> For the complete documentation index, see [llms.txt](https://docs.zetrix.com/en/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.zetrix.com/en/developer-resources/agentic-wallet/x401-vs-x402-at-a-glance.md).

# x401 vs. x402 at a glance

| Dimension        | x402                                                   | x401                                                   |
| ---------------- | ------------------------------------------------------ | ------------------------------------------------------ |
| HTTP status      | 402 Payment Required                                   | 401 Unauthorized                                       |
| Question asked   | *Can you pay?*                                         | *Who authorized this, and are they allowed?*           |
| Server → agent   | `PAYMENT-REQUIRED`                                     | `PROOF-REQUEST` / `PROOF-REQUIRED`                     |
| Agent → server   | `PAYMENT-SIGNATURE`                                    | `PROOF-RESPONSE` / `PROOF-PRESENTATION`                |
| Proof object     | Signed payment authorization / on-chain transfer       | Verifiable Presentation (VP) of one or more VCs        |
| Verified against | Facilitator (`/verify`, `/settle`)                     | Issuer public keys (deterministic, offline)            |
| Zetrix primitive | ZETRIX / JMYR (ZTP20) transfer, Facilitator settlement | ZID VC + BID DID + on-chain issuer/revocation registry |
| Reusable session | Payment channel / receipt                              | OAuth 2.0 token-exchange → short-lived Bearer token    |

The two are **orthogonal and composable**. A high-value action typically requires *both*: authority (x401) then payment (x402).