REST API Development

REST APIs in plain words

A REST API is a set of web addresses that other software uses to read and change your data. Your mobile app calls it to show a customer’s orders. Your website calls it to create a booking. A partner’s system calls it to check stock. Each request follows the same conventions — resources like “orders” or “customers”, standard methods for reading, creating, updating and deleting, and standard status codes to say what happened.

The value of an API comes from predictability. Developers integrating with it should be able to guess how a new endpoint works because it behaves like the others.

When a business needs a REST API

• You are launching a mobile app and it needs a backend to talk to.
• A SaaS startup wants customers to integrate programmatically, not just through the dashboard.
• A logistics firm needs to exchange shipment data with clients’ ERPs and courier partners.
• A real estate agency wants its listings available to its website, a WhatsApp bot and partner portals from one source.
• Several internal tools need the same data, and you want one place where the rules are enforced.

What’s built in from the first endpoint

The things that make an API trustworthy are hard to add later, so we include them from the start:

• Consistent resource design — naming, pagination, filtering and error formats that work the same way everywhere.
• Input validation on every request, with clear error messages that tell the caller exactly which field is wrong.
• Correct status codes, so clients can handle success, not-found, validation errors and permission errors properly.
• Authentication and authorisation using API keys, tokens or OAuth, with checks on what each caller is allowed to access.
• Versioning, so you can improve the API without breaking integrations that depend on the current behaviour.
• Rate limiting to protect the service from runaway clients.
• Contract tests that confirm responses keep their shape, so a refactor doesn’t quietly break someone’s integration.
• Documentation generated from the code, typically as an OpenAPI specification with an interactive explorer.

How we deliver an API

1. List the consumers. Who will call the API, and what do they need to do? A mobile app and a partner integration have different needs.
2. Draft the contract. We write the endpoint list and request/response shapes first, and review them with you and any external developers.
3. Implement and test. Endpoints are built against the agreed contract, with tests for normal and error cases.
4. Publish documentation and a sandbox. Integrators can try requests safely before touching real data.
5. Launch with monitoring. Response times, error rates and usage are logged so problems surface early.

Technology choices

What shapes timeline and cost

• The number of resources and how complex the rules behind each one are.
• Authentication requirements — internal-only access is simpler than public OAuth for third-party developers.
• Whether the API sits on a new database or has to wrap an existing, sometimes messy, one.
• Expected traffic and response-time targets.
• How much documentation, sandbox and developer support external integrators need.

Mistakes that cause trouble later

• Returning 200 for everything and hiding errors in the response body, which forces every client to write special handling.
• No versioning plan, so the first breaking change becomes a coordination headache with every integrator.
• Trusting input from clients, which opens the door to bad data and security issues.
• Exposing database structure directly, which ties clients to internal details you will want to change.
• Documentation written once and never updated. Generating it from code keeps it honest.

Looking after an API once it’s live

An API is never really finished. New consumers appear, requirements shift, and the endpoints that seemed minor at launch turn out to carry most of the traffic. Planning for that from the start keeps changes calm rather than urgent.

• Deprecation policy — when an older version will be retired, and how integrators will be told in advance.
• Changelog — a plain record of what changed in each release, so consumers are never surprised.
• Usage monitoring — which endpoints and clients are busiest, which helps decide what to optimise first.
• Security updates for the framework and dependencies, applied on a regular schedule rather than only after a problem.

We can take this on through ongoing maintenance, or document it clearly so your own team can run it.

Frequently asked questions