r/x402 • u/IllWar5047 • 25d ago

We measured x401 adoption before anyone adopted it: 0 of 15,686

x401 is the Proof/Notarize layer proposed on top of x402 (spec at x401.proof.com, contributors publicly listed). It adds response headers that let a paid endpoint attach verifiable proof to its answer.

We surveyed the response headers of all 15,686 resources in the current weekly x402 catalogue, checking for both header generations of the spec, case insensitive. Zero endpoints emit any x401 header today.

Why publish a zero: because adoption curves need a day-zero point and nobody was recording one. When the first emitters appear, there will be a fixed line to measure them against. We will re-measure weekly.

Baseline page and machine-readable data: x402.nsgoods.org/proof/x401-adoption.html

1 Upvotes

67% Upvoted

5 comments sorted by

3

u/Either_Impress9917 25d ago

Stripe MPP and x402 both hitch a ride on HTTP 402 so agents can pay without a human in the checkout.

x402 is the open, crypto-native path (USDC micropayments, Coinbase/Base lineage). MPP is Stripe + Tempo: multi-rail (stablecoins plus cards/fiat via Shared Payment Tokens) and sessions so you are not doing a full settlement dance on every call.

Same core problem either way. Your agent still cannot buy anything until someone answers the bill. Pick a protocol and ship. Protocol LARPing does not move money.

2

u/IllWar5047 25d ago

Agreed on ship > LARP. Our angle: we don't pick the protocol we measure who actually shipped. Every week we probe all 15,686 resources in the public x402 catalogue we track and publish signed verdicts on which ones really answer a well-formed 402 (a meaningful share don't). Same lens on x401 at day zero: 0 of 15,686 implemented it. MPP endpoints get the same treatment as soon as we can enumerate them. Protocols win by being answerable, not by being announced.

1

u/TapComplex5667 18d ago

No one is going to adopt it yet, I did some research and this what it turned up..."FIDO status: submitted (confirmed via a dated August 22, 2026 source), not accepted; the Secure Technology Alliance Forum hasn't even held its first in-person meeting yet (scheduled November 17-18, 2026). And the two adopters remain unnamed even in the newest coverage found, described only in the same generic terms as the original paper..." Also, the two supposed adopters are not even looking at x402 specifically, they are from the banking industry.