Pay-per-answer for agents · HashKey Chain

Your agent pays per answer.
Never twice. Refunded if it fails.

A trading agent needs a wallet's risk profile before it trades. It pays a stranger per call, from its own wallet. HSK Meter makes that safe: one payment buys one answer, a retry never pays twice, and a failed delivery is refunded on-chain.

Try it yourself
  • …paid requests on mainnet
  • …refunded on-chain
  • …payments through HashKey HSP

Reading the contract on HashKey Chain…

Live agent console

Meet Tern. It is about to make a trade.

Every step below is a real call made from your browser, right now: to the seller's public endpoint and to HashKey Chain mainnet. The one thing this page never does is pay: that step shows Tern's real past payment, read from the chain. Tern is our open-source buyer agent with its own mainnet wallet, playing a trading bot.

Tern

Trading bot · buyer

Nowidle

Goal: trade with 0x78C8…7F8c, but only after it has paid for that address's risk profile.

Max per call
1¢
Session cap
0¢ of 20¢
  • Pays only USDC.e on chain 177, to this contract
  • Signs nothing above its limit
  • Checks the receipt on-chain before it trusts data

Wallet 0x5270…A361

    Profile API

    Address risk profiles · seller

    Nowonline?

    Sells one answer per payment. A stranger to Tern: they share nothing but the contract.

    Price per call
    …
    Earned, USDC.e
    …
    • Serves each paid request once
    • Can't deliver? Refunds on-chain
    • Holds no key that moves money

    Paid to 0xA8A4…a48D

    Try it yourself

    Ask for a price. Set a limit. Check a receipt.

    No wallet, no money: these are free calls to the same public endpoint.

    1 · Get a real quote

    Profile any HashKey Chain address. Your browser makes up a throwaway payer; the quote is bound to it.

    2 · Check a receipt

    Paste a transaction hash or requestId. The verifier reads the contract and answers ACCEPT or REJECT.

    Want to tamper with a quote and watch it refused? Four attacks on the try page.

    HashKey HSP

    Agents paying agents through HashKey's own payment server

    Loading the receipts…

    1. 402Receiving agent prices the call and signs its conditions
    2. CheckPayment agent checks price, token, chain and recipient
    3. SignWallet signs; HSP's gateway broadcasts, so the payer needs no gas
    4. SafeHSP reports payment-safe, attributed to our team
    5. Serve onceSeller checks HSP and the chain, serves once, refuses a replay

    HSP's QA environment with test tokens on public testnets. Status and attribution are what HSP's query_payment answered; "Check on-chain" reads the transaction from a public testnet node, in your browser. These payments did not go through the mainnet contract.

    For sellers

    Put a price on any API call

    Live from the contract: what the Profile API seller has earned, call by call.

    Address profile

    …

    per call

    Transaction check

    …

    per call

    Earned, net of refunds

    …

    USDC.e

    Refund rate

    …

     

    Register an endpoint, then sell itfrom the README
    # 1. price a path on the contract (30000 = 0.03 USDC.e)
cast send $METER "registerEndpoint(uint128,address,string)" \
  30000 $PAYEE "GET /v1/your/path" --rpc-url $RPC --account provider

# 2. map the path to its endpoint id (RESOURCES in server/seller.py), run it
python3 server/seller.py --key-dir /path/to/keys --port 8402

# 3. any agent buys, inside its own limits
python3 agent/buyer.py "http://localhost:8402/v1/your/path" \
  --max-price 0.05 --session-cap 0.20

    Proof and limits

    What is real here, and what is not done yet

    Mainnet Our own settlement rail

    The contract HskPayPerRequest is verified on HashKey Chain mainnet and settles real USDC.e. It has no admin, no fees and no upgrades. Payments can be gasless (the buyer signs an EIP-3009 authorization).

    Reading the newest payment…

    Contract on the explorer · Live dashboard

    Testnets HashKey's HSP server

    The HSP payments are made through HashKey's official HSP Agentic Payment server in its QA environment, with test tokens on public testnets. They are real HSP payments, attributed to our team, but not real money.

    All HSP receipts · raw file

    Not yet Honest limits

    • The volume is ours: test buyers and our own agents, not paying customers yet.
    • The public endpoint holds no key, so it can't submit gasless payments or send refunds itself; our seller server does both.
    • HSP runs on testnets only; the mainnet contract and HSP are separate rails today.
    • Tern's trading rule on this page is a demo rule; its profile answer is real.

    Source code · Receipt verifier · Explorer · x402 terms