---
updatedAt: 2025-06-16T21:13:42.000Z
agentTools:
  projectIndex: https://docs.ultralig.ht/llms.txt
---

# Using the C API

In addition to our [C++ API](https://docs.ultralig.ht/docs/using-the-cpp-api), Ultralight offers a portable C API for use within C and other languages.

## Set Up Include Directories

To use Ultralight in your C code, add the following path to your project's include directories (replace `<SDK_ROOT>` with the path to the Ultralight SDK):

```
<SDK_ROOT>/include/
```

## Include Headers In Your Code

Simply include `<Ultralight/CAPI.h>` at the top of your code to import the API.

```
#include <Ultralight/CAPI.h>
```

If you want to use the optional AppCore API (cross-platform windowing/drawing layer), you should also include `<AppCore/CAPI.h>` at the top of your code.

```
#include <AppCore/CAPI.h>
```

Ultralight also exposes the full **JavaScriptCore** API so that users can make native calls to/from the JavaScript VM. To include these headers simply add:

```
#include <JavaScriptCore/JavaScriptCore.h>
```