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FOR THE PEOPLE BUILDING AGENTS

Give your agent an expense account.

An allowlist plus per-call and per-day budgets, enforced before any x402 payment is signed. A receipt for every decision — settlements and refusals alike. Your agent pays for what it uses and can't spend what you didn't approve.

Mint a keyRead the quickstart
SPEND CONTROL

Budgets your agent can't exceed

Allowlist + per-call and per-day caps, checked before any payment is signed. Runaway loops and injected tool calls hit the wall, not your wallet.

RECEIPTS EVERYWHERE

Every decision, ledgered

Settlements and refusals land in your dashboard — charts, budgets, and Basescan links per call. Headless agents sync via API key.

SIGNED GRANTS

Terms your wallet attested

EIP-712-sign your grant so the authorization is portable — the precursor to on-chain spend permissions. Change the terms, re-sign, done.

Quickstart

  1. 01 Install the SDK: npm install yeetful
  2. 02 Mint a key on your keys page and approve the agents you trust under approvals. The secret shows once — that's the point.
  3. 03Wrap your agent's fetch:
import { yeetful } from 'yeetful/agent'

const pay = yeetful({
  wallet, // a viem WalletClient (small funded burner)
  grant: {
    id: 'your-grant-id', // from yeetful.com/dashboard
    allow: ['tripadvisor.x402.paysponge.com'],
    perCallUsd: 0.05,
    perDayUsd: 5,
  },
  apiKey: process.env.YEETFUL_API_KEY, // yf_… — receipts sync to your dashboard
})

// 402 challenge → grant check → USDC payment signed → 200 + receipt
const res = await pay(
  'https://tripadvisor.x402.paysponge.com/api/v1/location/search?searchQuery=tokyo',
)

throws GrantError('NOT_ALLOWED' | 'OVER_PER_CALL' | 'BUDGET_EXCEEDED' | 'EXPIRED' | 'REVOKED') — denied before any network I/O.

Grants API

Bearer or session auth

Every route accepts your browser session (SIWE) or Authorization: Bearer yf_… — the key you minted. Keys authenticate as your wallet; grants stay owner-scoped either way.

  • GET/api/grants

    List your grants with spend totals

  • POST/api/grants

    Create a grant (allowlist + caps + expiry)

  • GET/api/grants/:id

    One grant + recent ledger + budget status

  • PATCH/api/grants/:id

    Adjust caps/label, revoke or reactivate

  • DELETE/api/grants/:id

    Delete a grant (ledger cascades)

  • GET/api/grants/:id/signature

    EIP-712 payload to wallet-sign the terms

  • PUT/api/grants/:id/signature

    Attach the signature (server-verified)

  • POST/api/grants/:id/ledger

    Sync a receipt into the hosted ledger

Receipt sync

POST /api/grants/:id/ledger

The SDK's onReceipt seam posts here automatically when you pass apiKey. Body fields, if you'd rather wire it yourself:

  • hoststring

    Hostname or full URL of the paid endpoint (required)

  • amountUsdnumber

    USD settled — 0 for denials (required)

  • okboolean

    true = settled, false = denied/failed (default true)

  • txHashstring

    Base settlement transaction, when settled

  • serviceNamestring

    Display name for the dashboard charts

  • notestring

    "settled", a violation code, or your own marker

The rest of the stack

yeetful on npm x402 client/server helpers + the agent wrapperexample-agent the whole integration in ~40 lines — free demo modetravel-agent demo a full agent that researches a trip and pays its own way