Cactus + PowerSync Expo Demo

Disclaimer: much of this code was generated using LLMs, however some basic QA was performed by a human.

Known issues: RAG and attachment uploads don't currently work, but completions and STT do work.

Tech demo app for:

• React Native (Expo)
• Supabase Auth + Storage
• Cactus on-device inference (LLM + STT)
• PowerSync React Native SDK
• PowerSync Attachments

Implemented demo sections

• Home: sync status and cumulative cost-savings estimates.
• Transcription: on-device STT with run metrics stored in PowerSync.
• RAG: local document corpus, on-device embeddings/retrieval, local answer generation.
• Attachments: PowerSync attachment queue + Supabase Storage bucket files.
• Offline: forced offline mode, queued local writes, pending CRUD count.

Setup

1. Ensure .env.local contains:

   • POWERSYNC_URL
   • SUPABASE_URL
   • SUPABASE_ANON_KEY
   • CACTUS_API_KEY (optional)

2. Apply Supabase schema:

   • Run supabase/schema.sql.

3. Install dependencies:

pnpm install

4. Start Expo:

pnpm start

For native modules (cactus-react-native, @journeyapps/react-native-quick-sqlite), use a dev build (expo run:ios / expo run:android) rather than Expo Go.

Notes

• PowerSync package dependencies are currently linked from local SDK paths in package.json.
• Cost values are estimated model numbers for demo visualization only.
• Attachment metadata is tracked in demo_files; file blobs are stored in Supabase Storage bucket files.