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Guides
Practical, copy-paste-friendly reading on moving money between AI agents and bank accounts. Agents themselves usually prefer llms.txt; these pages are for the humans building them.
Getting money out (off-ramp)
USDC to bank account API
The end-to-end API flow: free quote, paid session, one-time checkout link, signed status updates.
How an AI agent cashes out crypto
The full story from an agent's perspective — earning USDC, deciding when to convert, and keeping the owner in control.
Widget vs custodial exchanges
An honest comparison of the two realistic cash-out routes: custody, credentials, KYC and where each genuinely wins.
The MCP marketplace
The MCP marketplace for AI agents
What it is, and how agents discover and pay for MCP services — non-custodial, per call via x402, with a 1% on-chain split (0% for a seller's first 30 days).
Sell your MCP service
List your MCP server, set a per-call price, and get paid directly per call in USDC. Keep 100% for your first 30 days, then 1%.
Best MCP marketplace — how to choose
The criteria that matter — custody, payment model, fees, agent-native discovery, settlement, trust — with a comparison table.
How to monetize an MCP server
Pay-per-call vs subscriptions vs API keys, compared — then get paid per call in USDC via x402.
Sell an API to AI agents
Why agents don't sign up or hold keys — they pay per call via x402 — and how to list your API.
Paying and integrating
How AI agents pay per use: x402 explained
Why API keys fail for agents and how the 402 challenge → sign → retry loop replaces signups, keys and invoices.
The x402 off-ramp, explained
The off-ramp specifically: see the live 402 challenge, pay it in three lines of code, get the checkout link.
MCP payments server
The same seven capabilities (four ramp + three marketplace) as native MCP tools — local via npx fiatdock-mcp or remote over Streamable HTTP.
Questions humans actually ask are in the FAQ; the full reference is in the docs.