Astro Integration API

Astro Integrations add new functionality and behaviors for your project with only a few lines of code.

This reference page is for anyone writing their own integration. To learn how to use an integration in your project, check out our Using Integrations guide instead.

Examples

Section titled Examples The official Astro integrations can act as reference for you as you go to build your own integrations.

• Renderers: lit, svelte, react, preact, vue, solid
• Libraries: tailwind, partytown
• Features: sitemap

Quick API Reference

Section titled Quick API Reference

interface AstroIntegration {  name: string;  hooks: {    'astro:config:setup'?: (options: {      config: AstroConfig;      command: 'dev' | 'build' | 'preview' | 'sync';      isRestart: boolean;      updateConfig: (newConfig: DeepPartial<AstroConfig>) => AstroConfig;      addRenderer: (renderer: AstroRenderer) => void;      addWatchFile: (path: URL | string) => void;      addClientDirective: (directive: ClientDirectiveConfig) => void;      addMiddleware: (middleware: AstroIntegrationMiddleware) => void;      addDevToolbarApp: (pluginEntrypoint: string) => void;      injectScript: (stage: InjectedScriptStage, content: string) => void;      injectRoute: (injectedRoute: { pattern: string, entrypoint: string }) => void;      logger: AstroIntegrationLogger;    }) => void | Promise<void>;    'astro:config:done'?: (options: {      config: AstroConfig;      setAdapter: (adapter: AstroAdapter) => void;      injectTypes: (injectedType: { filename: string; content: string }) => URL;      logger: AstroIntegrationLogger;      }) => void | Promise<void>;    'astro:route:setup'?: (options: { route: RouteOptions; logger: AstroIntegrationLogger; }) => void | Promise<void>;    'astro:server:setup'?: (options: { server: vite.ViteDevServer; logger: AstroIntegrationLogger; }) => void | Promise<void>;    'astro:server:start'?: (options: { address: AddressInfo; logger: AstroIntegrationLogger; }) => void | Promise<void>;    'astro:server:done'?: (options: { logger: AstroIntegrationLogger; }) => void | Promise<void>;    'astro:build:start'?: (options: { logger: AstroIntegrationLogger; }) => void | Promise<void>;    'astro:build:setup'?: (options: {      vite: ViteConfigWithSSR;      pages: Map<string, PageBuildData>;      target: 'client' | 'server';      logger: AstroIntegrationLogger;    }) => void | Promise<void>;    'astro:build:generated'?: (options: { dir: URL; logger: AstroIntegrationLogger; }) => void | Promise<void>;    'astro:build:ssr'?: (options: {        manifest: SerializedSSRManifest;        entryPoints: Map<RouteData, URL>;        logger: AstroIntegrationLogger;    }) => void | Promise<void>;    'astro:build:done'?: (options: { dir: URL; routes: RouteData[]; logger: AstroIntegrationLogger; }) => void | Promise<void>;
    // ... any custom hooks from integrations  };}

Hooks

Section titled Hooks Astro provides hooks that integrations can implement to execute during certain parts of Astro’s lifecycle. Astro hooks are defined in the IntegrationHooks interface, which is part of the global Astro namespace.

The following hooks are built in to Astro:

astro:config:setup

Section titled astro:config:setup Next hook: astro:config:done

When: On initialization, before either the Vite or Astro config have resolved.

Why: To extend the project config. This includes updating the Astro config, applying Vite plugins, adding component renderers, and injecting scripts onto the page.

'astro:config:setup'?: (options: {  config: AstroConfig;  command: 'dev' | 'build' | 'preview' | 'sync';  isRestart: boolean;  updateConfig: (newConfig: DeepPartial<AstroConfig>) => AstroConfig;  addRenderer: (renderer: AstroRenderer) => void;  addClientDirective: (directive: ClientDirectiveConfig) => void;  addMiddleware: (middleware: AstroIntegrationMiddleware) => void;  addDevToolbarApp: (pluginEntrypoint: string) => void;  addWatchFile: (path: URL | string) => void;  injectScript: (stage: InjectedScriptStage, content: string) => void;  injectRoute: ({ pattern: string, entrypoint: string }) => void;  logger: AstroIntegrationLogger;}) => void | Promise<void>;

config option

Section titled config option Type: AstroConfig

A read-only copy of the user-supplied Astro config. This is resolved before any other integrations have run. If you need a copy of the config after all integrations have completed their config updates, see the astro:config:done hook.

command option

Section titled command option Type: 'dev' | 'build' | 'preview' | 'sync'

• dev - Project is executed with astro dev
• build - Project is executed with astro build
• preview - Project is executed with astro preview
• sync - Project is executed with astro sync

isRestart option

Section titled isRestart option Type: boolean

false when the dev server starts, true when a reload is triggered. Useful to detect when this function is called more than once.

updateConfig option

Section titled updateConfig option Type: (newConfig: DeepPartial<AstroConfig>) => AstroConfig;

A callback function to update the user-supplied Astro config. Any config you provide will be merged with the user config + other integration config updates, so you are free to omit keys!

For example, say you need to supply a Vite plugin to the user’s project:

import bananaCSS from '@vitejs/official-banana-css-plugin';
export default {  name: 'banana-css-integration',  hooks: {    'astro:config:setup': ({ updateConfig }) => {      updateConfig({        vite: {          plugins: [bananaCSS()],        }      })    }  }}

addRenderer option

Section titled addRenderer option Type: (renderer: AstroRenderer ) => void; Examples: lit, svelte, react, preact, vue, solid

A callback function to add a component framework renderer (i.e. React, Vue, Svelte, etc). You can browse the examples and type definition above for more advanced options, but here are the 2 main options to be aware of:

• clientEntrypoint - path to a file that executes on the client whenever your component is used. This is mainly for rendering or hydrating your component with JS.
• serverEntrypoint - path to a file that executes during server-side requests or static builds whenever your component is used. These should render components to static markup, with hooks for hydration where applicable. React’s renderToString callback is a classic example.

addWatchFile option

Section titled addWatchFile option Type: URL | string

If your integration depends on some configuration file that Vite doesn’t watch and/or needs a full dev server restart to take effect, add it with addWatchFile. Whenever that file changes, the Astro dev server will be reloaded (you can check when a reload happens with isRestart).

Example usage:

// Must be an absolute path!addWatchFile('/home/user/.../my-config.json');addWatchFile(new URL('./tailwind.config.js', config.root));

addClientDirective option

Section titled addClientDirective option

Added in: astro@2.6.0

Type: (directive: ClientDirectiveConfig ) => void;

Adds a custom client directive to be used in .astro files.

Note that directive entrypoints are only bundled through esbuild and should be kept small so they don’t slow down component hydration.

Example usage:

astro.config.mjs

import { defineConfig } from 'astro/config';import clickDirective from './astro-click-directive/register.js'
// https://astro.build/configexport default defineConfig({  integrations: [    clickDirective()  ],});

astro-click-directive/register.js

/** * @type {() => import('astro').AstroIntegration} */export default () => ({  name: "client:click",  hooks: {    "astro:config:setup": ({ addClientDirective }) => {      addClientDirective({        name: "click",        entrypoint: "./astro-click-directive/click.js",      });    },  },});

astro-click-directive/click.js

/** * Hydrate on first click on the window * @type {import('astro').ClientDirective} */export default (load, opts, el) => {  window.addEventListener('click', async () => {    const hydrate = await load()    await hydrate()  }, { once: true })}

You can also add types for the directives in your library’s type definition file:

astro-click-directive/index.d.ts

import 'astro'declare module 'astro' {  interface AstroClientDirectives {    'client:click'?: boolean  }}

addDevToolbarApp option

Section titled addDevToolbarApp option

Added in: astro@3.4.0

Type: (pluginEntrypoint: string) => void;

Adds a custom dev toolbar app.

Example usage:

astro.config.mjs

import { defineConfig } from 'astro/config';import devToolbarIntegration from './astro-dev-toolbar-app/integration.js'
// https://astro.build/configexport default defineConfig({  integrations: [    devToolbarIntegration()  ],});

astro-dev-toolbar-app/integration.js

/** * @type {() => import('astro').AstroIntegration} */export default () => ({  name: "dev-toolbar-app",  hooks: {    "astro:config:setup": ({ addDevToolbarApp }) => {      addDevToolbarApp("./astro-dev-toolbar-app/plugin.js");    },  },});

astro-dev-toolbar-app/plugin.js

/** * @type {import('astro').DevToolbarApp} */export default {  id: "my-plugin",  name: "My Plugin",  icon: "<svg>...</svg>",  init() {    console.log("I'm a dev toolbar app!")  },};

addMiddleware option

Section titled addMiddleware option

Added in: astro@3.5.0

Type: (middleware: AstroIntegrationMiddleware ) => void;

Adds middleware to run on each request. Takes the entrypoint module that contains the middleware, and an order to specify whether it should run before (pre) other middleware or after (post).

@my-package/integration.js

/** * @type {() => import('astro').AstroIntegration} */export default () => ({  name: "my-middleware-package",  hooks: {    "astro:config:setup": ({ addMiddleware }) => {        addMiddleware({          entrypoint: '@my-package/middleware',          order: 'pre'        });    },  },});

Middleware is defined in a package with an onRequest function, as with user-defined middleware.

@my-package/middleware.js

import { defineMiddleware } from 'astro:middleware';
export const onRequest = defineMiddleware(async (context, next) => {  if(context.url.pathname === '/some-test-path') {    return Response.json({      ok: true    });  }
  return next();});

injectRoute option

Section titled injectRoute option Type: ({ pattern: string, entrypoint: string }) => void;

A callback function to inject routes into an Astro project. Injected routes can be .astro pages or .js and .ts route handlers.

injectRoute takes an object with a pattern and an entrypoint.

• pattern - where the route should be output in the browser, for example /foo/bar. A pattern can use Astro’s filepath syntax for denoting dynamic routes, for example /foo/[bar] or /foo/[...bar]. Note that a file extension is not needed in the pattern.
• entrypoint - a bare module specifier pointing towards the .astro page or .js/.ts route handler that handles the route denoted in the pattern.

Example usage

Section titled Example usage

injectRoute({  // Use Astro’s pattern syntax for dynamic routes.  pattern: '/subfolder/[dynamic]',  // Use relative path syntax for a local route.  entrypoint: './src/dynamic-page.astro'});

For an integration designed to be installed in other projects, use its package name to refer to the route entrypoint. The following example shows a package published to npm as @fancy/dashboard injecting a dashboard route:

injectRoute({  pattern: '/fancy-dashboard',  entrypoint: '@fancy/dashboard/dashboard.astro'});

When publishing your package (@fancy/dashboard, in this case) to npm, you must export dashboard.astro in your package.json:

package.json

{  "name": "@fancy/dashboard",  // ...  "exports": { "./dashboard.astro": "./dashboard.astro" }}

injectScript option

Section titled injectScript option Type: (stage: InjectedScriptStage, content: string) => void;

A callback function to inject a string of JavaScript content onto every page.

The stage denotes how this script (the content) should be inserted. Some stages allow inserting scripts without modification, while others allow optimization during Vite’s bundling step:

• "head-inline": Injected into a script tag in the <head> of every page. Not optimized or resolved by Vite.
• "before-hydration": Imported client-side, before the hydration script runs. Optimized and resolved by Vite.
• "page": Similar to head-inline, except that the injected snippet is handled by Vite and bundled with any other <script> tags defined inside of Astro components on the page. The script will be loaded with a <script type="module"> in the final page output, optimized and resolved by Vite.
• "page-ssr": Imported as a separate module in the frontmatter of every Astro page component. Because this stage imports your script, the Astro global is not available and your script will only be run once when the import is first evaluated.

The main use for the page-ssr stage is injecting a CSS import into every page to be optimized and resolved by Vite:

injectScript('page-ssr', 'import "global-styles.css";');

astro:config:done

Section titled astro:config:done Previous hook: astro:config:setup

Next hook: astro:server:setup when running in “dev” mode, or astro:build:start during production builds

When: After the Astro config has resolved and other integrations have run their astro:config:setup hooks.

Why: To retrieve the final config for use in other hooks.

'astro:config:done'?: (options: {  config: AstroConfig;  setAdapter: (adapter: AstroAdapter) => void;  injectTypes: (injectedType: { filename: string; content: string }) => URL;  logger: AstroIntegrationLogger;}) => void | Promise<void>;

config option

Section titled config option Type: AstroConfig

A read-only copy of the user-supplied Astro config. This is resolved after other integrations have run.

setAdapter option

Section titled setAdapter option Type: (adapter: AstroAdapter) => void;

Makes the integration an adapter. Read more in the adapter API.

injectTypes options

Section titled injectTypes options

Added in: astro@4.14.0

Type: (injectedType: { filename: string; content: string }) => URL

Allows you to inject types into your user’s project by adding a new *.d.ts file.

The filename property will be used to generate a file at /.astro/integrations/<normalized_integration_name>/<normalized_filename>.d.ts and must end with ".d.ts".

The content property will create the body of the file and must be valid TypeScript.

Additionally, injectTypes() returns a URL to the normalized path so you can overwrite its content later on, or manipulate it in any way you want.

const path = injectTypes({  filename: "types.d.ts",  content: "declare module 'virtual:integration' {}"})console.log(path) // URL

astro:server:setup

Section titled astro:server:setup Previous hook: astro:config:done

Next hook: astro:server:start

When: Just after the Vite server is created in “dev” mode, but before the listen() event is fired. See Vite’s createServer API for more.

Why: To update Vite server options and middleware.

'astro:server:setup'?: (options: { server: vite.ViteDevServer }) => void | Promise<void>;

server option

Section titled server option Type: ViteDevServer

A mutable instance of the Vite server used in “dev” mode. For instance, this is used by our Partytown integration to inject the Partytown server as middleware:

export default {  name: 'partytown',  hooks: {    'astro:server:setup': ({ server }) => {      server.middlewares.use(        function middleware(req, res, next) {          // handle requests        }      );    }  }}

astro:server:start

Section titled astro:server:start Previous hook: astro:server:setup

Next hook: astro:server:done

When: Just after the server’s listen() event has fired.

Why: To intercept network requests at the specified address. If you intend to use this address for middleware, consider using astro:server:setup instead.

'astro:server:start'?: (options: { address: AddressInfo }) => void | Promise<void>;

address option

Section titled address option Type: AddressInfo

The address, family and port number supplied by the Node.js Net module.

astro:server:done

Section titled astro:server:done Previous hook: astro:server:start

When: Just after the dev server is closed.

Why: To run any cleanup events you may trigger during the astro:server:setup or astro:server:start hooks.

'astro:server:done'?: () => void | Promise<void>;

astro:build:start

Section titled astro:build:start Previous hook: astro:config:done

Next hook: astro:build:setup

When: After the astro:config:done event, but before the production build begins.

Why: To set up any global objects or clients needed during a production build. This can also extend the build configuration options in the adapter API.

'astro:build:start'?: () => void | Promise<void>;

astro:build:setup

Section titled astro:build:setup Previous hook: astro:build:start

Next hook: astro:build:ssr

When: After the astro:build:start hook, runs immediately before the build.

Why: At this point, the Vite config for the build has been completely constructed, this is your final chance to modify it. This can be useful for example to overwrite some defaults. If you’re not sure whether you should use this hook or astro:build:start, use astro:build:start instead.

'astro:build:setup'?: (options: {  vite: ViteConfigWithSSR;  pages: Map<string, PageBuildData>;  target: 'client' | 'server';}) => void | Promise<void>;

astro:build:generated

Section titled astro:build:generated Previous hook: astro:build:setup

When: After a static production build has finished generating routes and assets.

Why: To access generated routes and assets before build artifacts are cleaned up. This is a very uncommon use case. We recommend using astro:build:done unless you really need to access the generated files before cleanup.

'astro:build:generated'?: (options: { dir: URL }) => void | Promise<void>;

astro:build:ssr

Section titled astro:build:ssr Previous hook: astro:build:setup

When: After a production SSR build has completed.

Why: To access the SSR manifest and map of the emitted entry points. This is useful when creating custom SSR builds in plugins or integrations.

• entryPoints maps a page route to the physical file emitted after the build;
• middlewareEntryPoint is the file system path of the middleware file;

'astro:build:ssr'?: (options: {    manifest: SerializedSSRManifest,    entryPoints: Map<RouteData, URL>,    middlewareEntryPoint: URL}) => void | Promise<void>;

astro:build:done

Section titled astro:build:done Previous hook: astro:build:ssr

When: After a production build (SSG or SSR) has completed.

Why: To access generated routes and assets for extension (ex. copy content into the generated /assets directory). If you plan to transform generated assets, we recommend exploring the Vite Plugin API and configuring via astro:config:setup instead.

'astro:build:done'?: (options: { dir: URL; routes: RouteData[], pages: { pathname: string }[] }) => void | Promise<void>;

dir option

Section titled dir option Type: URL

A URL path to the build output directory. Note that if you need a valid absolute path string, you should use Node’s built-in fileURLToPath utility.

import { writeFile } from 'node:fs/promises';import { fileURLToPath } from 'node:url';
export default function myIntegration() {  return {    hooks: {      'astro:build:done': async ({ dir }) => {        const metadata = await getIntegrationMetadata();        // Use fileURLToPath to get a valid, cross-platform absolute path string        const outFile = fileURLToPath(new URL('./my-integration.json', dir));        await writeFile(outFile, JSON.stringify(metadata));      }    }  }}

routes option

Section titled routes option Type: RouteData[]

A list of all generated routes alongside their associated metadata.

You can reference the full RouteData type below, but the most common properties are:

• component - the input file path relative to the project root
• pathname - the output file URL (undefined for routes using [dynamic] and [...spread] params)

RouteData type reference

Section titled RouteData type reference

interface RouteData {  /** Whether a given route is an HTML page or non-HTML endpoint */  type: 'page' | 'endpoint';  /** Source component URL */  component: string;  /**   * Output URL pathname where this route will be served   * note: will be undefined for [dynamic] and [...spread] routes   */  pathname?: string;  /**   * regex used for matching an input URL against a requested route   * ex. "[fruit]/about.astro" will generate the pattern: /^\/([^/]+?)\/about\/?$/   * where pattern.test("banana/about") is "true"   */  pattern: RegExp;  /**   * Dynamic and spread route params   * ex. "/pages/[lang]/[..slug].astro" will output the params ['lang', '...slug']   */  params: string[];  /**   * Similar to the "params" field, but with more associated metadata   * ex. "/pages/[lang]/index.astro" will output the segments   * [[ { content: 'lang', dynamic: true, spread: false } ]]   */  segments: { content: string; dynamic: boolean; spread: boolean; }[][];  /**   * Function to render component in-place from a set of input data.   * This is typically for internal use, so call with caution!   */  generate: (data?: any) => string;}

pages option

Section titled pages option Type: { pathname: string }[]

A list of all generated pages. It is an object with one property.

• pathname - the finalized path of the page.

astro:route:setup

Section titled astro:route:setup

Added in: astro@4.14.0

When: In astro dev, whenever a route is requested. In astro build, while bundling and transforming a route file.

Why: To set options for a route at build or request time, such as enabling on-demand server rendering.

'astro:route:setup'?: (options: { route: RouteOptions }) => void | Promise<void>;

route option

Section titled route option Type: RouteOptions

An object with a component property to identify the route and the following additional values to allow you to configure the generated route: prerender.

The component property is a readonly string path relative to the project root, e.g "src/pages/blog/[slug].astro".

route.prerender

Section titled route.prerender Type: boolean

Default: undefined

Added in: astro@4.14.0

The prerender property is used to configure on-demand server rendering for a route. If the route file contains an explicit export const prerender value, the value will be used as the default instead of undefined.

astro.config.mjs

import { defineConfig } from 'astro/config';
export default defineConfig({  integrations: [setPrerender()],});
function setPrerender() {  return {    name: 'set-prerender',    hooks: {      'astro:route:setup': ({ route }) => {        if (route.component.endsWith('/blog/[slug].astro')) {          route.prerender = true;        }      },    },  };}

If the final value after running all the hooks is undefined, the route will fall back to a prerender default based on the output option: prerendered for hybrid mode, and on-demand rendered for server mode.

Custom hooks

Section titled Custom hooks Custom hooks can be added to integrations by extending the IntegrationHooks interface through global augmentation.

declare global {  namespace Astro {    export interface IntegrationHook {      'your:hook': (params: YourHookParameters) => Promise<void>    }  }}

Astro reserves the astro: prefix for future built-in hooks. Please choose a different prefix when naming your custom hook.

HookParameters

Section titled HookParameters You can get the type of a hook’s arguments by passing the hook’s name to the HookParameters utility type. In the following example, a function’s options argument is typed to match the parameters of the astro:config:setup hook:

import type { HookParameters } from 'astro';
function mySetup(options: HookParameters<'astro:config:setup'>) {  options.updateConfig({ /* ... */ });}

Allow installation with astro add

Section titled Allow installation with astro add The astro add command allows users to easily add integrations and adapters to their project. If you want your integration to be installable with this tool, add astro-integration to the keywords field in your package.json:

{  "name": "example",  "keywords": ["astro-integration"],}

Once you publish your integration to npm, running astro add example will install your package with any peer dependencies specified in your package.json. This will also apply your integration to the user’s astro.config like so:

astro.config.mjs

import { defineConfig } from 'astro/config'; import example from 'example';
export default defineConfig({  integrations: [example()],})

Caution

This assumes your integration definition is 1) a default export and 2) a function. Ensure this is true before adding the astro-integration keyword!

AstroIntegrationLogger

Section titled AstroIntegrationLogger An instance of the Astro logger, useful to write logs. This logger uses the same log level configured via CLI.

Methods available to write to terminal:

• logger.info("Message");
• logger.warn("Message");
• logger.error("Message");
• logger.debug("Message");

All the messages are prepended with a label that has the same value of the integration.

integration.ts

import type { AstroIntegration } from "astro";export function formatIntegration(): AstroIntegration {    return {        name: "astro-format",        hooks: {            "astro:build:done": ({ logger }) => {                // do something                logger.info("Integration ready.");            }        }    }}

The example above will log a message that includes the provided info message:

Terminal window

[astro-format] Integration ready.

To log some messages with a different label, use the .fork method to specify an alternative to the default name:

integration.ts

import type { AstroIntegration } from "astro";export function formatIntegration(): AstroIntegration {    return {        name: "astro-format",        hooks: {            "astro:config:done": ({ logger }) => {                // do something                logger.info("Integration ready.");            },            "astro:build:done": ({ logger }) => {                const buildLogger = logger.fork("astro-format/build");                // do something                buildLogger.info("Build finished.")            }        }    }}

The example above will produce logs with [astro-format] by default, and [astro-format/build] when specified:

Terminal window

[astro-format] Integration ready.[astro-format/build] Build finished.

Integration Ordering

Section titled Integration Ordering All integrations are run in the order that they are configured. For instance, for the array [react(), svelte()] in a user’s astro.config.*, react will run before svelte.

Your integration should ideally run in any order. If this isn’t possible, we recommend documenting that your integration needs to come first or last in your user’s integrations configuration array.

Combine integrations into presets

Section titled Combine integrations into presets An integration can also be written as a collection of multiple, smaller integrations. We call these collections presets. Instead of creating a factory function that returns a single integration object, a preset returns an array of integration objects. This is useful for building complex features out of multiple integrations.

integrations: [  // Example: where examplePreset() returns: [integrationOne, integrationTwo, ...etc]  examplePreset()]

Community Resources

Section titled Community Resources

• Build your own Astro Integrations - by Emmanuel Ohans on FreeCodeCamp
• Astro Integration Template - by Florian Lefebvre on GitHub

Reference