Discover 19 powerful and free online web utilities every developer should bookmark—tools for JSON, HTML, CSS, JS, Markdown, SQL, and more.

As a developer, efficiency is everything. Whether you're writing code, debugging, formatting, or just trying to convert data from one format to another, the right tools can save you hours. Luckily, you don’t need to download heavy software or pay for expensive licenses to get the job done. There are dozens of free online web utilities out there that can streamline your programming process—and we’ve curated 19 of the best.

These tools cover everything from Markdown conversion to code minification, beautification, obfuscation, and data format transformation for HTML, CSS, JavaScript, JSON, XML, SQL, and more. Bookmark this post—it’s a toolbox you’ll want at your fingertips.

1. Markdown to HTML Converter 

Whether you're writing documentation, blog posts, or README files, Markdown is a favorite for developers. This utility converts Markdown syntax into clean, responsive HTML code with a single click. No more manual translation—just paste and go. - (LINK)

2. HTML to Markdown Converter

Need to turn your HTML content into Markdown for easier editing or GitHub-friendly formatting? This tool reverses the conversion, stripping out inline styles and focusing on structure. - (LINK)

3. CSV to JSON Converter

Working with spreadsheets? This tool helps convert CSV files into structured JSON format—perfect for feeding APIs or databases with tabular data. - (LINK)

4. JSON to CSV Converter

On the flip side, if you have JSON data and need to view it in a table or Excel spreadsheet, this converter does the job quickly and cleanly. - (LINK)

5. JSON to XML Converter

When working with legacy systems or APIs that require XML, this tool converts your JSON data structures into XML format without manual restructuring. - (LINK)

6. XML to JSON Converter

Likewise, if you're modernizing old XML feeds or SOAP data, convert them into JSON in seconds. Great for JavaScript applications that consume APIs. - (LINK)

7. JSON Beautifier

Tired of staring at compressed or minified JSON blobs? This beautifier formats your JSON into a readable, tree-like structure that makes debugging a breeze. - (LINK)

8. JSON Validator

Syntax errors in JSON can break your app. This validator checks for structural issues, missing commas, or malformed objects, giving you instant feedback. - (LINK)

9. HTML Entity Encode

Need to safely display HTML code inside another webpage or app? This encoder converts characters like <, >, and & into their HTML-safe equivalents. - (LINK)

10. HTML Entity Decode

This utility does the opposite—convert HTML entities back into readable characters. Essential when dealing with scraped or encoded content. - (LINK)

11. HTML Tags Stripper

This tool removes all HTML tags from content, leaving just the plain text. It’s great for extracting content or cleaning up pasted HTML. - (LINK)

12. HTML Minifier

Reduce the size of your HTML files by removing whitespace, line breaks, and comments. This speeds up page load time and improves SEO performance. - (LINK)

13. CSS Minifier

Compress your CSS files without affecting functionality. Smaller stylesheets mean faster site performance, especially on mobile. - (LINK)

14. JS Minifier

Shrink your JavaScript by removing unnecessary spaces, line breaks, and comments. Ideal for deploying scripts to production environments. - (LINK)

15. HTML Formatter

If you’re handed messy or one-line HTML files, this formatter will indent and structure them into clean, readable code. - (LINK)

16. CSS Formatter

Improve the readability of your style sheets by organizing them with consistent spacing, indentation, and formatting. - (LINK)

17. JS Formatter

Beautify compressed JavaScript so it’s easier to read and debug. Great for reverse-engineering or code reviews. - (LINK)

18. JS Obfuscator

Want to protect your code from copy-paste theft? This obfuscator converts your JS into unreadable but functional code—perfect for protecting IP in public scripts. - (LINK)

19. SQL Beautifier

Working with raw SQL queries that are hard to read? This beautifier will structure your SQL statements so they're cleaner, clearer, and easier to troubleshoot. - (LINK)

💡 Why These Tools Matter

In modern development, speed and clarity are non-negotiable. These free online web utilities eliminate the need for heavy desktop apps or plugins. They work directly in your browser, they’re fast, and they often come with no limitations.

Whether you’re working on front-end HTML/CSS/JS projects, building APIs with JSON/XML, or managing data with SQL, these tools are like having a developer’s Swiss Army knife in your browser.

📌 Final Thoughts

If you’re a developer, designer, or data wrangler, there’s no reason not to use these tools. They save time, reduce stress, and keep your workflow lightning-fast. Bookmark this page, share it with your team, and keep these tools in your daily toolkit.