Return the x402 gateway's machine-readable manifest: price, token, network, recipient, payment flow, free-preview and proof-of-purchase capabilities. No payment required.

Fetch the HTTP 402 challenge and return its FREE preview (a sample of the paid dataset) plus the price/invoice, so the agent can decide whether to pay. No payment required.

Pay the quoted USDC on Base and return the unlocked {data, receipt}. Requires env X402_AGENT_PRIVATE_KEY (a Base wallet with >= the quoted USDC + gas). WARNING: this spends real USDC on-chain.

Verify a proof-of-purchase receipt with the gateway (recovers the EIP-191 signer and checks it equals the server's receipt signer). Anyone can call this — no payment required.

Check a prepaid balance: remaining balance, calls_remaining, and next_nonce. Pass an address, or leave blank to use the wallet from X402_AGENT_PRIVATE_KEY.

Credit a prepaid balance from an on-chain USDC deposit to the recipient. First send USDC to the recipient on Base, then call this with the tx_hash.

Fetch the paid data by drawing from the prepaid balance — GASLESS, NO on-chain tx. This is the habitual-use path: after one topup you can call this many times for free (only gas-free balance debit). Requires X402_AGENT_PRIVATE_KEY with a funded balance.