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Rails Index · October 2026

Monthly count of APIs and services by agentic payment rail, computed from LupaRiel's public catalog. Every number comes from the downloadable JSON.

Cutoff Research reviewed: x402 as of 2026-10-08 · PAP as of 2026-10-06 · AP2, ACP and MPP as of 2026-10-03 /rails-index/2026-10.json CC BY 4.0 Versión en español

Unique APIs
619
643 raw rows
Added since previous snapshot
+134
vs 2026-09-27
Removed
1
vs 2026-09-27
Multi-rail
22
3.6%

Payment rails

An API on several rails counts once per rail.

Rail APIs Share of unique Median entry price With published price
x402 281 45.4% US$0.01 235 / 281
AP2 127 20.5% no per-call price 0 / 127
ACP 87 14.1% no per-call price 0 / 87
MPP 146 23.6% US$0.005 36 / 146

AP2 and ACP do not publish a per-call price, the amount is set by each merchant at checkout.

Identity rail (not settlement)

PAP is identity/session. It is not a payment rail and is not added to the four above.

RailAPIs
PAP 1

By status

Corrected on 2026-10-09. See the erratum.

StatusAPIs%
Production 464 75.0%
Pilot 42 6.8%
Announced 113 18.3%

By category

CategoryAPIs%
Other 134 21.6%
Data / APIs 115 18.6%
AI / agents 94 15.2%
Commerce / retail 91 14.7%
Legal / compliance 48 7.8%
PSP / payments 47 7.6%
Infra / utilities 38 6.1%
Finance / crypto 31 5.0%
Health 21 3.4%

Additions and removals since the previous snapshot

Compared with the previous snapshot, 2026-09-27 (486 APIs, commit beb6ed4, the one in force on 2026-10-01), up to the 2026-10-09 cutoff.

+134 added · 1 removed · +133 net x402 +110AP2 +5ACP +7MPP +11PAP +1

See the 134 additions

Removed

  • Walmart ACP reclassified as doubtful ("Dudoso") on 2026-09-28 in the research; not published as an entry

Slug changes

Same entry with a new slug. Not counted as added or removed.

Methodology

  • Source. The same catalog published at /catalog.json, built from the research/ tables in the repo (commit 8577cac). Nothing is added by hand.
  • APIs. One deduplicated entry per API or service. Per rail: entries with evidence on that rail.
  • Status and category. Each entry's primary status (the most advanced among its rails: Production > Pilot > Announced) and category bucket, the same as the directory filters.
  • Cutoff. The cutoff is the edition date: the catalog as of commit 8577cac. Each source has its own review date (x402 as of 2026-10-08 · PAP as of 2026-10-06 · AP2, ACP and MPP as of 2026-10-03).
  • Additions and removals. Since the previous snapshot: compared by slug against the catalog rebuilt at the last commit that touched the research before the 1st of the month (00:00 ART). Each removal lists its reason. A slug change for the same entry is listed apart.
  • Median entry price. For each API on the rail, the price field of its first row with a price in the rail table. It counts only if it starts with a $ amount (USD/USDC, "~" and "Desde" allowed) and is per call or states no unit, and that first amount is used, ranges included. Variable, quote-based, per-time, per-page or per-physical-unit prices and fields without an amount are left out. The median is over the APIs with a price ("With published price"). AP2 and ACP do not publish a per-call price, the amount is set by each merchant at checkout: they read "no per-call price", never an estimate.
  • Rails. x402 · AP2 · ACP · MPP · PAP. Comparison: x402 vs AP2 vs ACP vs MPP · PAP. Full directory method: methodology (ES).

License and citation

Data under Creative Commons Attribution 4.0 (CC BY 4.0). Suggested citation:

LupaRiel, Rails Index 2026-10, v2 (cutoff 2026-10-09, erratum 2026-10-09). https://lupariel.com/en/rails-index/2026-10/. CC BY 4.0.

Download JSON · /rails-index/2026-10.json

Editions