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. It replaces manual retyping with an automatic data flow that runs continuously or at set moments.
API integrations in practice
An integration can take three forms: a ready-made standard connector from a vendor, a flow in an integration platform (iPaaS) such as Make or Power Automate, or custom work built directly on the APIs of both systems. That order is also the order of cost and flexibility: standard is cheap but limited, custom is more expensive but follows your process exactly.
Custom work costs roughly €1,500 to €15,000 one-off, depending on the number of systems and the logic between them; a webshop-to-accounting integration usually sits at the lower end. The full price breakdown is in What does an API integration cost?; per system combination we compare the options on the integrations pages.
Related terms
- API — An API (Application Programming Interface) is a standardised way for software systems to make data and functions available to one another.
- iPaaS — iPaaS (integration Platform as a Service) is a cloud service that lets you connect software systems without building or hosting integration software yourself.
- Middleware — Middleware is software that sits between two or more systems and manages the traffic between them: fetching data, translating it into the right format and delivering it to the target system.
- 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.