# s402 vs x402

Both belong to the HTTP 402 family group on this map. The map lists them as complementary: sites and agents commonly implement both. x402 is a prerequisite of s402.

[7 Pay](/category/pay/) [s402](/protocols/s402/) · [7 Pay](/category/pay/) [x402](/protocols/x402/)

|  | [s402](/protocols/s402/) s402 | [x402](/protocols/x402/) |
| --- | --- | --- |
| Lifecycle step | 7 Pay: Settle the bill | 7 Pay: Settle the bill |
| Answers | How can an agent pay a Sui-native resource using six payment schemes (including prepaid batching and escrow), while staying wire-compatible with plain x402 clients? | How can an HTTP client pay per-request or per-resource, in stablecoins, without accounts, API keys, or signup? |
| Governed by | Single open-source project (s402-protocol on GitHub); no standards body, no foundation; explicitly a 'profile' of x402 rather than a competing standards effort | x402 Foundation, a Series of LF Projects, LLC (Linux Foundation); operational launch announced 2026-07-14; Executive Director Michael Hursta from 2026-10-01; 50+ members |
| Status (issuer's words) | Archived repository (observed 2026-10-16) | Open, neutral standard for internet-native payments |
| Phase | deprecated | living |
| Version | Wire Format Specification v1, Draft, dated March 2026 (repository has continued past this to align with x402 v2) (2026-03) | x402 protocol specification v2, transports-v2/http.md |
| Form / transport | HTTP header | HTTP header |
| Found at | none — no /.well-known/s402.json was found; discovery is per-request via the 402 envelope, matching x402's model | none — signalled per-request via the 402 status code, not a fixed well-known path |
| Adoption | unmeasured | claimed — x402 Foundation (x402.org live dashboard) |
| Evidence | 4 verified | 5 verified |
| Primary use case | Accept payments from agents | Accept payments from agents |
| Last verified | 2026-10-19 (current) | 2026-10-19 (current) |
| Specification | [https://raw.githubusercontent.com/s402-protocol/core/main/docs/specification.md](https://raw.githubusercontent.com/s402-protocol/core/main/docs/specification.md) | [https://github.com/x402-foundation/x402/blob/main/specs/transports-v2/http.md](https://github.com/x402-foundation/x402/blob/main/specs/transports-v2/http.md) |

## When to use which

- Choose s402 when your question is “How can an agent pay a Sui-native resource using six payment schemes (including prepaid batching and escrow), while staying wire-compatible with plain x402 clients?” and you accept its maturity: phase deprecated, adoption unmeasured. It is no longer maintained; prefer its successor.
- Choose x402 when your question is “How can an HTTP client pay per-request or per-resource, in stablecoins, without accounts, API keys, or signup?” and you accept its maturity: phase living, adoption claimed (x402 Foundation (x402.org live dashboard)).

Guidance is derived from the two records (question, phase, adoption, prerequisites, pairings), not from opinion. Each record's page carries its numbered references.

## Read the full articles

- [s402](/protocols/s402/): How can an agent pay a Sui-native resource using six payment schemes (including prepaid batching and escrow), while staying wire-compatible with plain x402 clients?
- [x402](/protocols/x402/): How can an HTTP client pay per-request or per-resource, in stablecoins, without accounts, API keys, or signup?

Ask the MCP server to compare any two: the compare-protocols prompt, or get on both ids. [Connect](/connect/).

[s402.json](/data/protocols/s402.json) · [x402.json](/data/protocols/x402.json) · [Markdown](/compare/s402-vs-x402/index.md)