x402 turns the dormant HTTP 402 Payment Required status into a stablecoin paywall settled by a facilitator. This workbench decodes the base64 PAYMENT-REQUIRED / PAYMENT-SIGNATURE / PAYMENT-RESPONSE headers, lints an exact-scheme PaymentPayload, walks the request → /verify → /settle flow, and shows which scheme×network pairs are live.
⚠ x402 is an evolving Linux Foundation project. Header names and the flow are stable, but the exact-scheme sub-fields are illustrative (EIP-3009 style) — confirm field names against the x402 spec before building. Nothing here touches a chain or facilitator.
x402exact schemeZero PIIClient-Side · No Network
Scope & reliance —🔒 All inputs are processed locally in your browser. No data is transmitted. Do not enter real personal data — use synthetic or anonymised inputs only. Decoding is exact (base64 → JSON). The linter checks the documented top-level shape; scheme-specific sub-fields are illustrative and flagged as such. Do not paste a real signed payload that authorises a live transfer. Deterministic · zero PII · CC BY 4.0.
▸ Decode an x402 header value
Paste a base64 header value (with or without the PAYMENT-REQUIRED: / PAYMENT-SIGNATURE: / PAYMENT-RESPONSE: prefix). It is base64-decoded and pretty-printed locally.
▸ Lint an exact-scheme PaymentPayload
Paste a decoded PaymentPayload JSON. Top-level shape is checked against the documented fields; the exact-EVM authorization sub-fields are validated as illustrative (EIP-3009 style).
▸ Walk the HTTP-402 flow
A deterministic walkthrough of the request → 402 → sign → re-request → verify → settle → 200 sequence with example objects.
▸ Scheme × Network support (Jun 2026 snapshot)
Which (scheme, network) pairs the Coinbase-hosted facilitator supported as of mid-2026. Verify current support against x402.org.