Coinbase is one clerk.

hosted checkout · USDC

SSDF's live rail. Create Checkout, signed webhook checkout.payment.success, refunds, rewards, Onramp. Hosted checkout is Base. Business can also receive USDC on Solana as a deposit destination — that is the gated x402 Solana door, not this checkout. Sandbox checkouts do not return x402_url. Auth is ES256/EdDSA CDP JWT, not X-CC-Api-Key. This is not Coinbase Commerce.

Business payment fee on hosted checkout; not the CDP $0.001 facilitator fee.

x402 facilitator · USDC (scheme varies)

Exact-scheme settler for /api/x402/{sku}. A successful Base settle that echoes extensions.bazaar is what Coinbase Bazaar indexes. Solana exact is the same clerk into a Business Solana USDC deposit — same SKU, not the Bazaar seed. Not advertised until SSDF_PAY_TO_SOLANA is set. Algorand is not on this facilitator. SSDF does not operate this facilitator — it calls verify/settle.

First 1,000 onchain facilitator tx / month free, then $0.001 per onchain tx. Fees follow onchain activity, not 402 challenges.

processor · USDC

US eligibility; Stripe lists all US states except New York. Requires API version 2026-05-27.preview. MPP is a different protocol that also uses HTTP 402. SSDF does not add Stripe. Mapping it here is the clerk grammar — Stripe is a surface, not a listing.

Documented ~1.5% per successful charge, rounded to the cent, in the 2026 machine-payments preview. Separate from Stripe MPP.

edge deferred · scheme-defined

Cloudflare co-launched the x402 Foundation with Coinbase (Sep 2025). Useful for inference micropayments. SSDF catalog prices start at $19 — deferred batching is the wrong tool here.

Deferred scheme batches sub-cent calls and settles on a separate cadence. Edge playground exists for tests without a wallet.

x402 facilitator · stablecoins

Independent facilitator. SSDF will not point 402 accepts at PayAI. Listed so an agent can tell a facilitator from a merchant.

Third-party facilitator. Confirm current fee on their site; early-2026 writeups put share behind Coinbase CDP.

self hosted · USDC

The protocol does not require a facilitator. SSDF's preview PAYMENT-SIGNATURE path is self-verify. Live keys send exact PAYMENT-SIGNATURE to the CDP facilitator instead of minting a demo Passport.

RPC + gas. No facilitator fee. You own replay, KYT, and chain watching.

issuer · USDC

GENIUS Act regulates permitted payment stablecoin issuers. Accepting USDC as a retailer is not issuing USDC. Do not conflate Circle, Coinbase, and SSDF.

Issuer economics. Not a checkout fee.