Senior Node.js developer

6+ years of experience

Plovdiv, Sofia

Hybrid

Our client is a full-service telecommunications provider that develops and delivers multimedia and internet services for residential customers. It supplies services to independent cable network operators and utility companies via a fiber-optic backbone and also operates directly as an internet and TV service provider in selected regions.
committed, or shared. No AI output goes directly into production code, documentation, or client-facing materials without review by the engineer responsible for it.

ROLE SUMMARY

You build and own the server-side microservices of our client's new BSS platform. This includes the Eligibility and Cost-Optimization Engine, the Swiss QR-invoice microservice, the event-driven notification service, and the integration with the retained QMC .NET monolith. You work primarily in Node.js / TypeScript and define the API contracts consumed by the Frontend Engineer.

RESPONSIBILITIES

Design and build the Eligibility and Cost-Optimization Engine - queries QMC Available Services API, applies cost-priority matrix logic, returns cheapest available product at a given address.
Build the Swiss QR-invoice microservice: consumes Lago invoice.created webhooks, generates QR-invoice PDFs per SIX Group specification using Gotenberg.
Implement the event-driven notification service (email and SMS) across order, billing, and payment lifecycle events.
Own the integration with the QMC Provisioning API - triggering technical product activation from order events with error handling and observability.
Define REST API contracts with the Frontend Engineer from Sprint 0. Maintain API documentation throughout.
Instrument all services with OpenTelemetry for end-to-end distributed tracing to DataDog.
Enforce 90% unit test coverage on all new code.

REQUIRED SKILLS

Node.js / TypeScript: 6+ years building production microservices. Strong async patterns, event-driven architecture.
REST API and webhook design: Experienced designing and documenting contracts consumed by frontend and third-party systems.
Event-driven integration: Message bus experience (Kafka, RabbitMQ, or NATS). Webhook producer/consumer patterns.
PostgreSQL: Production experience. Query optimization, schema design, migrations.
Docker / Kubernetes: Confident containerizing services and writing Kubernetes manifests or Helm values.
OpenTelemetry: Hands-on instrumentation of Node.js services for distributed tracing.
Testing: Jest or equivalent. Integration testing across service boundaries, contract testing awareness.