HTTP 402 Payment Required into a machine-payment rail. The server quotes payment requirements; the agent attaches a signed USDC authorization (typically gasless EIP-3009 on Base); a facilitator verifies and settles; the server returns the resource. Median tickets are cents; settlement is ~99% USDC.
The flow, in five steps
1. Agent GETs a resource
2. Server → 402 + payment requirements (amount, asset, network, pay-to, scheme)
3. Agent signs payment payload (EIP-3009 gasless USDC) and retries
4. Facilitator verifies and settles on-chain
5. Server returns the resourceOpen source at x402-foundation/x402 with TypeScript and Go implementations and adapters for Express, Hono, Next, and MCP. Stewardship sits with the Linux Foundation; the member list spans AWS, Google, Visa, Mastercard, Stripe, Circle, Cloudflare, Shopify, and the Solana Foundation. The multi-rail competitor is Stripe/Tempo’s MPP — cards, crypto, and Lightning in one HTTP flow. We track both; the graph is neutral about rails.
The measured numbers
| Signal | Value | Window | Source |
|---|---|---|---|
| Agent payments settled | $73M · 176M txs | May 2025 – Apr 2026 | Keyrock + Coinbase + Tempo |
| Average ticket | ~$0.31 | same window | Keyrock “Who Pays the Agent” |
| Below the $0.30 card-fee floor | 76% | same window | Keyrock |
| USDC share of settlement | 98.6–99% | 2025–2026 | Keyrock; x402 flow data |
| Cumulative x402 reports | 165M+ payments · ~$50M | earlier 2026 | ecosystem reports |
| x402scan live window | ~26M txs · $1.45M · 21.2k buyers | 30d, observed 2026-09 | x402scan |
| Typical payment size | $0.01–$0.10 | distribution | multiple explorers |
Explorers and reports will not match each other — they measure different objects over different windows. That is why every number above carries its window and source, and why our own tiles are timestamped. Publishing rules →
The vanity-volume problem
Volume is real and polluted: Coinbase estimated 25–30% of some 30-day windows may be leaderboard farming. Before x402 volume means anything, you must separate economic transactions from vanity loops:
- Require repeat counterparties — a buyer that pays one seller once, for dust, is a ping, not demand.
- Drop self-payments and circular flows between wallets with a common funding parent.
- Design around micropayment histograms, not mean volume — averages are pulled by outliers.
Our panels ship with the economic-vs-vanity toggle defaulted to economic. The unfiltered number is available one click away, labeled for what it is.
Why the USDC monoculture is a tile, not a trophy
~99% single-issuer settlement is operational convenience today and a single point of failure tomorrow. The graph tracks USDT, FDUSD, PYUSD, and EURC share weekly — multi-stablecoin routing is one of the clearest product gaps in the sector. The stablecoin mix lives on the data panels as a risk widget.