How do I create a GitLab webhook?

I've read that GitLab is capable of sending messages to other servers via "web hooks" but I can't find where one would create one.

Can someone point me in the right direction?

All the answers I've found in official documentation and on Stack Overflow for finding web hooks are incorrect. The admin area > hooks page does NOT contain web hooks. It contains system hooks, which fire when you create/delete projects and users and things like that. This is not what you want.

To find your web hooks, go to the specific project > settings > web hooks (on sidebar in GitLab 6.1.0) page. These will fire on post-receive for the project in question. You can use a service like RequestBin to see what the payload looks like and to ensure you're firing these off correctly for debugging purposes.

With version 8.16.1, I found the web hooks under

specific project > settings > integrations

For group level hooks:

visit: https://gitlab.com/groups/<yourgroup>/hooks

For group project level hooks:

visit: https://gitlab.com/yourgroup/yourproject/hooks

You can see an example of GitLab system hook, with a web_hook.rb creation in this GitHub project.

In gitlab, as admin, go to "Hooks" tab, create hook as: http://your.ip.goes.here:8000

or change the port on line 175 of the script.

For web hooks, see Jamey's more accurate answer.

You can inspect the result of a webhook with a service like RequestBin.
Another example of webhook interpretation: this question.

Be aware though that a few issues remain with gitlab webhook:

• it is not always firing
• There's no URL nor namespace key present on system's webhook

I recommend using GitLabForm - configuration as code tool for GitLab - to configure webhooks with code like this:

project_settings:
  my_group/my_project:
    hooks:
      hooks:
      'http://127.0.0.1:5000/hooks/my-hook-endpoint':
        push_events: false # this is set to true by GitLab API by default
        merge_requests_events: true
        token: some_secret_auth_token

Disclosure: I wrote this tool and my company open-sourced it.