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Architecture Overview

System Components​

Architecture

Components​

Frontend (x402-zama-example)​

Next.js application providing:

  • Wallet connection (RainbowKit)
  • ERC7984 token operations
  • x402 payment flow
  • Balance encryption/decryption

Facilitator (x402-facilitator)​

Hono-based API service for:

  • Payment verification
  • On-chain event extraction
  • Server-side FHE decryption
  • Amount validation

fhevm-sdk​

React SDK providing:

  • FHE encryption hooks
  • Decryption signature management
  • FHEVM instance management
  • Storage utilities

FHE Relayer​

External service for:

  • FHE key distribution
  • Server-side decryption
  • Gateway operations

Data Flow​

  1. Encryption: Client encrypts amounts using fhevm-sdk
  2. Transfer: Encrypted transfer submitted to blockchain
  3. Verification: Facilitator extracts handle from chain
  4. Decryption: FHE relayer decrypts with user authorization
  5. Validation: Facilitator confirms payment meets requirements