There are two essential concepts for integration today: APIs and events.

APIs allow for reading and writing data, calling functionality and starting processes. APIs connect us with actuators in the digital world that enable us to do and change things.

Events allow for reacting to things happening in the environment. Events connect us with sensors in the digital world that wake us up, tell us that things have changed and what exactly has changed.

APIs are the hands, events are the eyes. Life is much easier when we have both. Hands without eyes allow for blind action only – and eyes without hands allow us to see what needs to be done and when it needs to be done – without being able to carry out the necessary change.

The same is true for APIs and events: APIs without events let us manipulate data, but not react to changes. Events without APIs let us pile up log data and even run analytics on it but without the capacity to act on the changes. If we want our APIs to be used, we need to provide both APIs and events – both hands and eyes to our consumers.

Hands and eyes are necessary to play the game. To win the game, however, hands and eyes need to be well-coordinated. Providing events which are well-coordinated with the available APIs is a competitive advantage for API providers and allows them to differentiate.

How do we realize events in an API context? What does coordination between APIs and events mean? ​In the new book, we give some concrete answers to these questions. We show how to make webhooks work in a RESTful API portfolio with some detailed design proposals in OpenAPI.

APIs and Events are the Hands and Eyes
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Matthias Biehl

As API strategist, Matthias helps clients discover their opportunities for innovation with APIs & ecosystems and turn them into actionable digital strategies. Based on his experience in leading large-scale API initiatives in both business and technology roles, he shares best practices and provides both strategic and practical guidance. He has stayed a techie at heart and at some point, got a Ph.D. Matthias publishes a blog at, is the author of several books on APIs, and regularly speaks at technology conferences.