A REST API is an API that works according to the REST architecture: data is accessed as 'resources' via standard HTTP requests such as GET (read), POST (create), PUT (update) and DELETE (delete). It is the most widely used API style for web applications and SaaS systems, with responses usually in JSON format.
The REST API in practice
The strength of REST lies in its simplicity and predictability: every resource has its own address (for example /orders/1234) and the standard HTTP verbs determine what you do with it. As a result, almost every programming language and every integration platform can work with a REST API, and documentation is relatively easy to read — even for those who aren't developers.
When assessing software it pays to check whether there is a REST API and how complete it is: can you only read, or also create and update? Is there a limit on the number of requests? Those details determine what an integration can do later. How such an integration is set up is explained in What does an API integration cost?
Related terms
- API — An API (Application Programming Interface) is a standardised way for software systems to make data and functions available to each other.
- JSON — JSON (JavaScript Object Notation) is the standard data format in which systems exchange information via APIs.
- Webhook — A webhook is an automatic message that a system sends immediately when something happens — for example a new order, a paid invoice or a changed candidate status.
- OAuth — OAuth is the open standard that lets you give an application access to your data in another system without sharing your password.