UCP Checker vs UCPtools: Which Validator Do You Need?
UCP Checker detects whether a UCP profile exists. UCPtools validates it across four levels and tells you exactly what's wrong — with 20+ error codes, JSON paths, and fix hints. Both are free. Here's how they compare.
The Short Answer
Use UCP Checker when you need a fast yes/no answer or want to scan sites with the browser extension. Use UCPtools when you need detailed error codes, agent simulation, profile generation, security scanning, or CI/CD automation.
Feature Comparison
| Feature | UCPtools | UCP Checker |
|---|---|---|
| Validation Depth | 4-level: structural, rules, network, SDK | Basic detection: detected / not detected / partial |
| Error Reporting | 20+ error codes with JSON paths and fix hints | No error details or fix guidance |
| Agent Simulation | Full workflow: discovery, checkout, payment readiness | Not available |
| Profile Generation | Generate full profiles + Ed25519/ES256 signing keys | Not available |
| Security Scanning | Endpoint security analysis + vulnerability detection | Not available |
| Feed Analysis | Product feed validation and optimization | Not available |
| Hosting Artifacts | Nginx, Apache, Vercel, Netlify, Cloudflare, AWS configs | Not available |
| REST API | Full API for CI/CD automation | Not available |
| CLI Tools | Command-line validator and generator | Not available |
| Browser Extension | Not available | Chrome, Edge, Brave extension |
| Bulk Checking | Via API and CLI | Built-in bulk checker |
| Merchant Directory | Community directory with benchmarking | 956 monitored merchants |
| Platform Guides | Shopify, WooCommerce, Wix, Magento, BigCommerce, Squarespace | Not available |
| Pricing | Free (paid tiers for monitoring) | Free |
Detailed Comparison
Validation Depth
The biggest difference between the two tools. UCP Checker checks whether a /.well-known/ucp file exists and returns one of three statuses: Detected, Not Detected, or Partial. That's useful for a quick scan, but it won't help you fix anything.
UCPtools runs four levels of validation, each catching different categories of issues:
UCPtools
- Structural — JSON schema, required fields, version format
- Rules — Namespace/origin binding, extension chains, HTTPS enforcement
- Network — Remote schema fetching, endpoint reachability
- SDK — Official @ucp-js/sdk compliance check
UCP Checker
- Checks if /.well-known/ucp exists
- Returns: Detected / Not Detected / Partial
- No breakdown of what passed or failed
Error Reporting
When something is wrong with your UCP profile, you need to know exactly what and where. UCPtools returns 20+ specific error codes, each with the exact JSON path, severity level, and a hint explaining how to fix it.
UCPtools
- Error codes like
UCP_NS_ORIGIN_MISMATCH - JSON path:
$.ucp.capabilities[2].schema - Severity: error / warn / info
- Fix hint with each issue
UCP Checker
- No error codes
- No JSON path references
- No fix suggestions
Agent Simulation
A valid profile doesn't guarantee a working checkout. UCPtools includes an AI agent simulator that tests the full workflow an agent would follow: discovery, capability inspection, checkout simulation, and payment readiness. If an agent would fail on your store, the simulator tells you exactly where.
UCPtools
- Discovery flow testing
- Capability inspection
- Checkout simulation
- Payment readiness verification
UCP Checker
- No agent simulation
- No checkout flow testing
- Cannot verify real agent behavior
Profile Generation
If you're building a UCP implementation from scratch, UCPtools generates compliant profiles, creates Ed25519 and ES256 signing key pairs, and produces platform-specific hosting configurations for Nginx, Apache, Vercel, Netlify, Cloudflare Workers, and AWS S3+CloudFront.
UCPtools
- Full profile generation
- Minimal checkout-only profiles
- Ed25519/ES256 signing key generation
- Hosting artifacts for 6+ platforms
UCP Checker
- No profile generation
- No signing key generation
- No hosting configurations
Security and Monitoring
UCPtools scans your UCP endpoints for security vulnerabilities and analyzes product feeds for compliance issues. It also offers paid monitoring tiers with weekly automated validation and email alerts when your profile breaks.
UCPtools
- Endpoint security scanning
- Product feed analysis
- Benchmarking against merchant directory
- Automated weekly validation (paid)
- Email alerts on profile issues (paid)
UCP Checker
- AI bot visibility check (GPTBot, Gemini, etc.)
- No security scanning
- No feed analysis
- No automated monitoring
Developer Tools
UCP Checker offers a browser extension for Chrome, Edge, and Brave — useful for checking any site as you browse. UCPtools provides a REST API and CLI for integrating validation into CI/CD pipelines, build processes, and automated workflows.
UCPtools
- REST API —
POST /v1/profiles/validate - CLI tools for local validation and generation
- CI/CD integration
- PDF validation reports
UCP Checker
- Browser extension (Chrome, Edge, Brave)
- Bulk domain checker
- No API access
- No CLI
Pricing
Both tools are free for core validation. UCP Checker is entirely free with no paid tiers. UCPtools is free for all validation, simulation, and generation features, with optional paid tiers that add automated monitoring, email alerts, and managed hosting.
Which Tool Should You Use?
Choose UCP Checker If:
- You need a quick yes/no check on any domain
- You want to scan competitor sites while browsing (extension)
- You need to check many domains at once (bulk checker)
- You don't need to fix issues — just detect if UCP exists
Choose UCPtools If:
- You need to find and fix specific validation issues
- You want to test how AI agents interact with your store
- You're building a new UCP implementation from scratch
- You need signing keys, hosting configs, or platform guides
- You want API or CLI access for CI/CD automation
- You need ongoing monitoring and compliance tracking
Try UCPtools Now — Free, No Signup
Paste any domain and get a full 4-level validation report with error codes, JSON paths, and fix hints in seconds.
Frequently Asked Questions
- Is UCP Checker enough for validating my store?
UCP Checker tells you whether a UCP profile exists at your domain, but it cannot tell you what is wrong with it or how to fix it. If your profile shows as "Partial" or you need to debug specific issues, you need a tool with detailed error reporting — UCPtools provides exact JSON paths, error codes, and fix hints for every issue found.
- What does UCPtools do that UCP Checker doesn't?
UCPtools provides four levels of validation (structural, rules, network, SDK), an AI agent simulator that tests real checkout workflows, profile generation with signing keys, security scanning, product feed analysis, hosting artifacts for 6+ platforms, and a REST API and CLI for automation. UCP Checker provides a binary detection check and a browser extension.
- Can I use both UCPtools and UCP Checker?
Yes. UCP Checker is useful for quick checks — especially the browser extension for scanning competitor sites while browsing. UCPtools is the tool you use when you need to actually build, debug, and maintain a working UCP implementation. They serve different stages of the workflow.
- Which UCP validator is better for Shopify stores?
Shopify generates your UCP profile automatically, so both tools can check it. However, UCPtools provides deeper validation that catches issues the Shopify dashboard and basic checkers miss — such as namespace/origin binding errors, extension chain problems, and signing key configuration. UCPtools also has a dedicated Shopify implementation guide.
- Is UCPtools free?
Yes. UCPtools core validation, agent simulation, profile generation, and all developer tools are free. Paid tiers add monitoring features like automated weekly validation, email alerts, and managed UCP hosting for teams that need ongoing compliance tracking.
- What is the best free UCP validator in 2026?
For comprehensive validation, UCPtools is the most thorough free UCP validator available — it runs four validation levels (structural, rules, network, and SDK compliance), reports 20+ specific error codes with fix hints, and includes agent simulation. For a quick existence check or browser-based scanning, UCP Checker is a lightweight alternative with a Chrome extension.
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