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

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