Senior backend engineer

Role: Senior backend engineer Job Ref Id: JD-1262 Competence level: 5+ years Start date: 2026-11-02 End date: 2027-04-30 Extension option: Yes Scope: 100% Location: Stockholm Remote work: On-site Language: English Application deadline: 2026-10-25 Number of consultants: 1 Security clearance: No About The Assignment We are looking for an experienced backend engineer with expertise in Node.js and MongoDB to work on one of our core products. Responsibilities

• Develop and maintain Node.js applications
• Deploy and release new capabilities, features and fixes
• Ensure quality standards, including test automation, manage tech debt, etc.
• Collaborate with product managers to define the product roadmap
• Write and maintain tech documents, including RFCs, ADRs, postmortems, etc.
• Own tech roadmap and priorities aligning with product priorities
• Ensure observability and monitoring match industry standards
• Proactively address security issues in collaboration with our security department
• Join and actively contribute to team ceremonies
• Propose improvements in our SDLC
• Proactively identify cost saving opportunities

Requirements Mandatory

• Solid experience with TypeScript/JavaScript/Node.js and MongoDB (Mongoose ODM)
• Experience with real-time/streaming systems design (e.g. WebSockets, low-latency audio pipelines, etc.)
• Hands-on experience with Redis / ioredis (caching, rate limiting, pub/sub)
• Experience with event-driven applications and messaging systems
• Solid experience with microservices architecture and async programming
• Experience with observability/metrics tooling (e.g. Prometheus, structured logging)

Nice-to-have

• Experience with BullMQ and Node's Cluster module, working with workers and subprocesses
• Experience with LLMs and audio processing (STT/TTS)
• Experience with Keystone and Express.js
• Experience with gRPC and Protocol Buffers
• Experience with NATS (messaging queue)
• Experience with Docker and Docker Compose
• Experience with Kubernetes + ArgoCD + Kustomize (multi-region GKE deployments)
• Experience with Go and WebSocket bridging services
• Experience with cloud/VoIP telephony and telecom generally
• Experience with Kamailio / Homer
• Experience with Asterisk PBX / ARI (Asterisk REST Interface) and SIP/IAX protocols
• Experience with Firebase Admin / APNs