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ValidateHTML VS JSONLint

Compare ValidateHTML VS JSONLint and see what are their differences

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ValidateHTML logo ValidateHTML

Free HTML, CSS, JSON & XML validator with 12 tools and instant quality scores from 0 to 100.

JSONLint logo JSONLint

JSON Lint is a web based validator and reformatter for JSON, a lightweight data-interchange format.
  • ValidateHTML HTML validation with instant quality score and detailed error list
    HTML validation with instant quality score and detailed error list //
    2026-03-24
  • ValidateHTML Open Graph checker with social media preview
    Open Graph checker with social media preview //
    2026-03-24
  • ValidateHTML 12 free developer tools in one place
    12 free developer tools in one place //
    2026-03-24
  • ValidateHTML Robots.txt analyzer with sitemap verification
    Robots.txt analyzer with sitemap verification //
    2026-03-24
  • ValidateHTML Paste code or enter a URL to validate instantly
    Paste code or enter a URL to validate instantly //
    2026-03-24

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 signup required, no usage limits, completely free.

  • JSONLint Landing page
    Landing page //
    2023-06-18

ValidateHTML

Website
validatehtml.com
$ Details
free
Release Date
2026 March
Startup details
Country
France
Employees
1 - 9
Edit details

JSONLint

Website
jsonlint.com
$ Details
-
Release Date
-
Edit details

ValidateHTML features and specs

  • HTML Validator
    Check errors, warnings, and best practices
  • CSS Validator
    Validate stylesheets and catch syntax errors
  • JSON Validator
    Validate and format JSON with error detection
  • XML Validator
    Check XML syntax and well-formedness
  • Meta Tag Checker
    Verify title, description, viewport, charset
  • Open Graph Checker
    Check OG tags with social media preview
  • Accessibility Checker
    Detect WCAG and accessibility issues
  • Robots.txt Checker
    Analyze crawl rules and verify sitemaps
  • HTML Formatter
    Beautify or minify HTML code
  • Quality Score
    Grade from 0 to 100 with A-F rating
  • Export PDF
    Download validation reports as PDF
  • No Signup Required
    100% free, no account needed

JSONLint features and specs

  • User-Friendly Interface
    JSONLint offers a simple and intuitive web interface that makes it easy to validate JSON data without the need for advanced technical skills.
  • Error Highlighting
    The tool highlights exactly where the errors are in the JSON data, making it easier to identify and correct mistakes quickly.
  • Free to Use
    JSONLint is freely accessible to anyone with an internet connection, making it a cost-effective solution for validating JSON data.
  • JSON Formatter
    In addition to validating JSON, JSONLint also offers functionality to format and beautify JSON data, improving readability.
  • Quick Processing
    The tool processes JSON data quickly, providing almost instant feedback which is useful during development and debugging.

Possible disadvantages of JSONLint

  • Internet Connection Required
    JSONLint is a web-based tool, so it requires an active internet connection to function, which can be a limitation in offline environments.
  • Basic Features
    While JSONLint is excellent for simple validation and formatting, it lacks more advanced features like schema validation or integration with development environments.
  • No API
    JSONLint does not offer an API for programmatic access, limiting its use in automated workflows and larger development pipelines.
  • Ads on the Website
    The website includes advertisements, which can be distracting for users and might affect the user experience.
  • Limited Customization
    The tool does not offer much in terms of customization options for how errors are displayed or how JSON is formatted, which might not meet all user needs.

Analysis of ValidateHTML

Overall verdict

  • ValidateHTML.com appears to be a lightweight, browser-based HTML validation tool that helps developers quickly check their markup for syntax errors and standards compliance without needing to install software or use complex configurations. It's a practical utility for basic validation needs, though it may lack the depth of features found in more established validators like the W3C Markup Validation Service.

Why this product is good

  • Provides quick and easy HTML validation directly in the browser
  • No installation or setup required, making it accessible for quick checks
  • Helps identify syntax errors and potential issues in HTML code
  • Free to use for basic validation tasks
  • Simple interface that's easy to navigate for users of all skill levels

Recommended for

  • Beginner web developers learning HTML syntax and best practices
  • Developers needing quick, on-the-fly validation without switching tools
  • Students working on web development coursework or projects
  • Freelancers or small teams without access to premium validation suites
  • Anyone troubleshooting basic HTML rendering issues

Analysis of JSONLint

Overall verdict

  • Yes, JSONLint is a good tool for validating and formatting JSON. It is reliable, easy to use, and widely recommended by developers for ensuring the correctness and readability of JSON data.

Why this product is good

  • JSONLint is considered good because it provides a simple and effective way to validate and format JSON data, helping developers quickly identify and correct errors in their JSON structures. Its user-friendly interface and straightforward functionality make it accessible to both beginners and experienced developers.

Recommended for

  • Developers working with JSON
  • Web developers
  • API developers
  • Anyone needing to validate JSON data

Category Popularity

0-100% (relative to ValidateHTML and JSONLint)

ValidateHTML

JSONLint

Developer Tools
3 3%
Developer Tools
97% 97
Code Quality
100 100%
Code Quality
0% 0
Development
0 0%
Development
100% 100
Webdev
100 100%
Webdev
0% 0

Questions & Answers

As answered by people managing ValidateHTML and JSONLint.

What makes your product unique?

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.

Why should a person choose your product over its competitors?

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.

How would you describe the primary audience of your product?

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.

What's the story behind your product?

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.

Which are the primary technologies used for building your product?

ValidateHTML's answer

Next.js, React, TypeScript, Tailwind CSS, deployed on Vercel.

Who are some of the biggest customers of your product?

ValidateHTML's answer

Independent web developers, Freelance frontend engineers and Small web agencies.

User comments

Share your experience with using ValidateHTML and JSONLint. For example, how are they different and which one is better?
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Social recommendations and mentions

Based on our record, JSONLint seems to be more popular. It has been mentiond 138 times since March 2021. We are tracking product recommendations and mentions on various public social media platforms and blogs. They can help you identify which product is more popular and what people think of it.

ValidateHTML mentions (0)

We have not tracked any mentions of ValidateHTML yet. Tracking of ValidateHTML recommendations started around Mar 2026.

JSONLint mentions (138)

  • I Finally Built a Mac App (After Years of Someday)
    I've been maintaining jsonlint.com for years. It's a simple JSON validator that I enjoy hacking on every now and then. Nothing fancy, just a useful tool that developers seem to appreciate. - Source: dev.to / 7 months ago
  • # Complete Guide to RAG Evaluations in Amazon Bedrock
    Note: It is crucial that your batchinput.jsonl file is correctly formatted. You can use online JSON formatters and validators like jsonformatter.org or jsonlint.com to verify its integrity before proceeding. - Source: dev.to / 11 months ago
  • From Readable to Lightweight: Understanding JSON Minification
    Online Tools: Websites like JSONLint or jsonformatter.org let you paste JSON and get a minified version instantly. - Source: dev.to / 12 months ago
  • How to Store Multi-Line Strings in JSON
    Or paste your JSON into JSONLint. Both tools immediately identify stray control characters. - Source: dev.to / over 1 year ago
  • Chapter 1: setup, CSS, version control and SASS
    Our old pal VS Code will probably throw up some wiggly red lines if we do it wrong, so look out for them. If you're struggling to see why it doesn't work, try an online JSON Validator and see if it pushes you in the right direction. - Source: dev.to / over 1 year ago
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What are some alternatives?

When comparing ValidateHTML and JSONLint, you can also consider the following products

W3C Markup Validation Service - Validates HTML markup of web pages, one at a time.

JSONFormatter.org - Online JSON Formatter and JSON Validator will format JSON data, and helps to validate, convert JSON to XML, JSON to CSV. Save and Share JSON

Json List - 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.

JSON Formatter & Validator - The JSON Formatter was created to help with debugging.

Code Beautify JSON Validator - Code Beauty’s JSON Validator or JSON Lint is easy to use tool to copy, paste and validate JSON data.

JSON Editor Online - View, edit and format JSON online

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