SEO Tech Tests
Technical SEO & Web Validation Tools
Test HTML, HTTP responses, rendering, crawler access, domain security, and other technical website signals -- one focused tool per test, run against the real response.
Popular Tools
HTML Validator
Check HTML for spec errors, accessibility problems, and SEO markup issues.
Open Tool →HTTP Status Checker
Check HTTP status codes, redirect chains, and server responses for multiple URLs.
Open Tool →User-Agent Checker
Compare HTTP responses for browser, search crawler and AI User-Agent profiles.
Open Tool →Response Stability Test
Run up to 20 sequential requests to check HTTP status, latency and response consistency.
Open Tool →Robots.txt Checker
Fetch and parse a domain's robots.txt for issues and conflicts.
Open Tool →AI Agent Readiness Checker
Check whether a website exposes the files, headers, crawler rules and emerging protocols used by AI agents.
Open Tool →Accessibility Checker
Run automated accessibility checks against a live page with axe-core.
Open Tool →Domain Security Score
One weighted 0-100 score combining malware/phishing reputation, spam/abuse, infrastructure, transport security, DNS security, registration, popularity, and authority signals.
Open Tool →Tool Categories
Domain Security Score
Runs 46 independent reputation, malware, phishing, DNS, TLS, and infrastructure checks against one domain and combines them into a single weighted 0-100 score and risk level.
Check Domain Security →HTTP & Response Debugging
See exactly what a server returned: status codes, full redirect chains, response headers, and -- where captured -- the response body itself. Compare responses across User-Agents and run repeated requests to check stability over time.
Open HTTP Status Checker →- Status codes
- Redirect chains
- Response headers
- Response body (View Response)
- User-Agent comparison
- Response stability
HTML Validation
Find markup errors and warnings using the dedicated HTML Validator, or scan a domain's key pages and group recurring HTML issues across the site with Site Scan.
Open HTML Validator →Why SEOTechTests
Focused technical tests
Individual tools for specific HTTP, HTML, crawling, and security signals -- not one do-everything form.
Inspect actual responses
Where supported, inspect the status, headers, and response body SEOTechTests actually received from the target, not just a summary.
Source-backed checks
Security and standards-based tools link to their underlying providers, datasets, and specifications.
Clear results
PASS / INFO / WARNING / FAIL / UNKNOWN outcomes, with explanations where applicable.
FAQ
What is SEOTechTests?
A collection of independent technical tools for testing HTML, HTTP behavior, crawling and bot access, domain security, and AI crawler readiness signals. Each tool runs a real check against the target and reports what it actually found.
What can I test with SEOTechTests?
HTML markup and accessibility, HTTP status codes and redirect chains, how different browsers/crawlers/AI User-Agents are treated, domain and infrastructure security signals, and technical SEO markup like robots.txt, meta tags, and AI-agent discovery files. See the full list on the All Tools page.
Are the tools free to use?
Yes. Every tool on this site is free to use without an account.
Does SEOTechTests replace a full SEO or security audit?
No. These are independent technical checks and diagnostics, meant to inform a manual review -- not a substitute for a professional security assessment or a complete SEO audit.
Need a specific test?
Explore the complete collection of technical SEO and web validation tools.
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