An API (Application Programming Interface) is a standardised way for software systems to make data and functions available to one another. Via an API, one system can read data from or write data to another, without anyone having to retype anything. APIs are therefore the technical foundation of almost every integration between business systems.
APIs in practice
Almost every modern business system — accounting, CRM, webshop, ATS — has an API. That API describes exactly which data you can request or supply and in what format. A well-documented, open API is therefore an important selection criterion when buying software: it determines whether you can later connect the system to the rest of your organisation, or whether it stays an island.
In practice you notice the difference mostly in manual work. Without an integration, someone retypes orders, customers or candidates from one system to another; with an integration on the API, that flows automatically. What such an integration costs and what drives the price is covered in What does an API integration cost?
Related terms
- REST API — 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 (remove).
- Webhook — A webhook is an automatic message a system sends immediately when something happens — for example a new order, a paid invoice or a changed candidate status.
- API integration — An API integration is a connection between two software systems that exchange data automatically via their APIs — for example orders from a webshop to the accounting system, or placements from an ATS to invoicing.
- JSON — JSON (JavaScript Object Notation) is the standard data format in which systems exchange information via APIs.