Webhooks

A webhook is a way of altering or augmenting a web application through HTTP methods. Previously, we used third-party APIs in our bots to get data into and out of Slack. However, this isn't the only way. Webhooks allow us to post message to and from Slack using regular HTTP requests with a JSON payload. What makes a webhook a bot is its ability to post messages to Slack as if they are a bot user.

These webhooks can be divided into incoming and outgoing webhooks, each with their own purposes and uses.

Incoming webhooks

An example of an incoming webhook would be a service that relays information from an external source to a Slack channel without being explicitly requested. An example of this is the aforementioned GitHub Slack integration:

The GitHub integration posts messages about repositories we are interested in

In the preceding screenshot, we can see how a message was sent to Slack after a new branch was made on a repository this team is watching. This data wasn't explicitly requested...