# How to use Deploy Hooks with Vercel and a Headless CMS **Author:** Lee Robinson --- Vercel provides a first-class integration with [GitHub](https://vercel.com/docs/concepts/git/vercel-for-github), [GitLab](https://vercel.com/docs/concepts/git/vercel-for-gitlab) and [BitBucket](https://vercel.com/docs/concepts/git/vercel-for-bitbucket) when deploying applications. You can push a commit to the [Git](https://vercel.com/docs/concepts/git) repository to deploy code changes to your app. In an application where the changes depend on external events, such as when content changes are made directly in a Headless Content Management System (CMS) or a database, you may want to trigger deployments without touching code automatically. Using Vercel [**Deploy Hooks**](https://vercel.com/docs/concepts/git/deploy-hooks) you can trigger deployments based on when the content changes in the CMS or database. This guide will walk you through creating a Deploy Hook and triggering a deployment without pushing commits to a Git repository when content changes are made directly from a Headless CMS. ## Prerequisites Before you begin with this guide, please make sure you have the following prerequisites: - Have an example app set up locally. This guide uses a statically generated Next.js [blog example](https://github.com/vercel/next.js/tree/canary/examples/cms-contentful) that comes pre-configured with Contentful as the data source - An [account](https://www.contentful.com/sign-up/) on Contentful - [Application deployed](https://github.com/vercel/next.js/tree/canary/examples/cms-contentful#step-8-deploy-on-vercel) on Vercel - Make sure your project is connected to a [Git repository](https://vercel.com/docs/concepts/projects/overview#git) when deployed To follow all the steps necessary in setting up Next.js and Contentful blog and how to add seed data from [this guide](https://github.com/vercel/next.js/tree/canary/examples/cms-contentful). ## Creating a Deploy Hook After you have deployed your app on Vercel, you will have to generate a new unique URL that will trigger deployment from Contentful. This unique URL is known as Deploy Hook. To create one: - Go to your [Vercel dashboard](https://vercel.com/dashboard) - Select the project you want to create the Deploy Hook for - Go to the Settings tab and then select Git from the menu item from the sidebar - In the **Deploy Hooks** section, add a name for your Deploy Hook - Then, add the branch name that is used want to trigger a deployment. For example, if your application uses GitHub integration, the branch might be `main` - Click the _Create Hook_ button to generate the Deploy Hook URL Press the _copy_ button next to the generated URL to copy the URL. ## Setting up a Webhook on Contentful The Deploy Hook URL on Vercel will act as the endpoint. When a content change is published in the CMS, it has to tell Vercel that there is a new change and a deployment should get triggered. To trigger the deployment on Vercel, you need to set up a webhook on Contentful to send the information about changes to the Deploy Hook URL. To create a webhook on Contentful: - From your Contentful dashboard, go to Settings from the top menu - In the dropdown menu, select _Webhooks_ - This will open a page where you can view previously created webhooks or create a new one - Contentful provides a Webhook template for Vercel. This makes the webhook creation process much easier - Select the Vercel's template from the list of templates and click the _add_ button - After clicking the _add_ button, a modal pops up - In this modal, paste the Deploy Hook URL in the input field under the section **Vercel deploy hook URL** and click the button _Create webhook_ ## Modifying Webhook settings You can control the triggering automatic deployments in Contentful based on content events. The webhook will trigger deployment by default when a content entry or an asset is published or unpublished. For this example, you can set the webhook to trigger a deployment when an entry or an asset is deleted. - From the Webhooks page, go to Webhook settings - Under _Content Events_, check the boxes under a Deleted column - Click the _Save_ button to apply modified settings ## Testing the Deploy Hook Let's create a new post in the Contentful CMS to test out the deployment. Right now, it has only two posts published: Add a new entry and publish it. This will trigger a deployment on Vercel. After successful deployment, the changes are reflected on the Next.js blog. ## Conclusion With Deploy Hooks, you can deploy based on any event or use any Headless CMS as a data source. However, your entire application is rebuilt on each deployment. This is not ideal for large applications. If your application has thousands of pages or more, then rebuilding the whole application will have longer build times. [Incremental Static Regeneration](https://vercel.com/docs/concepts/incremental-static-regeneration/overview) (ISR) is a better option for large applications to keep the build times low. Using ISR, you can take advantage of incrementally rebuilding pages that are affected by an update or new addition, instead of rebuilding the entire application on every change. --- [View full KB sitemap](/kb/sitemap.md)