> ## Documentation Index
> Fetch the complete documentation index at: https://mintlify.com/LadybirdBrowser/ladybird/llms.txt
> Use this file to discover all available pages before exploring further.

# Utilities overview

> Command-line utilities bundled with Ladybird Browser for testing and development

Ladybird Browser includes several command-line utilities for testing, debugging, and working with web technologies. These tools are primarily intended for developers and testing purposes.

## Available utilities

### JavaScript engine (js)

A standalone JavaScript interpreter with REPL support. Enables interactive JavaScript execution and script testing outside the browser environment.

[Learn more about the JS utility →](/reference/utilities/js)

### WebAssembly runtime (wasm)

A WebAssembly module parser, validator, and executor. Supports both standalone WASM execution and WASI (WebAssembly System Interface) for system interactions.

[Learn more about the WASM utility →](/reference/utilities/wasm)

### XML parser (xml)

Parses and displays XML documents with syntax highlighting. Includes XML validation and test suite support.

[Learn more about the XML utility →](/reference/utilities/xml)

### DNS resolver (dns)

A DNS query tool supporting multiple record types, DoT (DNS over TLS), and DNSSEC validation.

[Learn more about the DNS utility →](/reference/utilities/dns)

### Image converter (image)

Converts and manipulates images between formats (PNG, JPEG, BMP, WebP). Supports color profile management, cropping, and alpha channel operations.

[Learn more about the Image utility →](/reference/utilities/image)

## Building utilities

The utilities are built using CMake as part of the Ladybird build system:

```bash theme={null}
cmake -B build
cmake --build build
```

<Note>
  On Windows, the `js` and `wasm` utilities have limited functionality. LibLine (for REPL features) is not available on Windows.
</Note>

## Installation

Utilities can be installed individually using CPack:

```bash theme={null}
cpack --config build/CPackConfig.cmake -G TGZ -C js
cpack --config build/CPackConfig.cmake -G TGZ -C wasm
```

This creates platform-specific archives containing the utility and commit information.

## Common use cases

### Testing JavaScript implementations

Use the `js` utility to test ECMAScript compliance and run Test262 test suites.

### WebAssembly module validation

Use the `wasm` utility to validate WASM modules before deployment.

### Image format conversion

Use the `image` utility for batch image conversions and optimizations.

### DNS debugging

Use the `dns` utility to troubleshoot DNS resolution issues and validate DNSSEC.

## Source code

All utility source code is located in the `Utilities/` directory:

* `js.cpp` - JavaScript interpreter
* `wasm.cpp` - WebAssembly runtime
* `xml.cpp` - XML parser
* `dns.cpp` - DNS resolver
* `image.cpp` - Image converter
* `test262-runner.cpp` - Test262 test runner