{"pageProps":{"routes":[{"title":"Documentation","heading":true,"routes":[{"title":"Getting Started","path":"/docs/getting-started.md"},{"title":"Basic Features","open":true,"routes":[{"title":"Pages","path":"/docs/basic-features/pages.md"},{"title":"Data fetching","path":"/docs/basic-features/data-fetching.md"},{"title":"Built-in CSS Support","path":"/docs/basic-features/built-in-css-support.md"},{"title":"Static File Serving","path":"/docs/basic-features/static-file-serving.md"},{"title":"TypeScript","path":"/docs/basic-features/typescript.md"},{"title":"Environment Variables","path":"/docs/basic-features/environment-variables.md"}]},{"title":"Routing","routes":[{"title":"Introduction","path":"/docs/routing/introduction.md"},{"title":"Dynamic Routes","path":"/docs/routing/dynamic-routes.md"},{"title":"Imperatively","path":"/docs/routing/imperatively.md"},{"title":"Shallow Routing","path":"/docs/routing/shallow-routing.md"}]},{"title":"API Routes","routes":[{"title":"Introduction","path":"/docs/api-routes/introduction.md"},{"title":"Dynamic API Routes","path":"/docs/api-routes/dynamic-api-routes.md"},{"title":"API Middlewares","path":"/docs/api-routes/api-middlewares.md"},{"title":"Response Helpers","path":"/docs/api-routes/response-helpers.md"}]},{"title":"Deployment","path":"/docs/deployment.md"},{"title":"Advanced Features","routes":[{"title":"Preview Mode","path":"/docs/advanced-features/preview-mode.md"},{"title":"Dynamic Import","path":"/docs/advanced-features/dynamic-import.md"},{"title":"Automatic Static Optimization","path":"/docs/advanced-features/automatic-static-optimization.md"},{"title":"Static HTML Export","path":"/docs/advanced-features/static-html-export.md"},{"title":"Absolute Imports and Module Path Aliases","path":"/docs/advanced-features/module-path-aliases.md"},{"title":"AMP Support","routes":[{"title":"Introduction","path":"/docs/advanced-features/amp-support/introduction.md"},{"title":"Adding AMP Components","path":"/docs/advanced-features/amp-support/adding-amp-components.md"},{"title":"AMP Validation","path":"/docs/advanced-features/amp-support/amp-validation.md"},{"title":"AMP in Static HTML export","path":"/docs/advanced-features/amp-support/amp-in-static-html-export.md"},{"title":"TypeScript","path":"/docs/advanced-features/amp-support/typescript.md"}]},{"title":"Customizing Babel Config","path":"/docs/advanced-features/customizing-babel-config.md"},{"title":"Customizing PostCSS Config","path":"/docs/advanced-features/customizing-postcss-config.md"},{"title":"Custom Server","path":"/docs/advanced-features/custom-server.md"},{"title":"Custom `App`","path":"/docs/advanced-features/custom-app.md"},{"title":"Custom `Document`","path":"/docs/advanced-features/custom-document.md"},{"title":"Custom Error Page","path":"/docs/advanced-features/custom-error-page.md"},{"title":"`src` Directory","path":"/docs/advanced-features/src-directory.md"},{"title":"Multi Zones","path":"/docs/advanced-features/multi-zones.md"},{"title":"Measuring performance","path":"/docs/advanced-features/measuring-performance.md"}]},{"title":"Upgrade Guide","path":"/docs/upgrading.md"},{"title":"FAQ","path":"/docs/faq.md"}]},{"title":"API Reference","heading":true,"routes":[{"title":"CLI","path":"/docs/api-reference/cli.md"},{"title":"next/router","path":"/docs/api-reference/next/router.md"},{"title":"next/link","path":"/docs/api-reference/next/link.md"},{"title":"next/head","path":"/docs/api-reference/next/head.md"},{"title":"next/amp","path":"/docs/api-reference/next/amp.md"},{"title":"Data Fetching","routes":[{"title":"getInitialProps","path":"/docs/api-reference/data-fetching/getInitialProps.md"}]},{"title":"next.config.js","routes":[{"title":"Introduction","path":"/docs/api-reference/next.config.js/introduction.md"},{"title":"Environment Variables","path":"/docs/api-reference/next.config.js/environment-variables.md"},{"title":"Custom Page Extensions","path":"/docs/api-reference/next.config.js/custom-page-extensions.md"},{"title":"CDN Support with Asset Prefix","path":"/docs/api-reference/next.config.js/cdn-support-with-asset-prefix.md"},{"title":"Build Target","path":"/docs/api-reference/next.config.js/build-target.md"},{"title":"Custom Webpack Config","path":"/docs/api-reference/next.config.js/custom-webpack-config.md"},{"title":"Compression","path":"/docs/api-reference/next.config.js/compression.md"},{"title":"Static Optimization Indicator","path":"/docs/api-reference/next.config.js/static-optimization-indicator.md"},{"title":"Runtime Configuration","path":"/docs/api-reference/next.config.js/runtime-configuration.md"},{"title":"Disabling x-powered-by","path":"/docs/api-reference/next.config.js/disabling-x-powered-by.md"},{"title":"Disabling ETag Generation","path":"/docs/api-reference/next.config.js/disabling-etag-generation.md"},{"title":"Setting a custom build directory","path":"/docs/api-reference/next.config.js/setting-a-custom-build-directory.md"},{"title":"Configuring the Build ID","path":"/docs/api-reference/next.config.js/configuring-the-build-id.md"},{"title":"Configuring onDemandEntries","path":"/docs/api-reference/next.config.js/configuring-onDemandEntries.md"},{"title":"Ignoring TypeScript Errors","path":"/docs/api-reference/next.config.js/ignoring-typescript-errors.md"},{"title":"exportPathMap","path":"/docs/api-reference/next.config.js/exportPathMap.md"}]}]}],"data":{"description":"Add client and server runtime configuration to your Next.js app."},"route":{"title":"Runtime Configuration","path":"/docs/api-reference/next.config.js/runtime-configuration.md"},"html":"

Runtime Configuration

\n
\n

Generally you'll want to use build-time environment variables to provide your configuration. The reason for this is that runtime configuration adds rendering / initialization overhead and is incompatible with Automatic Static Optimization.

\n
\n
\n

Runtime configuration is not available when using the serverless target.

\n
\n

To add runtime configuration to your app open next.config.js and add the publicRuntimeConfig and serverRuntimeConfig configs:

\n
module.exports = {\n  serverRuntimeConfig: {\n    // Will only be available on the server side\n    mySecret: 'secret',\n    secondSecret: process.env.SECOND_SECRET, // Pass through env variables\n  },\n  publicRuntimeConfig: {\n    // Will be available on both server and client\n    staticFolder: '/static',\n  },\n}\n
\n

Place any server-only runtime config under serverRuntimeConfig.

\n

Anything accessible to both client and server-side code should be under publicRuntimeConfig.

\n
\n

A page that relies on publicRuntimeConfig must use getInitialProps to opt-out of Automatic Static Optimization. Runtime configuration won't be available to any page (or component in a page) without getInitialProps.

\n
\n

To get access to the runtime configs in your app use next/config, like so:

\n
import getConfig from 'next/config'\n\n// Only holds serverRuntimeConfig and publicRuntimeConfig\nconst { serverRuntimeConfig, publicRuntimeConfig } = getConfig()\n// Will only be available on the server-side\nconsole.log(serverRuntimeConfig.mySecret)\n// Will be available on both server-side and client-side\nconsole.log(publicRuntimeConfig.staticFolder)\n\nfunction MyImage() {\n  return (\n    <div>\n      <img src={`${publicRuntimeConfig.staticFolder}/logo.png`} alt=\"logo\" />\n    </div>\n  )\n}\n\nexport default MyImage\n
\n

Related\n \n \n \n \n

\n
\n

Introduction to next.config.js

Learn more about the configuration file used by Next.js.\n
\n
\n

Environment Variables

Access environment variables in your Next.js application at build time.\n
"},"__N_SSG":true}