A REST API is the most common way for web systems to share data. It builds on the general idea of an API and adds a clear set of rules: every piece of data is a resource with its own web address, and you interact with it using the standard verbs of the web, mainly read, create, update and delete.
A good way to picture it is a library catalogue. Each book has a fixed shelf location (its address), and you can look one up, add a new one, change its details or remove it using the same simple set of actions. A REST API works the same way: ask /customers/42 and you get customer 42 back, usually as JSON, a lightweight text format almost any system can read. Each of those addresses is called an endpoint.
Because the rules are well known and built on plain HTTP, REST APIs are easy to connect to from almost any language or tool. That is why so many platforms, from payment providers to CRMs, offer one.
Part of what makes them predictable is the status code that comes back with every response. A 200 means success, 404 means the resource was not found, and 401 means you are not allowed in. So a developer reading your API can often tell what went wrong without any extra documentation. The flip side is the classic REST limitation: one endpoint returns one fixed shape, so loading a busy screen can mean three or four separate calls. That is the gap GraphQL was built to close, though for most projects plain REST stays the simpler choice.
At TopDevs we design REST APIs that are predictable and well documented, so your systems and any third party can connect to them without guesswork.
