What is Vercel Doctor?

Vercel Doctor is an open-source tool for Next.js projects that identifies patterns increasing your Vercel costs, such as long function durations, uncached routes, and unnecessary invocations.

How do I use Vercel Doctor?

You can run it via npx: `npx -y vercel-doctor@latest .`. Use `--verbose` for detailed reports.

Is Vercel Doctor free?

Yes, Vercel Doctor is completely free and open-source under the MIT license.

Configuration

Configure Vercel Doctor with a config file to ignore rules, files, and customize behavior.

Vercel Doctor works out of the box with zero configuration. When you need to customize behavior, you can add a config file.

Config file

Create a vercel-doctor.config.json in your project root:

{
  "ignore": {
    "rules": ["vercel-doctor/nextjs-link-prefetch-default"],
    "files": ["src/generated/**"]
  }
}

Alternatively, add a "vercelDoctor" key to your package.json:

{
  "vercelDoctor": {
    "ignore": {
      "rules": ["knip/exports"],
      "files": ["src/generated/**"]
    }
  }
}

If both exist, vercel-doctor.config.json takes precedence.

Options

Key	Type	Default	Description
`ignore.rules`	`string[]`	`[]`	Rule IDs to suppress, in `plugin/rule` format
`ignore.files`	`string[]`	`[]`	Glob patterns for file paths to skip
`lint`	`boolean`	`true`	Enable or disable billing lint rules
`deadCode`	`boolean`	`true`	Enable or disable dead code detection
`verbose`	`boolean`	`false`	Show file paths and line numbers per rule
`diff`	`boolean \| string`	`false`	Enable diff mode or pin a base branch

Ignoring rules

Use the plugin/rule format for rule IDs:

{
  "ignore": {
    "rules": [
      "vercel-doctor/nextjs-image-missing-sizes",
      "vercel-doctor/vercel-large-static-asset",
      "knip/exports"
    ]
  }
}

See the Rules pages for all available rule IDs.

Ignoring files

Use glob patterns to exclude files from scanning:

{
  "ignore": {
    "files": ["src/generated/**", "**/*.stories.tsx", "scripts/**"]
  }
}

CLI overrides

CLI flags always take precedence over config file values. For example, --verbose on the command line overrides "verbose": false in the config file.

Full example

{
  "ignore": {
    "rules": [
      "vercel-doctor/vercel-consider-bun-runtime",
      "vercel-doctor/vercel-avoid-platform-cron"
    ],
    "files": ["src/generated/**", "e2e/**"]
  },
  "lint": true,
  "deadCode": true,
  "verbose": false,
  "diff": "main"
}

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