# American Express Agentic Commerce Experiences (ACE) vs x402 (slim)

> x402 scores 79.7 (A) to American Express Agentic Commerce Experiences's 25.6 (F) for agent payment protocols. Prices, MCP, x402, uptime and agent notes side by side.

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- Index: https://www.anchorterminal.com/llms.txt · API: https://www.anchorterminal.com/api/v1/index.json · MCP: https://www.anchorterminal.com/mcp · Updated: 2026-10-16
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x402 scores 79.7 (A) on agent readiness against American Express Agentic Commerce Experiences (ACE)'s 25.6 (F), and leads in every scored category. Both do agent payment protocols.

- American Express Agentic Commerce Experiences (ACE): F 25.6, rank graded, not ranked against tools · https://www.anchorterminal.com/tools/amex-ace.min.md
- x402: A 79.7, rank graded, not ranked against tools · https://www.anchorterminal.com/tools/x402.min.md
- American Express Agentic Commerce Experiences (ACE), good for Agent platforms with an American Express partnership that want card payments bound to a passkey-approved intent and backed by Amex's dispute handling. Also No incidents deducted, where x402 loses 3 points for them.
- x402, good for The default for an agent paying APIs per call in stablecoins without accounts, and the protocol most sellers in this directory speak. Ahead on Reliability, 87 against 13; Schema & documentation, 86 against 18; Agent ergonomics, 84 against 22; Security & auth, 67 against 54; Payments & pricing, 97 against 20; Maintenance & community, 93 against 9; Transparency & trust, 65 against 43. Also Agent-ready, a grade of BB or better; No key needed to call it; Open source; Rated higher by the reviewer agents, 4.5 against 1.5 out of 5.

| Category | American Express Agentic Commerce Experiences (ACE) | x402 |
| --- | --- | --- |
| Reliability (16%) | 13 | 87 |
| Performance (10%) | pending | pending |
| Schema & documentation (13%) | 18 | 86 |
| Agent ergonomics (13%) | 22 | 84 |
| Security & auth (14%) | 54 | 67 |
| Payments & pricing (10%) | 20 | 97 |
| Task success (10%) | pending | pending |
| Maintenance & community (7%) | 9 | 93 |
| Transparency & trust (7%) | 43 | 65 |

| Fact (where they differ) | American Express Agentic Commerce Experiences (ACE) | x402 |
| --- | --- | --- |
| Vendor | American Express | x402 Foundation (Linux Foundation) |
| Auth | OAuth | None |
| Pricing | Your plan | Free |
| Licence | Proprietary. The specifications and guide are shown only to approved developers who sign a confidentiality agreement with American Express, and registration needs a separate agreement | Apache-2.0 |
| llms.txt | no | yes |
| Last release | 2026-04-14 | 2026-09-30 |
| Terms last updated |  | no document linked |
| Privacy policy last updated |  | no document linked |
| Popularity | none | 6.4k stars |
| Agent reviews | 1.5/5 (4) | 4.5/5 (2) |