Custom API development that your apps and partners can build on for years.

Custom API development is designing and building your own API — the set of endpoints, or the GraphQL schema, that lets other software talk to your systems in a controlled, secure way. An API is the doorway your software offers to the outside world; building a custom one means that doorway is shaped exactly around your data and your rules, rather than forced to fit an off-the-shelf tool. It is how your mobile app reaches your backend, how a partner plugs into your platform, and how your own services talk to each other cleanly.

Custom API development covers the whole job: designing the contract, choosing REST or GraphQL, building it securely, versioning it so it can change without breaking, documenting it, and supporting it after launch. Avaib has delivered software across more than 600 projects since 2004, and applies that same engineering discipline to building APIs that are consistent, secure and built to evolve.

It depends on how large the API is and how many clients it has to serve. A single backend API for one app is a small fixed-price job; a documented, versioned public API for partners is a larger project. Avaib's model is senior expertise at a cost-effective rate, typically around USD 25 per hour, which is why businesses in Australia, the US, Canada and the Middle East work with us instead of paying big-firm prices.

The real cost of an API is felt later: a badly built one is expensive forever because everything depends on it. We build it right the first time, and after a short scoping conversation we will send you a free, no-obligation written estimate with a clear scope and a ballpark price.

REST suits most APIs: it is the familiar standard, it caches well, and it maps cleanly onto clear resources like orders, users and products. GraphQL earns its place when one API has to serve very different clients — say a data-heavy web app and a lean mobile app — and you want each to ask for exactly the data it needs, instead of over-fetching or making many round-trips.

GraphQL also brings more complexity and its own traps, so it is not automatically the better choice. We pick the style that fits your data and your clients, and we will tell you honestly when the simpler REST option is the right one rather than the fashionable one.

By versioning it from the very first release. Once your mobile app, a partner or a customer has built on an API, changing its shape can break all of them at once — unless there is a version to fall back on. We version from day one, so a new version can ship alongside the old one.

When something genuinely has to change, we keep the old version working for a clear deprecation window and give advance notice, so nobody building on you is caught out overnight. Designing the contract first is what makes this possible.

An API is a door into your systems, so security is designed in from the start, not added after a scare. We implement the right authentication for the job — OAuth, tokens or keys — encrypt data in transit, validate every input, and add rate limiting and access control so the API cannot be overwhelmed or abused.

Our QA department then tests the abuse cases, not just the happy path, so the ways an API is actually attacked are found and closed before it goes live.

You own it outright — the code, the design and the documentation. We build on open standards rather than proprietary middleware, so there is nothing you have to keep paying us for to keep it running.

That means you can maintain it in-house, hand it to another team, or extend it yourself later. The API is an asset on your books, not a dependency on ours.

Custom API development is building your own API, so your systems, apps and partners have a clean, secure doorway to talk to you. API integration is connecting to APIs that already exist — usually a third party's — so your software can talk to their tools.

They often go together: we might build a custom API for your product and, at the same time, integrate it with the outside services it relies on. Avaib does both under one team, so the pieces fit.

Yes. We generate interactive documentation — OpenAPI / Swagger — directly from the live API, so what the docs say always matches what the API actually does, with examples a developer can try.

That means your own team, a partner or a third-party developer can pick up the API and start building without a chain of emails back to us. Good documentation is part of the deliverable, not an afterthought.