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Escrow Wallet

The Playground uses a custodial wallet system so users can query HYRE endpoints without manual transaction signing. Deposit USDC once, and the agent spends micro-fees automatically.

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How It Works

1

Wallet provisioned on signup

When a user signs in via Privy, the backend generates a new wallet keypair. The private key is encrypted with AES-256-GCM and stored in Cloudflare D1.
2

User deposits USDC

The user sends USDC to their custodial wallet address. Three chains are supported:
3

Balance tracked in real-time

The backend monitors incoming transfers and updates the user’s balance. The current balance is visible in the Playground sidebar.
4

Auto-deduction per query

When the chat agent calls a HYRE endpoint, the backend deducts the endpoint price from the escrow balance before forwarding the request. No signing popups.
5

Withdraw anytime

Users can withdraw their remaining USDC balance to any external wallet at any time via the Playground settings.

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Encryption

The encryption key is derived from the user’s Privy ID and a server-side secret. The private key cannot be reconstructed without both components.

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Balance Model

The escrow system uses an optimistic balance model:
  1. Check — Before calling a HYRE endpoint, verify the user has sufficient balance.
  2. Deduct — Subtract the endpoint price from the in-memory balance.
  3. Call — Forward the request to the HYRE API with an internal auth header (bypasses x402).
  4. Confirm — On success, persist the deduction. On failure, refund the balance.
This ensures users are never charged for failed requests.

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Supported Chains

  • Gas token: SOL
  • Gas cost: ~$0.0005 per transaction
  • USDC: EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v
  • Settlement: ~400ms
  • Facilitator: Dexter (x402.dexter.cash)
  • Gas token: ETH
  • Gas cost: ~$0.01 per transaction
  • USDC: 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913
  • Settlement: ~2s
  • Facilitator: PayAI (facilitator.payai.network)
  • Gas token: sFUEL (free)
  • Gas cost: Zero
  • USDC: 0x85889c8c714505E0c94b30fcfcF64fE3Ac8FCb20 (bridged)
  • Settlement: ~1s
  • Facilitator: PayAI (facilitator.payai.network)
  • Best for: cost-sensitive agents and high-frequency queries