The State of Agentic Commerce — April 2026

In March, we crossed 3,000 verified stores and started seeing the first non-Shopify platforms in the directory. We said the next question was whether UCP would remain a Shopify story or become a real multi-platform standard.

April answered that. We crossed 4,000 verified stores, Shopify migrated its entire fleet to the new v2026-04-08 spec in a four-day window, BigCommerce entered the directory with its first three stores, and WooCommerce and Magento integrations started appearing from independent developers. The ecosystem grew 33% in one month while simultaneously upgrading the protocol underneath.

This is the third monthly state-of-the-ecosystem report from UCP Checker. Here's what the data says.

The numbers

As of April 17, 2026:

• 4,014 verified UCP stores (up from ~3,000 in March, +33%)
• 4,481 total domains tracked
• 47,154 total checks run
• 1,436 new merchants discovered this month
• 866 new merchants this week alone
• 3,988 stores on the latest v2026-04-08 spec (99.4%)

The growth curve is worth examining. February was discovery: we scanned our first thousand Shopify stores and found UCP everywhere on the platform. March was expansion: we broadened the crawler, crossed 3,000, and started seeing non-Shopify manifests for the first time. April is consolidation: the store count grew 33%, but the more significant movement was the spec migration and the first signs of platform diversification.

The weekly run rate matters here. At 866 new merchants discovered this week alone, the ecosystem is adding roughly 125 stores per day. But the growth isn't organic in the way a consumer product grows — it comes in waves, driven by platform-level deployments. When Shopify flips a switch, hundreds of stores appear overnight. When BigCommerce ships UCP, three appear. The question for May isn't "how many stores" but "which platforms ship next" — because each platform deployment is a step function, not a slope.

The Shopify spec migration

This is the story of the month. Between April 13 and April 17, Shopify migrated nearly its entire UCP fleet from v2026-01-23 to v2026-04-08.

On April 13, our crawler showed 2 stores on the new spec. By April 17: 3,988. That's 3,986 stores upgraded in roughly four days — a coordinated platform-level migration, not individual merchants updating their manifests.

The v2026-04-08 spec introduced three breaking changes:

1. signing_keys moved from nested to root level. Previously at ucp.signing_keys, now at the document root alongside ucp. This is the structural change that required a manifest rewrite, not just a version bump.
2. Business profile distinction. The spec now formally separates business profiles (individual store manifests at /.well-known/ucp) from platform profiles, with different requirements for spec and schema fields on services and capabilities. Business profiles are lighter — spec and schema are optional.
3. a2a transport formally added. Google's Agent2Agent Protocol is now a recognised transport alongside REST, MCP, and Embedded, though adoption is effectively zero in the wild.

The migration means 99.4% of the verified directory is now on the latest spec. Only 26 stores remain on older versions: 19 on v2026-01-11, 6 on v2026-01-23, and 1 on v2026-01-14. These are almost entirely non-Shopify stores that need to upgrade manually.

For the full spec breakdown, see our v2026-04-08 spec announcement and the spec versions page.

Beyond Shopify: platform diversification accelerates

Shopify still dominates at 3,982 of 4,014 verified stores (99.2%). But the other 32 verified stores tell a more interesting story — these are developers who chose to publish a UCP manifest without a platform-level integration doing it for them.

BigCommerce entered the directory with its first three verified stores: untilgone.com, touchupdirect.com, and midwoodflowershop.com. All three are on v2026-04-08 with checkout and cart capabilities declared. Notably, their average manifest latency (~890ms) is significantly higher than Shopify's (~130ms) — BigCommerce manifests are served from the storefront origin rather than a CDN-cached endpoint. Platform-level latency differences like this will matter as agent response budgets tighten.

WooCommerce now has 3 verified stores, up from zero in March. These are hand-built integrations — WooCommerce doesn't have native UCP support, so each merchant published their manifest manually. We fixed a validation bug this month that was incorrectly rejecting WooCommerce manifests with payment_handlers: [] (valid for stores using checkout-link redirect flows).

Magento has 1 verified store. Custom/headless stacks account for 25 verified stores — the most architecturally diverse group, including our own ucpchecker.com manifest.

Salesforce Commerce Cloud has zero verified stores in the directory today. But industry signals suggest SFCC is exploring UCP support at the platform level — not as a one-off client integration, but as a feature that would ship to all Commerce Cloud merchants. If it follows the Shopify pattern — a single platform-level deployment bringing thousands of enterprise storefronts (Puma, Ralph Lauren, Under Armour, Adidas) into the ecosystem in one wave — the directory composition would shift significantly. SFCC is natively REST-based, so a REST-first UCP transport would be the natural fit, compared to Shopify's MCP-first approach. We're watching this closely.

The full platform breakdown is live on our new /platforms page.

How agents actually perform

The numbers above tell you which stores have UCP. This section tells you which stores work when an AI agent actually tries to shop them — and which models do it best.

Store benchmarks

Playground benchmarks grade stores A through F on end-to-end agent shopping performance:

The B+ tier at 422 stores is the most important number here. These stores are close — an agent can reliably discover, search, and cart them, but checkout friction (slow responses, variant mismatches, payment handler quirks) stops the flow short. The path from B+ to A is usually a single fix. The 289 F-grade stores are the other end: technically verified but functionally broken when an agent actually tries to shop them.

Model leaderboard

UCP Playground now supports 15 frontier LLMs from 7 vendors, tested against 76 unique stores, generating over $114,000 in aggregate cart value. The model leaderboard scores every model on search, cart completion, and checkout conversion:

And the speed rankings — because latency is the other dimension that matters:

Three takeaways

DeepSeek V3.2 leads the leaderboard. An open-weight model tops the composite shopping score at 63 — ahead of every Anthropic, Google, and OpenAI model. The agentic commerce stack is genuinely model-agnostic in practice, not just in spec language.

Search works everywhere. Checkout is the bottleneck. Every model scores above 70% on product search. But checkout conversion drops to 13–56% depending on the model. The gap between "can find products" and "can actually buy them" is the reliability frontier for the ecosystem. This is where the work is.

Reasoning models underperform. QwQ 32B (0% checkout), o4-mini (16.7%), Grok 3 Mini (13.3%), and DeepSeek R1 (21.4%) all score below 40. Models optimised for chain-of-thought reasoning burn tokens on deliberation and struggle to execute the simple, sequential tool-call patterns shopping requires. The best shopping agents are fast and decisive, not thoughtful.

Full model profiles are on the Playground models page.

The reliability gap: verified is not ready

This is the editorial point we want to make clearly, because the headline number (4,014 verified stores) obscures the more important one: 9 stores score A.

Four thousand stores have valid UCP manifests. Nine of them deliver a flawless end-to-end agent shopping experience. That's a 0.2% flawless rate. The gap between "technically verified" and "actually shoppable by an AI agent without friction" is the central infrastructure problem for agentic commerce in 2026.

The B+ tier — 422 stores — is where the leverage is. These stores work most of the time. An agent can discover them, search their catalog, build a cart, and usually reach a checkout URL. But "usually" isn't good enough when the agent is spending someone's money. The failures at B+ level are specific and fixable:

• Cart variant mismatches — the agent selects a size/colour variant that doesn't match the store's internal variant ID scheme. The cart call succeeds but adds the wrong item.
• Payment handler timeouts — the tokenization step takes longer than the agent's timeout window, and the session drops silently.
• Stale product data — the catalog returns products that are out of stock by the time the agent tries to cart them. No error — just an empty cart.
• Checkout redirect loops — the checkout URL the store returns sends the agent into an authentication loop that a human browser would handle with cookies but an MCP client can't.

Each of these is a single-fix problem for the store operator. But at scale, across 422 stores, the aggregate effect is that agents fail more often than they succeed at the final step. The ecosystem doesn't need more stores. It needs the stores it has to work more reliably. That's the infrastructure investment that will actually unlock agent commerce at scale — and it's where we're focusing our tooling work for May.

Capability coverage: the ceiling hasn't moved

Across 4,014 verified stores:

Same pattern as March. Checkout and cart are effectively universal because Shopify ships them by default. The advanced capabilities — identity, loyalty, payment — haven't moved. The gap between "technically verified" and "deeply agent-ready" is still the story. Until more stores declare capabilities beyond the Shopify defaults, the ecosystem depth chart stays flat.

The broader ecosystem

April was quieter on the announcements front than March — which saw Splitit, PayPal, and Google all making public UCP commitments in a single week. But the signals that matter in April are structural, not press-release-shaped.

Shopify's fleet-wide spec migration is itself an ecosystem signal. It demonstrates that a major platform can coordinate a breaking spec upgrade across thousands of stores in days, not months. Every other platform considering UCP adoption now has a reference point for what a managed migration looks like. The v2026-04-08 changes (signing_keys relocation, business profile distinction) were non-trivial — and Shopify shipped them to its entire fleet without a single store going offline. That's the kind of platform engineering confidence that accelerates the next platform's decision to build UCP support.

The endorsed partner roster continues to grow. Adyen, American Express, Mastercard, Stripe, Visa, Checkout.com, Affirm, Splitit, and PayPal are all publicly committed to the protocol's payment layer. For any platform evaluating UCP, the payment handler ecosystem is no longer a gap — it's arguably the most mature part of the stack.

The model ecosystem is widening faster than the store ecosystem. In February, we tested 3 models. In March, 8. In April, 16 — from 7 vendors across the US, China, and Europe. The number of AI models that can speak MCP and execute a UCP shopping flow is growing faster than the number of stores that can serve one. This suggests the bottleneck is shifting from "agents that can shop" to "stores that can be shopped reliably" — which circles back to the reliability gap above.

What we shipped

Heavy shipping month on the tooling side:

• Side-by-side store comparison — compare any two stores head-to-head on metrics, capabilities, transports, and payment handlers. Embeddable via iframe for blog posts and docs.
• Platform pages — live landing pages for Shopify, BigCommerce, WooCommerce, Magento, and Custom. Leaderboards, capability coverage, and transport adoption — auto-populates as stores verify.
• /.well-known/ucp developer guide — field reference, minimal examples, publishing guides for Nginx/Cloudflare/Node, the six most common validation mistakes.
• Product discovery guide — the MCP tool call sequence agents use to find and buy products. Live demo, discovery-ready stores, three-way CTA to Playground + Registry + Rails.
• Build an Agent quickstart — from zero to a working agent in 30 minutes. Copy-paste code in Python and TypeScript.
• Spec validation fixes — accepted the payment.handlers nested format (WooCommerce), downgraded empty payment_handlers: [] from hard fail to warning, upgraded our own manifest to v2026-04-08.

What to watch in May

Salesforce Commerce Cloud. First platform-level deployment from the enterprise tier would be the most significant ecosystem event since Shopify's initial rollout. We'll catch any SFCC store that publishes on the next crawl.

The B+ → A path. 422 stores are one fix away from flawless agent shopping. We're building tooling to surface the specific issue per store so operators can action it.

Non-Shopify growth rate. 32 non-Shopify stores this month vs ~15 last month. If this doubles again in May, UCP stops being a "Shopify project" and becomes a genuine multi-platform standard.

AP2 / A2A adoption. Zero stores declare either protocol. The v2026-04-08 spec formally added a2a as a transport. First adopter will be notable.

Sources

All data comes from the UCP Checker crawler, which re-checks every tracked domain at least every 24 hours. The raw verified-merchant dataset is published monthly on Hugging Face under CC-BY 4.0.

• Browse the directory: ucpchecker.com/directory
• Track adoption live: ucpchecker.com/stats
• Compare two stores: ucpchecker.com/compare
• Platform breakdown: ucpchecker.com/platforms
• Build your own agent: ucpchecker.com/agents