x402 turns HTTP's forgotten 402 Payment Required into a working
payment rail: the server names a price, the client signs a gasless USDC transfer, and the goods
come back in the same response. This suite is the commerce layer built on top of it — booking a
table, holding a flight, shipping a package, splitting a bill across six wallets.
Every paid route returns the thing you bought, in the body of the same response.
You pay POST /book and the 200 is the reservation — id, confirmed time,
refund terms, calendar invite. Nothing is promised for later. Where a use case is inherently
asynchronous, it becomes pay-per-poll (a fresh snapshot plus the delta since your last check) or
returns a signed claim instrument you hold immediately.
GET /availability
└─→ 402 Payment Required { price: "$0.001", asset: USDC, network: base-sepolia, payTo: 0x… }
client signs an EIP-3009 transferWithAuthorization (gasless — no ETH needed)
GET /availability X-PAYMENT: <signed payload>
└─→ 200 OK { slots: [ … ] } X-PAYMENT-RESPONSE: <settlement receipt>Self-hosted servers a business runs itself, so the inventory is real by definition. An open-source Resy, Calendly, and storefront that AI agents can transact with directly.
Open-source Resy: a self-hosted restaurant reservation server that AI agents can book via x402 refundable holds
Self-hosted Calendly with x402: salons, doctors, consultants sell appointment slots directly to agents and humans
Class and session booking server — fitness studios and workshop hosts sell seats per-class via x402
Time-slot rental server for courts, rooms, and equipment — reserve and pay per block with x402
Live waitlist server — pay to join a queue, receive a signed position token, auto-refund if never served
Self-hosted store with x402 checkout — sell digital goods (delivered in-response) and physical goods (signed order confirmation)
Backed by genuine upstream data — keyless APIs are called live out of the box; keyed APIs use free developer tiers and fall back to labeled fixtures so every demo runs without a single paid key.
Pay-per-query flight search over the Amadeus API — offers, live pricing, and fare-drop checks for agents
Pay-per-query hotel search and offer pricing over Amadeus — agents shop rooms without accounts
Transit trip planning and live delay snapshots from open GTFS/GTFS-RT feeds, priced per query
Campground search and availability from the official Recreation.gov RIDB API, per-lookup pricing
Tours and activities search via Amadeus — agents find bookable experiences by location
POI concierge over OpenStreetMap Overpass with optional Yelp enrichment — restaurants, cafes, anything, per query
Event search and on-sale checks over Ticketmaster Discovery — agents find real events and ticket windows
Movie catalog concierge over TMDB — search, details, and recommendations per query
Agents buy clean, chaptered full-text public-domain books — OpenLibrary search, Gutenberg delivery, in-response
Scholarly search over arXiv, Crossref, and Semantic Scholar — papers, citation graphs, formatted bibliographies
Global news query service over GDELT — article sets, timelines, and delta pulses, per query
Crypto prices via CoinGecko and SEC filings via EDGAR — real market data per lookup
Go/no-go weather decisions for plans — forecasts and verdicts from Open-Meteo/NWS, keyless and live
Grid carbon intensity now and best-window scheduling — keyless live data for green agents
Real grocery product search and cart building over the Kroger API, priced per operation
Live marketplace intelligence over eBay Browse — listings search and is-this-a-deal verdicts
Rate shopping and label generation via Shippo/EasyPost test mode — agents ship things, label returned in-response
Agents send physical letters and postcards via Lob's test environment — preview PDF returned in-response
Real message delivery per-message: Telegram bot messages and SMTP email with delivery receipts in-response
Authoritative domain availability and expiry intel via RDAP — keyless, live, per lookup
Fund GitHub issues with x402 — signed bounty certificates, merged-PR verification reports, settlement receipts
Podcast search and episode intel over the Podcast Index API, per query
The plumbing every paid agent service needs: discovery, refundable holds, wallet policy, receipts, approvals, and an MCP bridge into Claude and GPT.
The skill.md toolkit: generate and validate agent-discoverable skill files (the agentres.dev pattern) from OpenAPI specs
Searchable registry of x402-paid agent skills — register with a signed listing, agents search per query
The $0.01 refundable-hold pattern as drop-in Express middleware — charge a hold, auto-refund on failure, ledger included
Wallet policy daemon for agents — budgets, per-merchant caps, approval thresholds, signed policy verdicts
Receipts and accounting for agent spending — enriched on-chain receipt lookups and ledger exports
Framework that turns any website flow into an x402-paid API — declare a flow in YAML, Puppeteer executes, artifact returned in-response
The 'code sent to your email' step, solved for agents — paid relay mailboxes, retrieved OTP codes returned in-response
One-time account linking vault for agent flows — encrypted credential links with scoped, expiring access tokens
Normalize any booking confirmation into a portable record — ICS invite and status snapshots per query
A fake town on testnet — mock restaurant, hotel, and store implementing the suite's exact contracts, for end-to-end agent purchase testing
MCP server that gives Claude/GPT agents commerce tools — each tool call pays an upstream x402 endpoint and returns its artifact
Human-in-the-loop checkout: agent requests approval above its cap, human pays via the drop-in modal, agent fetches the signed outcome
Things that only become possible once machines can pay: splitting a dinner bill across six wallets, agents negotiating with agents, gifting a task, reselling a held booking.
Split one booking across N wallets — the 6-person dinner problem: pooled x402 contributions with signed receipts and funded proofs
Meta-agent that composes paid skills — dinner + gift + transit in one request, with per-step receipts, powered by the suite
The cancel-worse-book-better move, automated — scans real inventory (Amadeus/RIDB) against your current booking, returns an actionable improvement report
Pay-per-poll price watching — every check returns a fresh snapshot plus delta vs your cursor (flights via Amadeus, crypto via CoinGecko)
Agent-to-agent price negotiation instruments — signed offers, counters, and agreements, each returned in-response
Standing orders for agents — mandate documents plus a client-side scheduler that pays per run and collects run reports
Fund someone else's agent task — buy a signed gift voucher, recipient's agent redeems it for execution with receipts
Transfer or resell held bookings between wallets — signed listings and reassigned booking tokens, all in-response
Did the merchant actually deliver? Reliability scores computed from signed fulfillment attestations
Arbitration for failed real-world tasks — signed case records with evidence hashes, status snapshots, and signed rulings
Point an agent at any repo's skill.md and it can read what the service does, what
each call costs, what comes back, and how to pay. To hand Claude or GPT the whole suite as tools,
use x402-mcp-commerce — every tool call
pays an upstream endpoint and returns the artifact with its receipt. Add
x402-agent-wallet for spending caps and
x402-approval-page to put a human in
the loop above a threshold. Build against
x402-agent-sandbox first — a fake town
of merchants using the same contracts as the real servers.