT traversal, codec compatibility, RTP/audio quality, firewall and QoS configuration
• ▹Ensure high availability, low latency and resilience of real-time voice and conversational AI services
• ▹Support customer onboarding and go-lives with Delivery and Professional Services, from proof-of-concept through production
• ▹Manage containerized workloads and orchestration platforms (Docker, Kubernetes)
• ▹Lead incident response and root cause analysis for infrastructure, telephony and connectivity issues
• ▹Perform routine system administration: patching, backups, disaster recovery testing, user and access management, capacity planning
• ▹Harden systems and enforce security best practices, supporting compliance requirements (e.g. ISO 27001, GDPR, SOC 2) and audits
• ▹Manage databases, networking, DNS, load balancing, certificates, and VPN/firewall configurations
• ▹Work with Engineering to turn recurring customer integration challenges into platform and process improvements
• ▹Create and maintain technical documentation, runbooks and integration guides

Requirements

• ▹5+ years of experience in system administration, DevOps, VoIP/telephony engineering or related infrastructure roles
• ▹Hands-on experience with SIP-based integrations, SIP trunking, call routing concepts and real-world troubleshooting across networks and enterprise environments
• ▹Strong Linux administration skills (Ubuntu/Debian/CentOS), including shell scripting (Bash) and scripting in Python or similar
• ▹Hands-on experience with public cloud platforms (Azure and/or AWS): compute, networking, storage and identity services
• ▹Practical experience with containerization (Docker) and orchestration (Kubernetes)
• ▹Experience with monitoring, logging and alerting tools and a structured approach to incident management
• ▹Solid understanding of networking fundamentals (TCP/IP, DNS, VPN, firewalls, load balancing, NAT) and security best practices
• ▹Strong troubleshooting and problem-solving skills with a proactive, ownership-driven mindset
• ▹Strong organizational skills, managing multiple priorities independently in a fast-paced, customer-facing environment
• ▹Professional proficiency in Czech and English

Nice to have

• ▹Deep experience operating real-time communication infrastructure (VoIP, SIP, WebRTC, telephony platforms, session border controllers) or other latency-sensitive services
• ▹Experience with SIP/VoIP diagnostic and analysis tools (e.g. Wireshark, sngrep, SIP tracing)
• ▹Experience supporting conversational AI, contact center, CCaaS or speech technology platforms (e.g. Genesys, Avaya, Cisco, Twilio, Vonage)
• ▹Exposure to database administration (PostgreSQL, MySQL, MongoDB, Redis) and message queues (RabbitMQ, Kafka)
• ▹Familiarity with security and compliance frameworks (ISO 27001, SOC 2, GDPR) in a SaaS environment
• ▹Relevant certifications such as Azure Administrator Associate, AWS SysOps Administrator, CKA or Linux (LPIC/RHCSA)
• ▹Experience in a high-growth startup or scale-up, ideally within a multinational organization

Soft skills

What we offer

• ▹Maternity and paternity leave, ample holidays
• ▹Fitness and health reimbursement
• ▹Tuition reimbursement
• ▹Perks supporting work-life balance

About the company

CallMiner is a global leader in AI-powered conversation intelligence and customer experience automation. Its platform analyzes all omnichannel customer interactions to help organizations improve CX, enhance agent performance and automate at scale, serving leading brands in technology, media and telecom, retail, manufacturing, financial services, healthcare and travel.