Have you been using our legacy API under the fin.desktop object? Welcome to the new and improved V2 API! You can now access the same classes and methods directly on the fin object. Please read this explanation of the differences between the legacy V1 API and the new V2 API.

Welcome to the JavaScript API. This API allows you to create an HTML/JavaScript application that has access to the native windowing environment, can communicate with other applications and has access to sandboxed system-level features.

The fin namespace

When running within the OpenFin Runtime your web applications have access to the fin namespace and all the modules within the API without the need to include additional source files. You can treat the fin namespace as you would the window, navigator or document objects.

API Methods

The full API Method Index can be found below.

  • To find a specific method by name, simply search this page.
  • To browse the API, click one of the classes or namespaces in the sidebar at left.


New applications and windows are instantiated by the respective start and create calls with the following options objects:

For a single-page reference to all application settings and configuration options, see also our Application Config page.


<!DOCTYPE html>
            #status-indicator {
              display: inline-block;
              height: 10px;
              width: 10px;
              background-color: red;
              border-radius: 20px;
            #status-indicator.online {
              background-color: green;
        <script type="text/javascript">
            fin.System.getVersion().then(version => {
                document.querySelector('#of-version').innerText = version;
            OpenFin version <span id="of-version"></span>

Index of API Methods