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Freelance Node.js Developer: APIs and Back-ends

Behind every serious web application there is an API. We build Node.js back-ends in TypeScript that hold up under load, expose clear contracts (OpenAPI) and integrate cleanly with your tools: payments, CRM, ERP, messaging. All of it with tests, usable logs and documentation your next developer will thank you for.

Describe my project

What we do

01

REST and GraphQL APIs

Documented contracts (OpenAPI/Swagger), input validation, versioning, pagination: an API your partners and mobile apps can consume without surprises.

02

Authentication and security

Sessions or JWT, OAuth (Google, Microsoft), roles and permissions, rate limiting, audit logs: OWASP fundamentals applied from the first route.

03

Integrations and webhooks

Stripe, HubSpot, Odoo, Slack, carriers, business APIs: reliable synchronisation with queues, retries and idempotency.

04

Data and performance

PostgreSQL modelling, versioned migrations, Redis caching, asynchronous processing: a healthy database that stays fast as volume grows.

An API built to last

A good API is one that does not surprise: consistent naming, explicit errors, strict input validation, paginated responses, a version in the URL. We apply these rules from day one, because fixing them afterwards costs ten times more. Data schemas are shared between the API and its clients, such as a React or Next.js front-end (TypeScript on both sides), which removes a whole class of bugs.

Operations and observability

An API in production must be watched: structured logs, latency and error metrics, threshold alerts, tested database backups. We deliver these with the API, not as an option, and we can keep an eye on them under a maintenance contract.

Stack & tools

  • Node.js 22
  • TypeScript
  • Fastify
  • Express
  • Prisma
  • PostgreSQL
  • Redis
  • BullMQ
  • Zod
  • Docker
  • Vitest
  • OpenAPI

Why ELDEV
Node.js

We have written Node.js for over ten years, in strict TypeScript since that became possible. We know when a simple Fastify server is enough and when a job queue, a cache or a replicated database is needed, and we never over-engineer out of caution. Every API we deliver comes with integration tests, OpenAPI documentation, a Dockerfile and a deployment pipeline: you can evolve it or hand it to another team without depending on us.

Frequently asked questions

Is Node.js suited to a data-heavy business application?
Yes, provided the database and processing are designed properly. Node excels at high-traffic APIs and real-time integrations; heavy computation is offloaded to job queues or dedicated services. We will tell you honestly if another language is a better fit.
Do you provide API documentation?
Always. Every route is described in OpenAPI, with a Swagger interface to try it and example calls. That is what lets the developer of your mobile app or a partner integrate your API without calling us.
How much does a custom API cost?
It depends on the number of entities, the integrations and the required security level. The free scoping call produces a precise quote: get in touch, reply within 12 hours.
Where is the API hosted?
On a VPS (Hetzner, OVH), as a container on a managed cloud (Render, Fly.io, AWS) or inside your existing infrastructure. See our hosting and infrastructure service: we choose together based on load, budget and data constraints.

Related service: Web Development

A project, an outage, a question?

Describe your need in a few lines. Free scoping, reply within 12 business hours, and a single point of contact from the first exchange to launch.

Describe my projectcontact@eldev.fr