# CDN installation


If your project has no build step and you don't use npm, you can load the Flare client directly from the [jsDelivr](https://www.jsdelivr.com/) CDN. If you use npm with a bundler (Vite, Webpack, …), follow the [regular installation guide](/docs/javascript/getting-started/quick-start) instead.

## Loading via jsDelivr

Add a module script to your page that imports the Flare client from jsDelivr and starts it with your project key:

```html
<script type="module">
    import { flare } from 'https://cdn.jsdelivr.net/npm/@flareapp/js@2/+esm';

    flare.light('PROJECT PUBLIC KEY');
</script>
```

You can find the project key on the project settings page, below the project configuration section.

A few things to note about the URL:

- **`@2`** pins the client to major version 2. You'll automatically get bug fixes and new features, but a future breaking major release won't be pulled in until you bump it yourself. You can also pin an exact version like `@flareapp/js@2.3.0` if you want full reproducibility.
- **`/+esm`** tells jsDelivr to serve the ES module build and rewrite the package's dependencies to browser-loadable CDN ESM URLs. The browser then fetches `@flareapp/core` (and its own dependencies) as a chain of CDN modules, because jsDelivr rewrites the imports rather than bundling everything into one file. This is what makes the client work without a bundler: the raw `@flareapp/js` module on its own contains a bare `@flareapp/core` import that a browser can't resolve.

## Verifying the install

The Flare client assigns itself to `window.flare` as soon as the module is imported. (The `import` binding itself is scoped to your module script, but the SDK sets the `window.flare` global as a side effect of being loaded, so it's available even though you're using ESM.) You can interact with it from the console. Once `flare.light()` has set your project key, run `flare.test()` in your browser console to send a real test error to Flare. It will show up on your project's dashboard.

If something goes wrong, enable debug mode by passing `true` as the second argument to `flare.light('PROJECT PUBLIC KEY', true)`, or by calling `flare.configure({ debug: true })`.

## Why a regular `<script src>` tag won't work

The `@flareapp/js` package only ships CommonJS and ES module builds. There is no UMD or IIFE ("browser global") build. A classic `<script src="...">` tag therefore can't load the client or expose `window.flare` on its own. Always use `<script type="module">` together with the jsDelivr `/+esm` URL shown above.

## Next steps

Once the client is running, you can customize it with [`flare.configure()`](/docs/javascript/reference/configuration), and read about [sourcemaps](/docs/javascript/errors/sourcemaps) if you later move to a build process.