HTML validation is an Astrina tool for SEO and search visibility. Structural errors against W3C rules. It fetches the target page from our servers and returns results in a few seconds.
How to use HTML validation
- Enter the URL you want to analyse.
- Click "Run the check."
- Review the results — each item is explained.
- Fix any issues and re-run to confirm.
What HTML validation is used for
Professionals working in SEO and search visibility use this tool to save time and catch errors before they become problems. Common use cases:
- Auditing and quality checks in SEO and search visibility
- Validating or converting output before deploying
- Debugging issues quickly without switching between multiple tools
- Generating boilerplate output to speed up development
Key features
- Fast: server-side analysis in seconds
- Free for most use cases — no account required for the majority of checks
- Accurate: uses the same techniques as professional SEO and security scanners
- Privacy-friendly: we do not store the content we analyse beyond the session
About this tool
This is part of Astrina's suite of 24 SEO and search visibility tools. All tools are available at astrina.io/utilities.
Frequently asked questions
Is HTML validation free?
The tool is free to use for basic runs. Daily limits apply for server-side tools without an account; a free account raises those limits.
Do I need an Astrina account?
For most checks, no account is needed. An account is required for higher usage limits or paid features.
Can I use HTML validation through the API?
Yes. This tool is available through the Astrina REST API with your API key. See /api/ for documentation.
How accurate is HTML validation?
The tool uses the same techniques as professional SEO and security scanners. Results reflect what search engines and browsers actually see.
Try the HTML validation now — no account required for most checks, and the result is ready in seconds.
