---
title: WebAssembly
description: Load Pixer and process image bytes in browser applications.
---

Browser builds use the same Dart API backed by `pixer.wasm`.

## Add the module

Download `pixer.wasm` from the GitHub release matching your Pixer package
version and place it in the application's web root.

Initialize Pixer before loading an image:

```dart
await Pixer.initialize();

final image = Pixer.fromMemory(bytes);
try {
  final output = image
      .batch()
      .resize(800, 600)
      .encode(const PixerWebPEncoder());
} finally {
  image.dispose();
}
```

By default, Pixer fetches `pixer.wasm` relative to the page. You can supply a
different URL or provide the module bytes directly:

```dart
await Pixer.initialize(wasmUri: Uri.parse('/assets/pixer.wasm'));

// Or:
await Pixer.initialize(wasmBytes: wasmBytes);
```

## Browser API limits

Use `fromMemory` and `encode` on the web. `fromFile`, `saveToFile`, and batch
`saveToFile` throw `UnsupportedError` because browsers do not expose native file
paths.

Pixer supports both JavaScript-compiled and Dart/Flutter Wasm builds.