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. Whereas with an API you have to ask for data periodically yourself (polling), a webhook pushes the event straight to the receiving system. Webhooks are therefore the basis of real-time integrations.
Webhook in practice
The difference with polling is significant in practice. A connection that asks every fifteen minutes 'are there any new orders?' is by definition behind and consumes an unnecessary number of requests. A webhook delivers the same order within seconds. For processes where speed matters — order processing, candidate follow-up, alerts on incidents — webhooks are therefore the default choice.
When setting this up, bear in mind that webhooks can also fail: if the receiving system is briefly unreachable, the message has to be re-sent or caught somewhere. Good integrations therefore combine webhooks with a safety net that retrieves missed messages afterwards. In the Flow Lab you can see what such an event-driven flow looks like.
Related terms
- API — An API (Application Programming Interface) is a standardised way for software systems to make data and functions available to each other.
- 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 (retrieve), POST (create), PUT (update) and DELETE (remove).
- API connection — An API connection is a link between two software systems that automatically exchange data via their APIs — for example orders from a webshop to the accounting system, or placements from an ATS to invoicing.
- iPaaS — iPaaS (integration Platform as a Service) is a cloud service that lets you connect software systems to each other without building or hosting integration software yourself.