Why We Built UCPList
UCP launched in January 2026 and the ecosystem fragmented fast. There was no map. So we built one.
The Problem
UCP launched in January 2026. Within a few weeks, validators, SDKs, merchant implementations, checkout libraries, and agent integrations were popping up all over GitHub. Genuinely interesting stuff.
But finding any of it was a mess.
Search for "UCP tools" and you'd get a mix of official spec docs, one-off blog posts, and random GitHub repos. The official docs at ucp.dev cover the protocol well, but they're not a directory. There was no single place that answered the basic question: what's actually out there?
That's what drove this. Not a grand vision about owning the UCP ecosystem. Just a practical frustration: the space was fragmenting fast, and there was no map.
So We Built One
UCPList started as a spreadsheet. A list of tools we'd found while researching the space: validators, merchant implementations, Shopify apps, Python SDKs, checkout helpers. Stuff that existed but was hard to find unless you already knew where to look.
The spreadsheet became a site. The site became a directory.
The goal was simple: if you're a developer building with UCP, a merchant figuring out whether to adopt it, or an AI agent builder looking for UCP-enabled endpoints to integrate, you should be able to come here and find what you need in under five minutes.
We tried to be comprehensive rather than curated. Not just merchants (checkout.directory already does that). Everything: platforms, payment handlers, SDKs, developer tools, agent integrations, guides. The full picture of what the ecosystem looks like right now.
We also tried to be honest about status. A listing that says "Announced" means announced. Not live. Not verified. Announced. The directory makes this distinction explicit for every entry, so you don't waste time trying to integrate something that isn't actually available yet.
The Data Is Open
One thing we decided early: the listing data shouldn't live only on this site.
So we put it in a public GitHub repo: Full-Vibe/ucp-ecosystem. Anyone can see it, use it, fork it, build on it. If you're building a tool that needs a list of UCP merchants or implementations, you don't have to scrape this site. Just use the data directly.
It also makes the directory more trustworthy. There's no black box. You can see exactly what we list, how we categorize things, and when entries were last verified. If something is wrong, you can open a PR.
How the Directory Is Structured
The directory organizes the UCP ecosystem into five categories:
Merchants: Stores and retailers that accept UCP checkout. This is where you go if you're building a shopping agent and need UCP-enabled endpoints to test against.
Platforms: Commerce platforms like Shopify and Google Shopping that provide native UCP support, making it easy for merchants to enable UCP without custom development.
Payment Handlers: Payment processors that support UCP's token exchange specification. Stripe, Adyen, Visa, and others who handle the actual money movement.
Developer Tools: SDKs, validators, test suites, and other tools that help developers build UCP integrations. This is probably the most useful category if you're building something.
Agent Integrations: AI agents and shopping assistants that have implemented UCP as a commerce channel.
Each listing shows its UCP status (Live, Announced, or Ecosystem participant), capabilities supported, when it was last verified, and where available, code examples.
What We've Learned Building This
A few things became clear after a couple months of tracking the ecosystem:
Shopify is the multiplier. Because Shopify built UCP support directly into the platform, enabling UCP for a Shopify merchant is a toggle in the admin panel. This means the long tail of the merchant ecosystem (independent brands, niche retailers, DTC operators) is accessible through UCP in a way that large-retailer-focused protocols can't match. The total addressable merchant count for UCP is enormous because of this.
The developer tooling is ahead of where I expected. The UCP SDKs are solid. The conformance test suite is real and useful. The specification is well-documented. This isn't vaporware infrastructure.
The ecosystem is fragmented across communication channels. Discussions happen in the UCP GitHub org, on various Discord servers, in private Slack groups, and on Twitter/X. There's no single community hub. This is one of the reasons a directory matters.
Come Help
If you're building something in the UCP ecosystem and it's not listed here, add it. The fastest path is a PR to Full-Vibe/ucp-ecosystem. Or use the submit page on the site if GitHub isn't your thing.
If something is wrong, broken, or out of date: same deal. Fix it or flag it.
UCP is still in its first few months. The ecosystem is going to look very different in six months. We'd rather this directory grow with contributions from the people actually building things than just from us watching from the outside.
PRs welcome. Always.
Read next
The story behind UCPList: why a developer side project became the most comprehensive UCP directory, and why we made all the data open source.
UCPList is the directory that helps AI agents, developers, and merchants find every piece of the UCP ecosystem in one place. Here is what we built, why, and what is in it.
Platform announcements, payment handler maturity, and agent framework integrations. Here is where the UCP ecosystem stands at mid-Q2 2026.