The Steamworks for WebView2 plugin allows integrating a project with Steam. It is currently only supported with the Windows WebView2 export option in Construct 3 r359+.
The plugin provides basic access to the user details, the Steam Overlay and achievements.
Exporting for Steam
To test your game with Steam, export it with the Windows WebView2 option. You must also have Steam installed and running on your system for the plugin features to work. Use the Is available condition to check if the plugin features are available.
During development, you must also set your Steam App ID in the plugin's App ID property, and check Development mode. This tells Steam your app ID. If Steam cannot determine the App ID it will fail to initialize and Is available will be false, so this is necessary during development to make sure Steam knows the app ID and enable Steam features. If you don't have an app ID yet, you can use the app ID 480, which is the ID for the Steamworks SDK sample "Space war".
Before publishing to Steam, be sure to uncheck Development mode, as when it is on it disables Steam's recommended "restart app if necessary" behavior.
Steam Overlay
When the Enable overlay property is checked, the Steam Overlay is enabled using a workaround, and can only be shown with an opaque background. This is because technical limitations in the Steam Overlay mean it cannot normally be shown over WebView2. There are more details about the technical issues involved in the blog post Trying to show the Steam Overlay over WebView2. If you want better Steam Overlay support, you'll need to contact Valve and ask them to fix the Steam Overlay - we've done the best we can given its limitations.
If you uncheck Enable overlay, the Steam Overlay won't show in-game, but in this case Steam reverts to fallbacks. For example the achievement unlocked notification is shown using a different kind of overlay, and attempts to open the overlay will normally switch focus to the Steam application. In some cases this may be an acceptable alternative to showing the overlay.