---
title: next CLI
description: Learn how to run and build your application with the Next.js CLI.
---
{/* The content of this doc is shared between the app and pages router. You can use the `Content` component to add content that is specific to the Pages Router. Any shared content should not be wrapped in a component. */}
The Next.js CLI allows you to develop, build, start your application, and more.
Basic usage:
```bash filename="Terminal"
npx next [command] [options]
```
## Reference
The following options are available:
| Options | Description |
| ------------------- | ---------------------------------- |
| `-h` or `--help` | Shows all available options |
| `-v` or `--version` | Outputs the Next.js version number |
### Commands
The following commands are available:
| Command | Description |
| -------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| [`dev`](#next-dev-options) | Starts Next.js in development mode with Hot Module Reloading, error reporting, and more. |
| [`build`](#next-build-options) | Creates an optimized production build of your application. Displaying information about each route. |
| [`start`](#next-start-options) | Starts Next.js in production mode. The application should be compiled with `next build` first. |
| [`info`](#next-info-options) | Prints relevant details about the current system which can be used to report Next.js bugs. |
| [`lint`](#next-lint-options) | Runs ESLint for all files in the `/src`, `/app`, `/pages`, `/components`, and `/lib` directories. It also provides a guided setup to install any required dependencies if ESLint it is not already configured in your application. |
| [`telemetry`](#next-telemetry-options) | Allows you to enable or disable Next.js' completely anonymous telemetry collection. |
> **Good to know**: Running `next` without a command is an alias for `next dev`.
### `next dev` options
`next dev` starts the application in development mode with Hot Module Reloading (HMR), error reporting, and more. The following options are available when running `next dev`:
| Option | Description |
| ---------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------- |
| `-h, --help` | Show all available options. |
| `[directory]` | A directory in which to build the application. If not provided, current directory is used. |
| `--turbopack` | Starts development mode using [Turbopack](/docs/app/api-reference/turbopack). |
| `-p` or `--port ` | Specify a port number on which to start the application. Default: 3000, env: PORT |
| `-H`or `--hostname ` | Specify a hostname on which to start the application. Useful for making the application available for other devices on the network. Default: 0.0.0.0 |
| `--experimental-https` | Starts the server with HTTPS and generates a self-signed certificate. |
| `--experimental-https-key ` | Path to a HTTPS key file. |
| `--experimental-https-cert ` | Path to a HTTPS certificate file. |
| `--experimental-https-ca ` | Path to a HTTPS certificate authority file. |
| `--experimental-upload-trace ` | Reports a subset of the debugging trace to a remote HTTP URL. |
### `next build` options
`next build` creates an optimized production build of your application. The output displays information about each route. For example:
```bash filename="Terminal"
Route (app) Size First Load JS
┌ ○ /_not-found 0 B 0 kB
└ ƒ /products/[id] 0 B 0 kB
○ (Static) prerendered as static content
ƒ (Dynamic) server-rendered on demand
```
- **Size**: The size of assets downloaded when navigating to the page client-side. The size for each route only includes its dependencies.
- **First Load JS**: The size of assets downloaded when visiting the page from the server. The amount of JS shared by all is shown as a separate metric.
Both of these values are [**compressed with gzip**](/docs/app/api-reference/config/next-config-js/compress). The first load is indicated by green, yellow, or red. Aim for green for performant applications.
The following options are available for the `next build` command:
| Option | Description |
| ---------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------- |
| `-h, --help` | Show all available options. |
| `[directory]` | A directory on which to build the application. If not provided, the current directory will be used. |
| `-d` or `--debug` | Enables a more verbose build output. With this flag enabled additional build output like rewrites, redirects, and headers will be shown. |
| |
| `--profile` | Enables production [profiling for React](https://react.dev/reference/react/Profiler). |
| `--no-lint` | Disables linting. |
| `--no-mangling` | Disables [mangling](https://en.wikipedia.org/wiki/Name_mangling). This may affect performance and should only be used for debugging purposes. |
| `--experimental-app-only` | Builds only App Router routes. |
| `--experimental-build-mode [mode]` | Uses an experimental build mode. (choices: "compile", "generate", default: "default") |
| `--debug-prerender` | Debug prerender errors in development. |
### `next start` options
`next start` starts the application in production mode. The application should be compiled with [`next build`](#next-build-options) first.
The following options are available for the `next start` command:
| Option | Description |
| --------------------------------------- | --------------------------------------------------------------------------------------------------------------- |
| `-h` or `--help` | Show all available options. |
| `[directory]` | A directory on which to start the application. If no directory is provided, the current directory will be used. |
| `-p` or `--port ` | Specify a port number on which to start the application. (default: 3000, env: PORT) |
| `-H` or `--hostname ` | Specify a hostname on which to start the application (default: 0.0.0.0). |
| `--keepAliveTimeout ` | Specify the maximum amount of milliseconds to wait before closing the inactive connections. |
### `next info` options
`next info` prints relevant details about the current system which can be used to report Next.js bugs when opening a [GitHub issue](https://github.com/vercel/next.js/issues). This information includes Operating System platform/arch/version, Binaries (Node.js, npm, Yarn, pnpm), package versions (`next`, `react`, `react-dom`), and more.
The output should look like this:
```bash filename="Terminal"
Operating System:
Platform: darwin
Arch: arm64
Version: Darwin Kernel Version 23.6.0
Available memory (MB): 65536
Available CPU cores: 10
Binaries:
Node: 20.12.0
npm: 10.5.0
Yarn: 1.22.19
pnpm: 9.6.0
Relevant Packages:
next: 15.0.0-canary.115 // Latest available version is detected (15.0.0-canary.115).
eslint-config-next: 14.2.5
react: 19.0.0-rc
react-dom: 19.0.0
typescript: 5.5.4
Next.js Config:
output: N/A
```
The following options are available for the `next info` command:
| Option | Description |
| ---------------- | ---------------------------------------------- |
| `-h` or `--help` | Show all available options |
| `--verbose` | Collects additional information for debugging. |
### `next lint` options
`next lint` runs ESLint for all files in the `pages/`, `app/`, `components/`, `lib/`, and `src/` directories. It also provides a guided setup to install any required dependencies if ESLint is not already configured in your application.
The following options are available for the `next lint` command:
| Option | Description |
| ----------------------------------------------------- | ------------------------------------------------------------------------------------------------------------- |
| `[directory]` | A base directory on which to lint the application. If not provided, the current directory will be used. |
| `-d, --dir, ` | Include directory, or directories, to run ESLint. |
| `--file, ` | Include file, or files, to run ESLint. |
| `--ext, [exts...]` | Specify JavaScript file extensions. (default: [".js", ".mjs", ".cjs", ".jsx", ".ts", ".mts", ".cts", ".tsx"]) |
| `-c, --config, ` | Uses this configuration file, overriding all other configuration options. |
| `--resolve-plugins-relative-to, ` | Specify a directory where plugins should be resolved from. |
| `--strict` | Creates a `.eslintrc.json` file using the Next.js strict configuration. |
| `--rulesdir, ` | Uses additional rules from this directory(s). |
| `--fix` | Automatically fix linting issues. |
| `--fix-type ` | Specify the types of fixes to apply (e.g., problem, suggestion, layout). |
| `--ignore-path ` | Specify a file to ignore. |
| `--no-ignore ` | Disables the `--ignore-path` option. |
| `--quiet` | Reports errors only. |
| `--max-warnings [maxWarnings]` | Specify the number of warnings before triggering a non-zero exit code. (default: -1) |
| `-o, --output-file, ` | Specify a file to write report to. |
| `-f, --format, ` | Uses a specific output format. |
| `--no-inline-config` | Prevents comments from changing config or rules. |
| `--report-unused-disable-directives-severity ` | Specify severity level for unused eslint-disable directives. (choices: "error", "off", "warn") |
| `--no-cache` | Disables caching. |
| `--cache-location, ` | Specify a location for cache. |
| `--cache-strategy, [cacheStrategy]` | Specify a strategy to use for detecting changed files in the cache. (default: "metadata") |
| `--error-on-unmatched-pattern` | Reports errors when any file patterns are unmatched. |
| `-h, --help` | Displays this message. |
### `next telemetry` options
Next.js collects **completely anonymous** telemetry data about general usage. Participation in this anonymous program is optional, and you can opt-out if you prefer not to share information.
The following options are available for the `next telemetry` command:
| Option | Description |
| ------------ | --------------------------------------- |
| `-h, --help` | Show all available options. |
| `--enable` | Enables Next.js' telemetry collection. |
| `--disable` | Disables Next.js' telemetry collection. |
Learn more about [Telemetry](/telemetry).
## Examples
### Debugging prerender errors
If you encounter prerendering errors during `next build`, you can pass the `--debug-prerender` flag to get more detailed output:
```bash filename="Terminal"
next build --debug-prerender
```
This enables several experimental options to make debugging easier:
- Disables server code minification:
- `experimental.serverMinification = false`
- `experimental.turbopackMinify = false`
- Generates source maps for server bundles:
- `experimental.serverSourceMaps = true`
- Enables source map consumption in child processes used for prerendering:
- `experimental.enablePrerenderSourceMaps = true`
- Continues building even after the first prerender error, so you can see all issues at once:
- `experimental.prerenderEarlyExit = false`
This helps surface more readable stack traces and code frames in the build output.
> **Warning**: `--debug-prerender` is for debugging in development only. Do not deploy builds generated with `--debug-prerender` to production, as it may impact performance.
### Changing the default port
By default, Next.js uses `http://localhost:3000` during development and with `next start`. The default port can be changed with the `-p` option, like so:
```bash filename="Terminal"
next dev -p 4000
```
Or using the `PORT` environment variable:
```bash filename="Terminal"
PORT=4000 next dev
```
> **Good to know**: `PORT` cannot be set in `.env` as booting up the HTTP server happens before any other code is initialized.
### Using HTTPS during development
For certain use cases like webhooks or authentication, you can use [HTTPS](https://developer.mozilla.org/en-US/docs/Glossary/HTTPS) to have a secure environment on `localhost`. Next.js can generate a self-signed certificate with `next dev` using the `--experimental-https` flag:
```bash filename="Terminal"
next dev --experimental-https
```
With the generated certificate, the Next.js development server will exist at `https://localhost:3000`. The default port `3000` is used unless a port is specified with `-p`, `--port`, or `PORT`.
You can also provide a custom certificate and key with `--experimental-https-key` and `--experimental-https-cert`. Optionally, you can provide a custom CA certificate with `--experimental-https-ca` as well.
```bash filename="Terminal"
next dev --experimental-https --experimental-https-key ./certificates/localhost-key.pem --experimental-https-cert ./certificates/localhost.pem
```
`next dev --experimental-https` is only intended for development and creates a locally trusted certificate with [`mkcert`](https://github.com/FiloSottile/mkcert). In production, use properly issued certificates from trusted authorities.
### Configuring a timeout for downstream proxies
When deploying Next.js behind a downstream proxy (e.g. a load-balancer like AWS ELB/ALB), it's important to configure Next's underlying HTTP server with [keep-alive timeouts](https://nodejs.org/api/http.html#http_server_keepalivetimeout) that are _larger_ than the downstream proxy's timeouts. Otherwise, once a keep-alive timeout is reached for a given TCP connection, Node.js will immediately terminate that connection without notifying the downstream proxy. This results in a proxy error whenever it attempts to reuse a connection that Node.js has already terminated.
To configure the timeout values for the production Next.js server, pass `--keepAliveTimeout` (in milliseconds) to `next start`, like so:
```bash filename="Terminal"
next start --keepAliveTimeout 70000
```
### Passing Node.js arguments
You can pass any [node arguments](https://nodejs.org/api/cli.html#cli_node_options_options) to `next` commands. For example:
```bash filename="Terminal"
NODE_OPTIONS='--throw-deprecation' next
NODE_OPTIONS='-r esm' next
NODE_OPTIONS='--inspect' next
```
| Version | Changes |
| --------- | ------------------------------------------------------------------------------- |
| `v15.4.0` | Add `--debug-prerender` option for `next build` to help debug prerender errors. |