Backend systems that are secure, documented, and built to scale
Most API problems surface six months after launch — when the authentication system cannot handle SSO, the rate limiter does not exist, the docs are outdated, and the test coverage is zero. By then, fixing it requires a rewrite more disruptive than building it properly in the first place.
We design and build Node.js APIs with the end state in mind. Clean architecture, TypeScript throughout, every security control in place before the first endpoint ships, OpenAPI docs generated from code, and a test suite that covers the critical paths. Whether you need a single integration API or a full microservices backend, we deliver it production-ready — not production-adjacent.
What We Build
Four core areas of Node.js backend development — each with depth, not just breadth.
REST APIs
Resource-oriented APIs designed to be used, not just shipped
We design REST APIs that are intuitive to integrate with — consistent resource naming, predictable error formats, versioning from day one, and complete OpenAPI 3.1 documentation. Every endpoint is tested, rate-limited, and built to handle real-world edge cases.
What's included
- OpenAPI 3.1 spec and Swagger UI documentation
- Consistent error format with error codes and messages
- Cursor and offset-based pagination
- API versioning strategy (v1, v2) built in from the start
- Postman collection and integration test suite
- Rate limiting, request validation, and CORS handling
Authentication & Authorisation
Production-hardened auth that covers every case
Authentication is where APIs most commonly go wrong — insecure tokens, missing refresh flows, no revocation, incomplete RBAC. We build auth systems that cover every case: short-lived JWTs, refresh token rotation, SSO, multi-tenant isolation, and fine-grained permission models.
What's included
- JWT access tokens with short expiry and refresh rotation
- OAuth 2.0 — authorization code, client credentials, PKCE flows
- SAML 2.0 and OpenID Connect for enterprise SSO
- API key management with scopes and per-key rate limits
- Role-based access control (RBAC) and attribute-based (ABAC)
- Multi-tenant data isolation at the query level
Third-Party Integrations
Connect your system to every platform your business depends on
APIs rarely live in isolation. We build the integration layer that connects your backend to payment processors, CRMs, communication platforms, and data providers — with proper webhook handling, retry logic, and error recovery so integrations stay reliable under real conditions.
What's included
- Payment gateways — Stripe, GoCardless, PayPal
- CRM platforms — HubSpot, Salesforce, Pipedrive
- Communication — SendGrid, Mailgun, Twilio, Slack
- Webhook ingestion with signature verification and retry queues
- OAuth 2.0 integrations to any third-party platform
- Data sync pipelines with conflict resolution
Microservices Architecture
Distributed systems built to scale independently
When a monolith starts to crack under load or team size, a well-designed microservices architecture solves real problems. We design service boundaries around business domains, implement async communication via message queues, and add the observability layer that makes distributed systems debuggable.
What's included
- Domain-driven service decomposition
- Async messaging with RabbitMQ, Kafka, or AWS SQS/SNS
- Service-to-service authentication with mutual TLS or API tokens
- Distributed tracing with OpenTelemetry
- Circuit breakers and graceful degradation
- Shared API gateway with routing, auth, and rate limiting
Our Engineering Standards
These practices are not optional on our projects — every API we ship meets this bar.
OpenAPI docs as standard
Every API ships with a machine-readable OpenAPI 3.1 spec, Swagger UI, and a Postman collection. No detective work for your frontend team.
OWASP Top 10 compliance
Input validation, parameterised queries, helmet.js headers, CORS policy, and rate limiting — security built in, not bolted on.
Performance from the start
Connection pooling, query optimisation, Redis caching, and async I/O — we profile under realistic load before every release.
Migrations and seeding
Every schema change ships as a reversible migration. Dev, staging, and production databases stay in sync without manual steps.
Structured logging
JSON-structured logs with request ID correlation, timing, and error context — ready for Datadog, CloudWatch, or any log aggregator.
Error handling done right
Global error handler, consistent error schema, operational vs programmer error separation, and never-leak-stack-traces in production.
Retry and idempotency
Idempotency keys for payment and mutation endpoints, retry-safe webhook handlers, and queue-based job deduplication.
Test suite included
Unit tests for business logic, integration tests against a real test database, and contract tests for third-party integrations.
Background jobs
Cron jobs, delayed tasks, and event-driven workers via BullMQ — with job progress tracking, retries, and dead-letter queues.
Technologies We Use
Battle-tested tools chosen for reliability, ecosystem maturity, and long-term maintainability.
How an API Project Works
A structured delivery process — from API design to a production-hardened system your team can operate.
Discovery & API Design
We start by mapping every consumer of the API — web clients, mobile apps, third-party partners, internal services. We document authentication requirements, data contracts, expected throughput, and SLA expectations before writing a line of code. You get an API design document to review and sign off before development starts.
Architecture & OpenAPI Spec
We produce an OpenAPI 3.1 specification and architecture diagram covering every endpoint, request/response schema, error format, auth flow, and database design. Writing the spec first means your frontend team can start building against mock responses while we build the real API in parallel.
Environment & CI Setup
Before any feature code, we establish the project structure, environment configuration, database migration tooling, CI pipeline, and deployment scripts. Every developer gets a reproducible local environment. Staging is configured to mirror production from day one.
Sprint-Based Development
Development runs in two-week sprints. Each sprint delivers a set of working endpoints — deployed to staging, documented in Swagger, and covered by tests. You test every endpoint as it is built, giving feedback that shapes the next sprint rather than discovering problems at the end.
Security Audit & Load Testing
Before any production deployment, we run a full OWASP Top 10 security review, penetration-test the authentication and authorisation flows, and run load tests to verify the API meets its SLA under expected peak traffic. Any findings are fixed before you see the final build.
Production Deployment & Handover
We manage the production deployment — containerised via Docker, health checks, environment variables via secrets manager, monitoring and alerting, and rollback plan. You receive full source code, architecture documentation, API reference, runbook, and a handover session with your engineering team.
Node.js API Pricing Guide
Fixed-price projects with clear scopes — here is what Node.js backend development typically costs.
Integration or Feature API
£5,000 – £15,000
A focused API project — a new integration with a third-party platform, an authentication system, a background job service, or a set of new endpoints on an existing backend.
- TypeScript + Express or Fastify
- Up to 20 endpoints
- OpenAPI 3.1 documentation
- JWT or OAuth 2.0 authentication
- Integration test suite
- Docker deployment configuration
Full Backend API
£15,000 – £50,000
A complete backend system — multi-resource REST API, full auth system, third-party integrations, background job workers, and production infrastructure.
- NestJS or Express + TypeScript
- PostgreSQL + Prisma with migrations
- OAuth 2.0 / SAML SSO auth
- Background job queue (BullMQ)
- Unit + integration + E2E test suite
- CI/CD pipeline + staging environment
API Retainer
From £1,500/month
Ongoing Node.js backend development — new features, third-party integrations, security patches, performance tuning, and on-call support on a rolling monthly contract.
- Dedicated senior Node.js engineer
- Agreed monthly sprint deliverables
- Priority security patch response
- Monthly performance review
- On-call support SLA
- Cancel with 30 days notice
All prices are estimates — final costs depend on scope and integrations. View full pricing guide →
Frequently Asked Questions
Straight answers to the questions every Node.js API buyer asks.
Which Node.js framework do you recommend — Express, Fastify, or NestJS?
Do you build GraphQL APIs or just REST?
How do you handle API versioning?
What database should we use with our Node.js API?
How long does a Node.js API project take?
Can you take over an existing Node.js codebase?
Need a production-ready API?
Tell us about your integration requirements, expected traffic, authentication needs, and timeline. We will come back with a clear technical proposal — including architecture diagram, database schema approach, and a fixed-price quote — within one business day.
Free scoping call · No commitment · UK-based team