svelte
Cybernetically enhanced web apps
About
Cybernetically enhanced web apps
Live mirror of the GitHub README. Updated whenever the repo's default branch changes.
What is Svelte?
Svelte is a new way to build web applications. It's a compiler that takes your declarative components and converts them into efficient JavaScript that surgically updates the DOM.
Learn more at the Svelte website, or stop by the Discord chatroom.
Supporting Svelte
Svelte is an MIT-licensed open source project with its ongoing development made possible entirely by fantastic volunteers. If you'd like to support their efforts, please consider:
Funds donated via Open Collective will be used for compensating expenses related to Svelte's development such as hosting costs. If sufficient donations are received, funds may also be used to support Svelte's development more directly.
Roadmap
You may view our roadmap if you'd like to see what we're currently working on.
Contributing
Please see the Contributing Guide and the svelte package for information on contributing to Svelte.
Is svelte.dev down?
Probably not, but it's possible. If you can't seem to access any .dev sites, check out this SuperUser question and answer.
License
Quick facts
npm install svelteThis package powers Svelte
The svelte package is the canonical implementation of Svelte. Sourcemap Explorer uses this exact npm package as the framework-level fingerprint when it flags Svelte on a page — both via the bundled node_modules/svelte/ source paths and via the embedded package.json inside the JavaScript sourcemap.
How Sourcemap Explorer detects svelte
We catch svelte from two complementary signals: bundled source paths and the embedded package.json. Modern bundlers (webpack, Vite, esbuild, Rollup, Turbopack) preserve the original node_modules/svelte/ 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/svelte/` — every match confirms the package is bundled. The matching `sourcesContent[i]` for `node_modules/svelte/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/svelte/package.json")) | $m.sourcesContent[.key] | fromjson | .version' bundle.js.map`. Sourcemap Explorer automates the same query in the popup.
Recent versions
FAQ
What is svelte used for?
Cybernetically enhanced web apps
How can I tell if a website is using svelte?
Open the page in Chrome with the Sourcemap Explorer extension installed and read the Stack tab. We catch `svelte` from two complementary signals: `node_modules/svelte/` 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 svelte?
5.55.5, 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.
What is the relationship between svelte and Svelte?
svelte is the canonical npm package for Svelte. Sourcemap Explorer treats finding `svelte` in a bundle as the framework-level signal that Svelte is on the page, and the page you're reading is the canonical Sourcemap Explorer entry for the package itself.
Where can I read more?
Project homepage: https://svelte.dev. Source code: https://github.com/sveltejs/svelte. Published on npm: https://www.npmjs.com/package/svelte. Licensed as MIT.
Keep reading on Sourcemap Explorer
Practical guides
Detection deep dives
Alternative tools
Detected by Sourcemap Explorer
When a bundle ships sourcemaps, we read the embedded package.json for svelte and report the precise version. Without sourcemaps, an import / require in the page's scripts is enough to flag it.