
W3C Markup Validation Service
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Code Beautify JSON Validator
Nibbler
HTML Validator is a Mozilla extension that adds HTML validation inside Firefox and Mozilla.

W3C Markup Validation Service
Json List
Code Beautify JSON Validator
Schema Validator
Total Validator
Free HTML, CSS, JSON & XML validator with 12 tools and instant quality scores from 0 to 100.

Which is more popular?
Website, pricing, platforms and company facts side by side.
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| Website | users.skynet.be | validatehtml.com |
| Pricing | — | |
| Company | — | Startup from France · 1 - 9 employees · 2026 |
| Listed in |
In their own words, as submitted to SaaSHub.


No description of HTML Validator yet.
ValidateHTML is a free suite of 12 web validation tools in one place. Paste code or enter a URL to validate HTML, CSS, JSON, XML, check meta tags, Open Graph data, accessibility, robots.txt, and more. Every validation returns a quality score from 0 to 100 so you know exactly where you stand. No...
What each product offers, as listed by its team.


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How often each product is chosen within a category, 0–100% relative to the other.


As answered by people managing HTML Validator and ValidateHTML.
ValidateHTML's answer:
12 validation tools in one place with an instant quality score from 0 to 100. No signup, no limits, completely free. Paste code or enter a URL and get results in seconds.
ValidateHTML's answer:
Instead of opening 5 different tabs (W3C for HTML, JSONLint for JSON, separate tools for meta tags, Open Graph, accessibility), ValidateHTML combines everything in one interface. Plus you get a quality score that tells you exactly where you stand.
ValidateHTML's answer:
Web developers, frontend engineers, and SEO specialists who need to validate code quality before deploying. Also useful for freelancers and agencies managing multiple client sites.
ValidateHTML's answer:
I was tired of opening 5 or 6 different tabs every time I needed to validate my code before deploying. W3C for HTML, JSONLint for JSON, random sites for meta tags. So I built one tool that does everything, with a quality score to instantly know where you stand.
ValidateHTML's answer:
Next.js, React, TypeScript, Tailwind CSS, deployed on Vercel.
ValidateHTML's answer:
Independent web developers, Freelance frontend engineers and Small web agencies.
Share your experience with using HTML Validator and ValidateHTML. For example, how are they different and which one is better?
When comparing HTML Validator and ValidateHTML, you can also consider the following products.

Validates HTML markup of web pages, one at a time.
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Json List is a lightweight tool for viewing and managing JSON data. Open any local JSON file or load one from a URL, then explore it in a clean, user-friendly list format.
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Total Validator can check your website to help ensure that it is accessible, uses valid HTML and CSS, has no broken links, and is free from spelling mistakes.
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Code Beauty’s JSON Validator or JSON Lint is easy to use tool to copy, paste and validate JSON data.
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Scrutiny for Mac helps you manage and improve any number of websites. Link check, search, full website spell check, XML sitemap generator, SEO audit
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Free schema markup validator for JSON-LD and Schema.org structured data. Validate schema markup for Google Rich Results compliance. Online schema validator tool.
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