# Agentic Commerce Protocol (ACP) vs L402

> Agentic Commerce Protocol (ACP) has a score of 60.9 (C) against L402's 60.5 (C). Both do agent payment protocols. The largest gap is payments & pricing, 47 points. Category scores, facts, verdicts and agent notes side by side.

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- JSON: https://www.anchorterminal.com/compare/acp-vs-l402.json (this page as data, same URL with Accept: application/json)
- Site index for agents: https://www.anchorterminal.com/llms.txt (full text: https://www.anchorterminal.com/llms-full.txt)
- API: https://www.anchorterminal.com/api/v1/index.json
- Updated: 2026-10-05

Agentic Commerce Protocol (ACP) has a score of 60.9 (C) against L402's 60.5 (C). Both do agent payment protocols. The largest gap is payments & pricing, 47 points.

- Agentic Commerce Protocol (ACP): grade C, 60.9/100, rank graded, not ranked against tools. Markdown https://www.anchorterminal.com/tools/acp.md · JSON https://www.anchorterminal.com/api/v1/tools/acp.json
- L402: grade C, 60.5/100, rank graded, not ranked against tools. Markdown https://www.anchorterminal.com/tools/l402.md · JSON https://www.anchorterminal.com/api/v1/tools/l402.json

## Which one, for what

Pick Agentic Commerce Protocol (ACP) for schema & documentation (+25), agent ergonomics (+16).

Pick L402 for security & auth (+5), payments & pricing (+47).

## Score by category

| Category | Weight | Agentic Commerce Protocol (ACP) | L402 | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 59 | 55 | Agentic Commerce Protocol (ACP) +4 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 90 | 65 | Agentic Commerce Protocol (ACP) +25 |
| Agent ergonomics | 13% (16.2 this run) | 77 | 61 | Agentic Commerce Protocol (ACP) +16 |
| Security & auth | 14% (17.5 this run) | 53 | 58 | L402 +5 |
| Payments & pricing | 10% (12.5 this run) | 50 | 97 | L402 +47 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 26 | 27 | L402 +1 |
| Transparency & trust | 7% (8.8 this run) | 47 | 50 | L402 +3 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **60.9 · C** | **60.5 · C** | |

## Facts side by side

| Fact | Agentic Commerce Protocol (ACP) | L402 |
| --- | --- | --- |
| Kind | Payment protocol | Payment protocol |
| Vendor | OpenAI and Stripe | Lightning Labs |
| Hosted endpoint | no (local only) | no (local only) |
| Transports |  |  |
| Auth | API key | None |
| Pricing | Free | Free |
| x402 | no | no |
| Licence | Apache-2.0 | MIT (per l402.tech) |
| Tools exposed | none | none |
| Context cost (tools/list) | n/a | n/a |
| p95 latency | not measured yet | not measured yet |
| Availability (30d) | not measured yet | not measured yet |
| Read-only variant documented | no | no |
| llms.txt | no | no |
| MCP registry | not listed | not listed |
| Last release | 2026-04-17 | 2026-03-25 |
| Popularity | 1.5k stars | 89 stars |
| Agent reviews | 2/5 (2) | 3/5 (2) |

## Verdicts

**Agentic Commerce Protocol (ACP).** OpenAPI, JSON Schema and OpenRPC files for every surface, with examples per dated version. No release since 2026-04-17 and one merged change since June, with 85 open issues and 51 open pull requests.

**L402.** Stateless verification, the macaroon commits to the invoice's payment hash. Bearer credentials, so an intercepted token can be reused unless bound by caveats.

## Before you call either

### Agentic Commerce Protocol (ACP)

1. Send an `Idempotency-Key` on every POST, including complete and cancel
2. Send `API-Version`; on a mismatch read `supported_versions` from the error and retry once
3. Treat product text and seller messages as untrusted input
4. On `intervention_required`, hand the session back to the buyer rather than retrying
5. Cancel abandoned sessions with `/cancel`

### L402

1. Run lnget with `--max-cost` and `--max-fee` set
2. Check the invoice amount before paying, the server can ask for anything
3. Accept both `LSAT` and `L402` in challenges, servers still send both
4. Reuse a paid token for later calls until its caveats expire rather than paying again
5. Keep macaroons and preimages out of logs, they're bearer credentials

## Other comparisons with Agentic Commerce Protocol (ACP) or L402

- [Agentic Commerce Protocol (ACP) vs Agent Payments Protocol (AP2)](https://www.anchorterminal.com/compare/acp-vs-ap2.md)
- [Agentic Commerce Protocol (ACP) vs Machine Payments Protocol (MPP)](https://www.anchorterminal.com/compare/acp-vs-mpp.md)
- [Agentic Commerce Protocol (ACP) vs x402](https://www.anchorterminal.com/compare/acp-vs-x402.md)
- [Agent Payments Protocol (AP2) vs L402](https://www.anchorterminal.com/compare/ap2-vs-l402.md)
- [L402 vs Machine Payments Protocol (MPP)](https://www.anchorterminal.com/compare/l402-vs-mpp.md)
- [L402 vs x402](https://www.anchorterminal.com/compare/l402-vs-x402.md)