Private beta channel online
Download CAST v59.
This downloads an Android APK file. After it finishes, open the downloaded file and tap Install.
After it downloads
- Open the file named
cast-v59-private-beta.apk. - If you do not see it, open Chrome menu > Downloads or Files > Downloads.
- Tap Install, then open CAST.
Current buildCAST v0.1.59
Download sizeAbout 55 MB
Model setupAbout 2.6 GB
MemoryLocal first
Install from the APK file
Yes, it is a file. Android downloads CAST as an APK file; open that file, install it, then CAST will handle setup.
- Tap Download Android APK.This saves
cast-v59-private-beta.apkto the phone. - Open the APK file.If Chrome does not show it, use Chrome menu > Downloads or Files > Downloads.
- Allow install if Android asks.This usually says “install unknown apps” for Chrome or Samsung Internet.
- Open CAST.Create/sign into account if available, or continue local-only for testing.
- Download the default model in CAST.Use Wi-Fi. Keep the app open while Gemma 4 E2B downloads.
If nothing opens after download, do not tap the beta page again. Open the downloaded APK from Chrome downloads or the phone's Files app.
Current CAST private beta release
Technical release details for testers who need checksums or Play bundle info.
Loading manifest
Checking release policy
Most people only need the Download button above. This section is for checksum verification and internal testing.
Local-first trust contract
This is the core marketing promise and the engineering constraint. Private beta should prove the promise before public rollout.
Stays local by default
Personal memory, raw private chats, local databases, model paths, tokens, and API keys stay on the user's device unless explicitly exported.
Shared only after review
Bug reports, release checksums, hardware summaries, and lessons can go to the beta hub after redaction and user approval.
Permissions are tool-based
Camera, mic, location, watch, and file access should be requested only when the user taps that tool and understands what will be stored.
Sessions have boundaries
Stella and the phone sidekick can talk inside a user-started room. When the room ends, model-to-model chat stops.