vercel dev

The vercel dev command is used to replicate the Vercel deployment environment locally, allowing you to test your Serverless Functions, without requiring you to deploy each time a change is made.

If you're using a framework and your framework's Development Command already provides all the features you need, we recommend against using vercel dev.

In the case of Next.js, for example, the framework's Development Command (next dev) provides native support for Serverless Functions (placed in the pages/api directory), Redirects, Rewrites, Headers and more – so there's no need to use vercel dev. However, you can use vercel env pull, to download the Development Environment Variables defined in your Project Settings.

Frameworks like Gatsby, on the other hand, do not offer a Development Command that supports Serverless Functions, for example. In those cases, vercel dev acts as a helper that provides the necessary features and runs Gatsby's Development Command at the same time. In that case, you wouldn't use vercel env pull because the Development Environment Variables defined in your Project Settings are downloaded into memory.

vercel dev

Using the vercel dev command from the root of a project directory.

The following global options can be passed when using the vercel dev command:

• --debug
• --help

For more information on global options and their usage, refer to the options section.

These are options that only apply to the vercel dev command, therefore, more information is provided.

The --listen option, shorthand -l, can be used to specify which port vercel dev runs on.

vercel dev --listen 5005

Using the vercel dev command with the --listen option.

The --yes option can be used to skip questions you are asked when setting up a new project. The questions will be answered with the default scope and current directory for the project name and location.

vercel dev --yes

Using the vercel dev command with the --yes option.