The state of UCP
Who publishes a UCP profile across the web, read every month, and how well the stores we check follow the spec, read every day.
Every month we read about 4 million ecommerce sites with measurable shopper traffic, the same sites each month, not only the stores we check. About 3.7 million were live ecommerce sites, and the shares below are of those. A UCP profile counts when the site serves it publicly at /.well-known/ucp and it passes the official validator; a profile behind a login or a bot wall can't be counted.
UCP by traffic rank
Every ecommerce site we read in each traffic band, by what we found. The figure on the right is the band's share of live ecommerce sites with a valid public UCP profile. The biggest sites turn automated visitors away most, so the top bands' figures are the least certain
Capabilities declared
Of the about 1.2 million sites with a valid public UCP profile; a site can declare several
Spec adoption
Every capability in the 2026-08-25 release, and the share of the about 1.2 million sites with a valid public UCP profile that declare it; a site can declare several
Every site read, by result
What a request for the UCP profile found, as shares of every ecommerce site read (about 4 million). Rows marked out of the live count are left out of the about 3.7 million live ecommerce sites; the headline 31.8% is of those live sites
| Valid UCP profile | 1.2 million | 29.4% |
| No UCP profile | 2.5 million | 62.5% |
| Unreachable (DNS, certificate, server error, timeout) out of the live count | 99,000 | 2.5% |
| Turns automated visitors away out of the live count | 160,000 | 4.1% |
| Not live: closed, password, forwards, not a store out of the live count | 42,000 | 1% |
| Profile fails validation | 19,000 | 0.5% |
UCP by platform
Live ecommerce sites on each platform; publish and valid are shares of them (publish = serves a UCP profile, valid = the profile passes)
27 of the 82 platforms we identified serve a UCP profile on at least one site; on 22, at least one passes the official validator.
| Platform | Live sites | Publish | Valid | |
|---|---|---|---|---|
| 1 | WooCommerce | 880,000 | under 0.1% | under 0.1% |
| 2 | Shopify | 720,000 | 100% | 100% |
| 3 | Wix | 400,000 | 99.5% | 99.5% |
| 4 | Squarespace | 230,000 | under 0.1% | under 0.1% |
| 5 | PrestaShop | 59,000 | 0.1% | under 0.1% |
| 6 | 1C-Bitrix | 49,000 | under 0.1% | under 0.1% |
| 7 | Tiendanube | 47,000 | under 0.1% | under 0.1% |
| Platform | Live sites | Publish | Valid | |
|---|---|---|---|---|
| 8 | OpenCart | 45,000 | under 0.1% | under 0.1% |
| 9 | Square Online | 30,000 | none | none |
| 10 | Magento | 27,000 | 0.8% | 0.5% |
| 11 | Cafe24 | 18,000 | none | none |
| 12 | BigCommerce | 16,000 | 97% | 96.9% |
| 13 | Shoptet | 15,000 | over 99.9% | over 99.9% |
| – | Platform not identified | 1,030,000 | 0.5% | 0.2% |
HTTP answers at /.well-known/ucp
Of the about 3.7 million live ecommerce sites
Release declared
Of the about 1.2 million sites with a valid public UCP profile
CDN in front of the store
Of the about 3.7 million live ecommerce sites, behind each CDN
Bot management in front of the store
Of the about 3.7 million live ecommerce sites: what an agent meets before the profile
The stores UCP Checker checks every day: how well UCP agents can use what they publish. Not the whole market; the wider web covers that.
What we found at /.well-known/ucp
Of the stores we check
Which release
Of the stores we check with a valid profile
What the score says
Of the stores we check that we could score
What profiles declare
Share of valid profiles; a profile can declare several
AI crawlers disallowed in robots.txt
Stores we check whose robots.txt disallows each crawler
Transports declared
Of the stores we check with a valid profile; a profile can declare several
What else an agent can read
Stores with a valid profile that also serve each
MCP tools listed
Stores that declare MCP, listing each tool the spec names
Accounts and signing
Of the stores we check with a valid profile
Rules passed least often
Share passing each UCP Checker rule, of the stores it applies to; security rules are never shown
Found and usable
Each bubble is the share of stores with a valid profile at that point: across, how many of five things an agent can find (llms.txt, WebMCP, sitemap, Open Graph, Organization schema); up, how many capabilities the profile declares
The five things: llms.txt, WebMCP, a sitemap, Open Graph tags and Organization schema. Hover or tap a bubble for what it means.
Every open proposal and recent merge in the spec repo, by area and stage; the Area and Stage filters carry the counts.
| # | Change | Area | Stage | Date |
|---|---|---|---|---|
| 1097 | Add catalog recommendations extension | – | open | filed 14 Nov |
| 902 | Search for a substituteLets a catalog search say why it is asking, such as a recommendation or a swap for given products. | Shopping | needs TC review | filed 5 Oct |
| 1063 | AP2 Mandates — signed, mandate-bound receipts for every charge and refund after checkout | Payments | proposal | filed 10 Nov |
| 1072 | Add optional payer identification to payment instruments | Payments | draft PR | filed 11 Nov |
| 1096 | Add open-enumeration examples and value audit tool | – | open | filed 14 Nov |
| 1095 | Audit of open-enumeration fields missing "examples" and uncataloged doc values (STC 2026-11-06 follow-up) | – | proposal | filed 14 Nov |
| 1092 | Operator extension for Ask capability | – | needs TC review | filed 13 Nov |
| 922 | Local Services councilA Domain Tech Council for scheduling and bookings, starting from the Universal Scheduling Protocol (USP), which the Governing Council calls an initial sketch. Our coverage: UCP Local Services Council Approved: What Happens Next for Bookings · UCP Local Services: What the Charter for a Booking Council Proposes | – | approved | filed 9 Oct |
| 947 | B2B Procurement councilA Domain Tech Council for procurement. Our coverage: UCP B2B Procurement Council Approved: What Happens Next for Business Buying · UCP for B2B: An Agent Buys on Net 30 Terms, Step by Step | – | approved | filed 14 Oct |
| 1073 | Add WebMCP transport binding | – | needs TC review | filed 11 Nov |
| 1076 | Add an "Ask AI about UCP" assistant to ucp.dev | – | open | filed 12 Nov |
| 866 | Bulk catalog feedsA feed capability for whole-catalog files, from the Bulk Product Discovery working group. Our coverage: UCP Gets a Product Feed: Inside the Catalog Feed Draft · Video, 3D and Image Variants in UCP: What the New Media Type Adds, and What Stores Send Today | Shopping | open | filed 25 Sep |
| 1075 | A payment handler for processing out of band payments like cash, check, and invoice | Payments | draft PR | filed 12 Nov |
| 1090 | CI-run reference implementation built on ucp-schema types | – | draft PR | filed 13 Nov |
| 1089 | Snapshot applied discounts onto the order | – | open | filed 13 Nov |
| 1091 | Subscription capability (identity, Get and List) | – | proposal | filed 13 Nov |
| 1081 | Add subscription capability with Get and List Subscriptions | – | draft PR | filed 13 Nov |
| 879 | Get_product: define server behavior when selected repeats an option name | Shopping | proposal | filed 29 Sep |
| 1069 | Add product brand and variant mpn, clarify barcodes | – | open | filed 11 Nov |
| 1061 | Add pack extension for catalog variants | – | draft PR | filed 8 Nov |
| 1060 | Pack content and net/drained weight for Shopping catalog items Our coverage: UCP B2B Procurement Council Approved: What Happens Next for Business Buying | – | proposal | filed 8 Nov |
| 1071 | Add stable key to product options | – | open | filed 11 Nov |
| 1070 | Add variant condition | – | open | filed 11 Nov |
| 949 | Checkout never requires ready_for_complete, and the two REST samples disagree on it | Shopping | proposal | filed 14 Oct |
| 987 | Split payments across deferred schedules Our coverage: UCP Subscriptions Explained: Purchase Options from Catalog to Order, Step by Step | Payments | open | filed 23 Oct |
Showing the 25 with the latest activity of 245. All in the spec repo ›
The wider web is our monthly market read of ecommerce sites with measurable shopper traffic; the stores we check are checked every day. Each chart says what its shares are of. Methodology → · Citing and reuse: quote any figure with credit to UCP Checker and a link to the page and month; anything more needs our permission.
