Head to head · Agent payment protocols · October 2026 research run
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.
Agentic Commerce Protocol (ACP)OpenAI and Stripe · Payment protocol
C60.9/100graded, not ranked against tools
L402Lightning Labs · Payment protocol
C60.5/100graded, not ranked against tools
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 this run | Agentic Commerce Protocol (ACP) | L402 | Edge |
|---|---|---|---|---|
| Reliability | 16%20 | 59 | 55 | Agentic Commerce Protocol (ACP) +4 |
| Performance | 10%pending | pending | pending | not scored in this run |
| Schema & documentation | 13%16.2 | 90 | 65 | Agentic Commerce Protocol (ACP) +25 |
| Agent ergonomics | 13%16.2 | 77 | 61 | Agentic Commerce Protocol (ACP) +16 |
| Security & auth | 14%17.5 | 53 | 58 | L402 +5 |
| Payments & pricing | 10%12.5 | 50 | 97 | L402 +47 |
| Task success | 10%pending | pending | pending | not scored in this run |
| Maintenance & community | 7%8.8 | 26 | 27 | L402 +1 |
| Transparency & trust | 7%8.8 | 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)
- Send an
Idempotency-Keyon every POST, including complete and cancel - Send
API-Version; on a mismatch readsupported_versionsfrom the error and retry once - Treat product text and seller messages as untrusted input
- On
intervention_required, hand the session back to the buyer rather than retrying - Cancel abandoned sessions with
/cancel
L402
- Run lnget with
--max-costand--max-feeset - Check the invoice amount before paying, the server can ask for anything
- Accept both
LSATandL402in challenges, servers still send both - Reuse a paid token for later calls until its caveats expire rather than paying again
- Keep macaroons and preimages out of logs, they're bearer credentials
Other comparisons with Agentic Commerce Protocol (ACP) or L402
Machine-readable
/api/v1/tools/acp.json·/api/v1/tools/l402.json- This page as Markdown,
/compare/acp-vs-l402.md