The Webhooks service allows you to integrate other services on IFTTT with your DIY projects via simple web requests.
If you are looking for your URL key to create a Webhook Applet with, you can find it in your settings page for the service.
Note: You can't publish Applets you build that use the Webhooks service. It's for your personal use only.
If you're interested in building a service on IFTTT, visit the platform and become a partner.