Comparing UCP Validation Tools in 2026: Which One Should You Use?

TL;DR

Five UCP validation tools exist today. Here's the quick version:

If you want the short answer: start with UCPtools. It covers everything the others do and goes deeper. Read on for the full breakdown.

Why UCP Validation Matters Now

Google AI Mode and the Gemini App can now browse, compare, and buy products on behalf of users. The protocol powering this is UCP — the Universal Commerce Protocol - and the only way AI agents discover your store is through a valid profile at /.well-known/ucp.

If that file is missing, malformed, or incomplete, your store is invisible to AI shopping agents. No discovery. No checkout. No sales from this channel.

The problem is that UCP profiles are deceptively complex. A valid profile needs:

• Correct JSON structure with version, services, capabilities, and payment handlers
• HTTPS endpoints with no trailing slashes
• Namespace/origin binding (schema URLs must match your domain authority)
• Extension chains with valid parent capabilities
• JWK signing keys for webhook verification
• Transport bindings (REST, MCP, A2A, or Embedded)

Getting all of this right manually is tedious. Validation tools catch what you miss.

Here's what's available today.

1. Google's Official Resources

URL: developers.google.com/merchant/ucp

Google co-created UCP with Shopify and maintains the official specification, developer guides, and code samples. Google Merchant Center is where you connect your UCP-enabled store to Google AI Mode. The official spec site also has a playground for stepping through example payloads.

What it does well:

• Authoritative spec source - start here to understand the protocol
• Merchant Center integration for going live with Google AI Mode
• Code samples in Python with official SDK

What it doesn't do:

• No production validator - you can't point it at your domain and get a report
• No scoring, error hints, or simulation of real agent behavior
• The playground is educational, not diagnostic

Bottom line: Essential reading. But once you've built your profile, you need a real validator to test it.

2. Shopify UCP Dashboard

Shopify has native UCP support built into its platform. The dashboard lets Shopify merchants view their generated profile and track basic validation status.

What it does well:

• Zero configuration - Shopify generates your UCP profile automatically
• Integrated with your product data and checkout settings

What it doesn't do:

• Shopify-only - not an option for WooCommerce, Wix, Magento, or custom stacks
• Limited to what Shopify generates - can't validate custom profiles
• No detailed error codes, no agent simulation, no security scanning

Bottom line: Useful as a status indicator if you're on Shopify. But even Shopify merchants benefit from running their domain through a deeper validator to catch issues the dashboard doesn't surface.

3. UCP Checker

URL: ucpchecker.com

UCP Checker is a lightweight tool that gives you one of three results: UCP Detected, Not Detected, or Partial/Incomplete.

What it does well:

• Fast - enter a URL, get an instant answer
• Also offers a browser extension for checking sites as you browse

What it doesn't do:

• Binary result only - you know if UCP exists, but not what's wrong with it
• No error codes, JSON paths, or fix suggestions
• No simulation of how an agent would interact with your store
• No profile generation or security scanning

Bottom line: Fine for a quick "is it there?" check. But if it says "Partial," you're left with no guidance on what to fix. You'll need a deeper tool for that.

4. WebsiteAIScore

URL: websiteaiscore.com

WebsiteAIScore takes a broader approach, scoring your website's overall AI readiness - Schema.org markup, merchant return policies, structured data quality, and UCP compliance together.

What it does well:

• Broader scope - covers Schema.org, Google Shopping, and UCP in one report

What it doesn't do:

• UCP validation is one component of a larger tool - less depth on UCP-specific issues
• No agent simulation or checkout flow testing
• No detailed UCP error codes or JSON path references
• Freemium pricing model

Bottom line: If you need a general AI readiness audit, it covers more ground. But for UCP-specific validation, the depth isn't there.

5. UCPtools

URL: ucptools.dev

UCPtools is a comprehensive UCP toolkit built specifically for deep validation, agent simulation, and profile generation. Validation runs at four levels - structural, rules, network, and SDK - each catching different categories of issues.

The agent simulator tests real-world workflows: discovery, capability inspection, checkout simulation, and payment readiness. If an AI agent would fail on your store, the simulator tells you exactly why and where.

It also generates profiles from scratch, creates platform-specific hosting artifacts (Nginx, Apache, Vercel, Netlify, Cloudflare, AWS), generates Ed25519/ES256 signing key pairs, scans endpoints for security issues, analyzes product feeds, and benchmarks your profile against the merchant directory.

What it does well:

• Deepest validation available - four levels with 20+ specific error codes
• Every error includes the exact JSON path, severity level, and a fix hint
• Agent simulator tests real workflows, not just static JSON
• Profile generator + signing key generation for new implementations
• Hosting artifacts for 6+ platforms - deploy correctly on the first try
• Security scanning, feed analysis, benchmarking
• REST API and CLI for CI/CD automation
• Free

Limitations:

• More detailed than a simple yes/no check (that's the point)
• Agent simulation requires a live, accessible endpoint

Bottom line: This is the tool you use when you actually need to ship a working UCP implementation. From first draft to production validation.

Feature Comparison

Which Tool Should You Use?

"I need to validate my UCP profile."
Use UCPtools. Four validation levels, specific error codes with JSON paths, fix hints for every issue. This is the most thorough option available.

"I'm building a new UCP implementation from scratch."
Start with Google's official docs to understand the spec. Then use UCPtools to generate your profile, create signing keys, get hosting artifacts for your platform, and validate everything before going live.

"I'm on Shopify."
Your UCP profile is already generated - check the Shopify dashboard for basic status. Then run your domain through UCPtools for a full validation report and agent simulation to catch what the dashboard doesn't.

"I just want to know if a site has UCP."
UCP Checker gives a quick yes/no. But if you need to know what's wrong, you'll end up at UCPtools anyway.

"I want a broader AI readiness audit."
WebsiteAIScore covers Schema.org and Google Shopping alongside UCP. For the UCP-specific portion, pair it with UCPtools for the actual depth.

What Detailed Validation Looks Like

A simple pass/fail tells you something is wrong. A detailed validation report tells you what, where, and how to fix it:

{
  "severity": "error",
  "code": "UCP_NS_ORIGIN_MISMATCH",
  "path": "$.ucp.capabilities[2].schema",
  "message": "Schema URL origin 'otherdomain.com' does not match namespace authority 'mystore.com'",
  "hint": "Ensure schema URLs are hosted on the same domain as your namespace, or use official dev.ucp.* schemas from ucp.dev"
}

This is the difference between knowing your profile has a problem and knowing exactly which field, on which line, needs what change. When you're debugging a complex profile with multiple capabilities, extensions, and transport bindings, this level of detail saves hours.

The Landscape is Young

UCP was announced in January 2026 - barely a month ago. The tooling ecosystem is still forming. What matters now is that your profile validates correctly before AI agents start routing real shopping traffic.

The tools above cover the spectrum from quick checks to comprehensive testing. For most teams, UCPtools is the place to start — validate your profile, simulate the agent flow, and fix what's broken before it costs you sales.

Resources

• UCPtools Validator - Full validation, simulation, and generation
• UCP Specification - The official protocol spec
• Google UCP Developer Guide — Official docs and Merchant Center setup

Which tool are you using for UCP validation? Have you found issues that one tool catches but another misses? Drop a comment!

UCPtools is an independent community tool for validating and generating UCP profiles. UCP is an open standard developed by Google, Shopify, and 25+ partners.