JS/TS backends

APIs that ship as fast as your front end.

Type-safe APIs and services in JavaScript and TypeScript on Node.js, Bun or Deno — one language across frontend and backend, shipped fast and built to scale. Free working prototype in 1 day, then a production release at a fixed price and date.

ExpressFastifyHonoNestJS

Get your free prototype 30-min call · no commitment

api · production

GET  /orders/4821        200 12ms
POST /checkout           201 48ms
GET  /users/me           200  8ms
POST /webhooks/stripe    200 15ms
GET  /products?page=2    200 21ms
POST /cart/items         201 11ms

p95 latency18 ms

● all systems normal

routes/orders.tsAI

const app = new Hono()

app.get('/orders/:id', async (c) => {

const order = await db.order.find(

c.req.param('id'))

return c.json(order)

})

Senior review · approved

Pipelinemain

Build
Testspassed
Senior review
Stagingload-tested
Productionlive

Buildto launch

Day 1Week 1Week 2Week 3Live

API v1 is livep95 latency 18 msnow

At a glance

One product. One price, one date.

The essentials, before you book a call.

UDEX builds JS/TS backends for founders and product teams. Type-safe APIs and services in JavaScript and TypeScript on Node.js, Bun or Deno — one language across frontend and backend, shipped fast and built to scale. AI writes the code, tests and CI/CD, while senior engineers own the architecture and review every change.

1 dayFree prototypeNo payment, no commitment

FixedPrice and dateAgreed before we start

100%YoursCode, repository and accounts

Platform: Backend and APIs on Node.js, Bun or Deno
Ships to: Production
Stack: ExpressFastifyHonoNestJS
Quality: Senior review on every change, automated tests, CI/CD

How it works

Idea to production. In three steps.

AI does the heavy lifting. Senior engineers make every decision that matters.

01Day 0
Share the idea
A 30-minute call. We agree on the core flow, the scope and a fixed release date.
02Day 1 → release
AI builds, senior engineers decide
AI writes the code, tests and CI/CD. Senior engineers set the architecture and review every change. Your prototype is ready on day 1.
03Release day
Ship to production
The release goes live, and the code, repository and accounts are handed to you.

Who it’s for

Built for founders and product teams.

Here is where it works best, and where it doesn’t.

Teams with a TypeScript front end

One language and shared types end to end.

Products with many integrations

Webhooks, payments and third-party APIs.

Mobile apps that need a backend

Auth, data and push notifications.

Event-driven products

Queues, jobs and scheduled tasks.

Startups outgrowing BaaS

Move from Firebase or Supabase limits to your own API.

Teams splitting a monolith

Extract services without a big-bang rewrite.

Not the right fit

CPU-heavy number crunching: see Rust or Go backends.
Pure data science workloads: see Python backends.
Certified compliance from day one, such as HIPAA or PCI audits.
Open-ended hourly work without a defined first release.

How we work

Six stages, one team.

All services

Pricing

Start free. Ship at a fixed price.

Two steps. The prototype costs nothing, and the release costs exactly what we agree.

Prototype

Free1 day

A working prototype of your core flow to test with users and show investors.

Key screens and the main user flow
Working on real devices and browsers
No payment, no commitment

Get the free prototype

Release

Fixed priceand date, agreed upfront

A production release, shipped to production, that you fully own.

Express, Fastify, Hono and the features agreed on the call
Automated tests, CI/CD and senior code review
Release to production and 100% code ownership

Start with a call

Fixed means fixed. No hourly billing and no surprise invoices: anything new is priced before it is built.

Book a call

Thirty minutes. Then your prototype.

Walk us through the idea, and we will scope the core flow and build your free prototype the next day.

Book a 30-min call

FAQ

Questions, answered.

Straight answers about cost, timing, quality and ownership.

How much does it cost to build a JS/TS backend?

The price is fixed for the agreed scope and set before work starts. You first get a free working prototype of the core flow in 1 day, then a fixed price and release date for the production version.

How long does it take to build a JS/TS backend?

A working prototype takes 1 day. The production release date is agreed upfront and depends on the scope; AI speed with senior engineering makes it much faster than classic development.

Express, Fastify, Hono or NestJS?

Hono or Fastify for lean, fast APIs, NestJS for large structured systems, Express when you already use it. We pick together on the call.

Will the API be documented?

Yes. OpenAPI documentation and typed clients are generated from the code.

Where does it run?

On your cloud: AWS, Google Cloud, Fly.io or serverless platforms, under your accounts.

Is the prototype really free?

Yes, with no commitment. After a 30-minute call we build a working prototype of your core flow in 1 day, and then you decide whether to continue to the release.

Will the price go up during the build?

No. The price is fixed for the agreed scope. Anything new you want to add mid-build is priced separately and built only after you approve it.

Who owns the code?

You do, 100%. The source code, repository and accounts are yours, and the release ships to production under your name.

Is AI-written code safe to ship to production?

It ships only after senior review. Senior engineers own the architecture, security and code quality, and automated tests run on every change.

In practice