@expo/metro-runtime
Tools for making advanced Metro bundler features work
About
Tools for making advanced Metro bundler features work
Live mirror of the GitHub README. Updated whenever the repo's default branch changes.
Expo
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Introduction
Expo is an open-source platform for making universal native apps that run on Android, iOS, and the web. It includes a universal runtime and libraries that let you build native apps by writing React and JavaScript.
This repository includes the Expo SDK, Modules API, Go app, CLI, Router, documentation, and various other supporting tools. Expo Application Services (EAS) is a platform of hosted services that are deeply integrated with Expo open source tools. EAS helps you build, ship, and iterate on your app as an individual or a team.
Read the Expo Community Guidelines before interacting in the repository. Thank you for helping keep the Expo community open and welcoming!
Table of contents
📚 Documentation
Learn about building and deploying universal apps in our official docs!
🗺 Project Layout
packagesAll the source code for Expo modules, if you want to edit a library or just see how it works this is where you'll find it.appsThis is where you can find Expo projects which are linked to the development modules. You'll do most of your testing in here.apps/expo-goThis is where you can find the source code for Expo Go.apps/expo-go/ios/Exponent.xcworkspaceis the Xcode workspace. When developing iOS, always open this instead ofExponent.xcodeprojbecause the workspace also loads the CocoaPods dependencies.docsThe source code for https://docs.expo.devtemplatesThe template projects you get when you runnpx create-expo-appreact-native-labThis is our fork ofreact-nativeused to build Expo Go.guidesIn-depth tutorials for advanced topics like contributing to the client.toolscontain build and configuration tools.template-filescontains templates for files that require private keys. They are populated using the keys intemplate-files/keys.json.template-files/ios/dependencies.jsonspecifies the CocoaPods dependencies of the app.
🏅 Badges
Let everyone know your app can be run instantly in the Expo Go app!
[](https://expo.dev/client)
[](https://expo.dev/client)
👏 Contributing
If you like Expo and want to help make it better then check out our contributing guide! Check out the CLI package to work on the Expo CLI.
❓ FAQ
If you have questions about Expo and want answers, then check out our Frequently Asked Questions!
If you still have questions you can ask them on our Discord and Forums or X @expo.
💙 The Team
Curious about who makes Expo? Here are our team members!
License
The Expo source code is made available under the MIT license. Some of the dependencies are licensed differently, with the BSD license, for example.
Quick facts
npm install @expo/metro-runtimeCommon pairings
Packages this one expects to find in the same project. Each is also a Sourcemap Explorer detection target.
How Sourcemap Explorer detects @expo/metro-runtime
We catch @expo/metro-runtime from two complementary signals: bundled source paths and the embedded package.json. Modern bundlers (webpack, Vite, esbuild, Rollup, Turbopack) preserve the original node_modules/@expo/metro-runtime/ paths inside the JavaScript sourcemap's sources[] array — that's the canonical signal. When the matching package.json is also captured in sourcesContent[], we read the exact version field — patch number included. No regex guessing, no version inference.
- 1
Confirm the site exposes sourcemaps
In DevTools Network, check the response headers of any application script for `SourceMap` or `X-SourceMap`. Failing that, fetch the script's last 4 KB and look for a `//# sourceMappingURL=` comment.
- 2
Find the package in the bundle
Open DevTools → Network → reload. Click any application script and look at its sourcemap. Inside, search `sources[]` for entries matching `node_modules/@expo/metro-runtime/` — every match confirms the package is bundled. The matching `sourcesContent[i]` for `node_modules/@expo/metro-runtime/package.json` gives you the exact installed version.
- 3
Read the version directly from package.json
Run `jq -r '. as $m | $m.sources | to_entries[] | select(.value | endswith("node_modules/@expo/metro-runtime/package.json")) | $m.sourcesContent[.key] | fromjson | .version' bundle.js.map`. Sourcemap Explorer automates the same query in the popup.
Recent versions
FAQ
What is @expo/metro-runtime used for?
Tools for making advanced Metro bundler features work
How can I tell if a website is using @expo/metro-runtime?
Open the page in Chrome with the Sourcemap Explorer extension installed and read the Stack tab. We catch `@expo/metro-runtime` from two complementary signals: `node_modules/@expo/metro-runtime/` paths inside the JavaScript sourcemap, and the embedded `package.json` we read for exact-version detection. Without the extension you can do the same lookup manually in DevTools — the steps are listed in the "How Sourcemap Explorer detects" section above.
What is the latest version of @expo/metro-runtime?
55.0.11, as published on the npm registry. The "Recent versions" table on this page lists the most recent 8 releases with their release dates. Sourcemap Explorer reports the version actually bundled into a site, which can lag the latest release by months on real-world deployments.
Where can I read more?
Project homepage: https://github.com/expo/expo/tree/main/packages/@expo/metro-runtime. Source code: https://github.com/expo/expo. Published on npm: https://www.npmjs.com/package/@expo/metro-runtime. Licensed as MIT.
Detected by Sourcemap Explorer
When a bundle ships sourcemaps, we read the embedded package.json for @expo/metro-runtime and report the precise version. Without sourcemaps, an import / require in the page's scripts is enough to flag it.