Discover x402-gated APIs you can pay for — browse the facilitator's Bazaar catalogue of registered x402 resources, each with the price and payment terms it accepts. Use this BEFORE x402_pay whenever you need to FIND a paid endpoint rather than call one you were already given: the pay tool only fetches a URL you hand it, so this is the only way to locate a monetized API on your own. Returns { resources: [{ resource, type, x402Version, accepts: [{ scheme, network, amount, asset, payTo }], lastUpdated, metadata? }], pagination: { limit, offset, total } } — amount is in ATOMIC units (USDC 6-decimals: "10000" = $0.01), so convert before quoting a price to the user. PUBLIC: needs no API key, no wallet and spends nothing, so it is always safe to call. Filter with type (e.g. "http") and page with limit/offset. Then pass a chosen resource URL to x402_pay to actually buy it.

Fetch an HTTP resource and, if it returns 402 Payment Required, pay it automatically with x402 and return the paid response. On a 402 it: parses the merchant's price, authorizes via the CryptoAPIs buyer /authorize, signs the payment LOCALLY (non-custodial — the key never leaves this process), and retries with the X-PAYMENT header. Returns { status, paid, body, settlement? }. This is for HTTP URLs — to pay a paid MCP TOOL on another server, use x402_pay_tool instead. Supported today: EVM (eip712, e.g. Base USDC) and Solana. Tron, UTXO (bitcoin/ltc/doge/dash/bch/zcash), Kaspa and XRP are UPCOMING — wired but not yet enabled, and paying on them returns a clear coming-soon (family_not_yet_supported) result. Set CRYPTOAPIS_API_KEY + X402_WALLET_ID once, plus the signing key(s) for the chain(s) you pay on: X402_PRIVATE_KEY (EVM hex), X402_SVM_SECRET (base58). A scheme with no configured key errors cleanly (never mis-signs). Env vars keep keys OUT of tool-call logs. Use allowedNetworks to restrict chains, maxAmount as a per-call spend cap, and allowedHosts to restrict WHICH SITES may be paid (a url outside the list is refused before any network call; set X402_ALLOWED_HOSTS in the MCP config to pin it outside the model's reach). SECURITY: this tool holds spending keys — use only in trusted local environments, and prefer pinning allowedHosts + maxAmount via env for unattended runs.

Call a TOOL on another MCP server and, if that tool requires payment, pay it automatically with x402 and return the paid result. This is the MCP-transport twin of x402_pay: use x402_pay for an HTTP url, and THIS for a paid tool on another MCP server. On a challenge it reads the PaymentRequired (from structuredContent, falling back to content[0].text), authorizes via the CryptoAPIs buyer /authorize, signs LOCALLY (non-custodial — the key never leaves this process), and retries the tool call once with the payment in _meta["x402/payment"] (a raw object, no base64 — MCP carries structured JSON natively). Returns { paid, result, settlement? }; the settlement receipt comes back in _meta["x402/payment-response"]. The upstream server is launched over stdio for the call and shut down afterwards. Same credentials and keys as x402_pay: CRYPTOAPIS_API_KEY + X402_WALLET_ID, plus X402_PRIVATE_KEY (EVM) / X402_SVM_SECRET (Solana). Supported today: EVM (eip712) and Solana; Tron, UTXO, Kaspa and XRP return a clear coming-soon result. Use allowedNetworks and maxAmount as guardrails. SECURITY: this tool holds spending keys and launches the process you name — use only in trusted local environments.