REST API Development

Well-documented, versioned REST APIs built for real production load, designed to be easy for other developers and systems to integrate against.

API & Integrations

REST API Development

req/s, zero deadlocks
15Kreq/s, zero deadlocks
double-charges in production
0double-charges in production
production systems shipped
10+production systems shipped
years building for clients
7+years building for clients
Sound familiar

Signs you need this now.

A lot of APIs get built fast to unblock a feature and never get revisited, leaving inconsistent endpoints, no versioning, and documentation that's already out of date. That works fine until a second consumer, a partner integration, or a scaling event exposes exactly how fragile it is.

01

An API only one person understands

Endpoints were added ad hoc over time with no consistent structure, and the person who built it is the only one who can safely change it. That's a single point of failure sitting in the middle of your product.

02

Breaking changes that blindside integrators

A field gets renamed or removed without versioning, and every client consuming the API breaks at the same time with no warning. Rebuilding that trust with partners or internal teams takes far longer than building the fix would have.

03

Performance that falls apart under real traffic

An API that worked fine in testing starts timing out or returning errors once real concurrent load hits it. Without proper caching, pagination, and rate limiting from the start, scaling becomes a rebuild instead of a tuning exercise.

Scope

What you get.

Consistent, RESTful resource design

Endpoints follow predictable naming, status codes, and response structures, so any developer can guess how the rest of the API behaves after seeing a few endpoints.

API versioning strategy

A versioning approach is built in from the start, so future changes can ship without breaking existing consumers on older versions.

Authentication and rate limiting

API keys, OAuth, or token-based auth are implemented alongside rate limiting, so the API is protected from abuse and unauthorized access from day one.

Auto-generated, always-current documentation

Interactive documentation is generated directly from the code using OpenAPI/Swagger, so docs never drift out of sync with what the API actually does.

Error handling and validation built in

Every endpoint returns structured, predictable error responses with input validation applied consistently, so client apps can handle failures gracefully.

Load and performance testing

The API is tested under realistic concurrent load before launch, so performance issues surface in testing rather than in front of real users.

How it works

Four steps, no mystery.

01

Quick scoping call

A short call (or async over WhatsApp) to understand what you're working with and what "done" actually looks like for you.

02

Fixed scope, no surprises

A clear written plan of what's included and how long it takes, before any work starts.

03

The actual work

Progress you can see, not a black box. You get updates as milestones land, not just a status report at the end.

04

Handover

Everything documented and handed over cleanly, with a walkthrough so your team isn't stuck waiting on me for routine changes.

Questions

Frequently asked.

Most commonly Node.js with NestJS or Express, though the stack is chosen based on what fits your existing infrastructure and team.

Start here

Tell me what you're dealing with.

Send a message and get a real reply within 24 hours, not an automated sequence.

Prefer email? info@hasnain.io

Or WhatsApp directly, same link as above