# Castdeck > Castdeck is a desktop app for YouTube/Twitch/Kick and other live streams. Third parties build "templates": self-contained web pages shown as OBS Browser Sources that react to comments and gifts via the CastdeckSDK. ## Developer docs - [Quickstart](https://castdeck.studio/developers/quickstart): minimal template in 5 minutes. - [SDK Reference](https://castdeck.studio/developers/sdk): CastdeckSDK API and ProjectedEvent fields. - [Build with AI](https://castdeck.studio/developers/ai): a copy-paste context pack for AI assistants. - [llms-full.txt](https://castdeck.studio/llms-full.txt): the full spec in one file. ## Schemas - [template-manifest.schema.json](https://castdeck.studio/developers/schemas/template-manifest.schema.json) - [projected-event.schema.json](https://castdeck.studio/developers/schemas/projected-event.schema.json)