Ephemeris is an event attendance system built around the idea that showing up should mean something. Organizers create events and display a QR code at the door. Attendees scan it, get a session-scoped identity, mark their attendance, and can mint a Solana NFT as a permanent, verifiable record of being there.
There are no accounts. No passwords. Your identity exists only for the duration of the event.
For organizers:
- Create an event with a name, date, time, location, and optional NFT support
- Get a QR code that attendees scan to enter
- Optionally enable NFT minting so attendees can take something on-chain with them
For attendees:
- Scan the QR code to receive a time-limited JWT tied to the event
- Mark attendance once — it is recorded and cannot be re-submitted
- Issue a receipt describing your experience
- Mint a Solana NFT for your receipt if the organizer has enabled it
- View and share cryptographic proofs of attendance or receipts — verifiable by anyone, no token required
| Layer | Tech |
|---|---|
| Mobile app | React Native + Expo (file-based routing via Expo Router) |
| Styling | NativeWind (Tailwind for React Native) |
| Backend | Hono on Node.js + TypeScript |
| Database | PostgreSQL via Prisma ORM |
| Blockchain | Solana — NFT minting via on-chain collection |
| Wallet | Solana Mobile Wallet Adapter (Android) |
monolith-hackathon/
client/ React Native app (Expo)
server/ Hono API server
cd server
npm install
npm run devThe server runs on port 8080 by default. It expects a DATABASE_URL environment variable pointing to a PostgreSQL instance.
npx prisma migrate devcd client
npm install
npx expo startScan the QR code with Expo Go, or run on an Android/iOS emulator.
All routes are under /api. Authenticated routes require Authorization: Bearer <token> where the token is issued by POST /identity/issue/:eventId after scanning an event QR code.
| Route | Auth | Purpose |
|---|---|---|
POST /identity/issue/:eventId |
No | Issue identity + JWT after QR scan |
GET /identity/status |
Yes | Check identity status and attendance |
POST /attendance/mark |
Yes | Mark attendance (one-time) |
POST /events/create |
No | Create a new event |
GET /events/:eventId/qr |
No | Get the QR entry URL for an event |
GET /receipts |
Yes | List receipts for current identity |
POST /receipts/issue |
Yes | Issue a new receipt |
POST /receipts/:id/mint-nft |
Yes | Mint NFT for a receipt |
GET /proofs |
Yes | List all proofs (attendance + receipts) |
POST /proofs/verify |
No | Verify any proof by ID — public |
There are no user accounts. When an attendee scans an event QR code, the server issues a JWT that is scoped entirely to that event session. The token expires, attendance can only be marked once, and everything — receipts, proofs, NFTs — is tied to that single identity. This keeps the system lightweight while still giving attendees something meaningful and verifiable at the end.
If an organizer enables NFT support when creating an event, a Solana NFT collection is created for that event. Attendees who connect a Solana wallet (via Mobile Wallet Adapter on Android) can mint an NFT linked to their receipt. The mint address and metadata URI are stored on the receipt record so the proof is always traceable back to the on-chain asset.
S1 - Events
Displays all available events. Organizers can create new events, attendees can browse and scan QR codes to join.
S2 - QR Scanner
Attendees scan the QR code at the event door to receive their session-scoped identity and JWT token.
S3 - Attendance
Mark your attendance for the current event. This is a one-time action that records your presence permanently.
S4 - Receipts & Minting
View your receipts and mint Solana NFTs for your attendance. Each NFT is a verifiable on-chain proof that you attended the event.
S5 - Minted NFT in Phantom Wallet
The final proof of attendance — your minted NFT displayed in the Phantom Solana wallet, verifiable by anyone on the blockchain.