Architecture

End-to-end flow

1. Browser (Next.js) — User opens /started (or similar), connects wallet.
2. POST /getAmount — Facilitator returns ciphertext for the demo price.
3. Sign message — Client builds payload (ciphertext, amount, recipient, nonce, …) and calls signMessage.
4. POST /verify — Facilitator checks Ed25519 signature and x402-style payload.
5. Simulation / handles — Client may simulate IncoToken transfer to obtain handles (see app code).
6. POST /settle (step 1) — Facilitator returns requiresPayerSignature: true and unsignedTransaction (base64).
7. Sign transaction — User signs once; client serializes with requireAllSignatures: false / verifySignatures: false (fee payer not signed yet).
8. POST /settle (step 2) — Client sends signed tx; facilitator calls Kora signAndSendTransaction.
9. Kora — Adds fee-payer signature, submits to Solana; client shows Solscan link.

Components

| Layer | Role | |-------|------| | Next.js app | UI, wallet adapter, calls facilitator + builds/signed txs | | Facilitator (Express) | Ciphertext, verify, build unsigned tx, proxy to Kora | | Kora | Fee payer RPC, partially signed tx handling | | IncoToken (Anchor) | transfer_with_authorization, Ed25519 relative index | | Inco Lightning | Confidential SPL / FHE CPIs from IncoToken |

Devnet program IDs (reference)

Use these in Kora allowed_programs (or equivalent):

• ComputeBudget111111111111111111111111111111 — Compute Budget
• 9Cir3JKBcQ1mzasrQNKWMiGVZvYu3dxvfkGeQ6mohWWi — IncoToken
• 5sjEbPiqgZrYwR31ahR6Uk9wf5awoX61YGg7jExQSwaj — Inco Lightning
• Ed25519SigVerify111111111111111111111111111 — Ed25519 verify

See my-app/README.md in the repo for the full table and troubleshooting.