Markdown Tools
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18 free Markdown tools that run in your browser: an editor, slides, a README generator, Markdown to PDF, Word, Slack and Jira, a linter and more.
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Developer
Free Developer Tools
16 free developer tools that run in your browser: format JSON, decode JWTs, test regex, compare text and encode Base64 without sending anything to a server.
All 16 developer tools
Format & convert data
Encode & decode
- Base64 Encode and Decode Convert text or files to Base64 and back, with URL-safe output.
- URL Encode and Decode Percent-encode text for URLs, decode it, and split a URL into parts.
- HTML Entity Encoder Escape text for HTML with entities like &, or decode them.
- JWT Decoder Read a JSON Web Token’s header and claims, and check its signature.
- Number Base Converter Convert between binary, octal, decimal, hex and any base to 36.
- Text to Binary Turn text into binary, hex or decimal bytes, and back again.
Generate
Need an image as a data URI? Image to Base64 makes one, with the CSS and HTML to paste. For icons, try the Favicon Generator. Writing docs or a README? The Markdown tools have an editor with a live preview, a table generator and a linter.
Questions
Is anything I paste sent to a server?
No. Every tool runs in your browser, so tokens, keys, customer data and code stay on your device. Once the page has loaded, the tools work offline too.
Do I need an account?
No. Every developer tool is free to use without signing in, with no limits.
Why use these instead of the first result in a search?
Many online formatters and decoders send what you paste to their server, which is a real risk with API keys, JWTs and production data. These don’t, and you can check: open your browser’s network panel while using one.
Which browsers are supported?
Any current version of Chrome, Edge, Firefox or Safari, on a computer or a phone.
About
The utilities you reach for every day, in one place: format and validate JSON, convert JSON to CSV and back, compare two texts, encode and decode Base64, URLs and HTML entities, read and verify JWTs, convert number bases, generate UUIDs, passwords and hashes, convert Unix timestamps, explain cron schedules and test regular expressions.
Nothing you paste is uploaded. Every tool runs in your browser, so API keys, tokens and customer data stay on your device, and the tools keep working offline once the page has loaded. No account, no limits.
How it works
- Exact JSON. The JSON tools use their own parser instead of JSON.parse, so big numbers and key order survive exactly as written, and every mistake is reported with its line and column.
- Real diffs. The Diff Checker uses Myers’ algorithm, the same one git uses, then compares the words inside each changed line.
- Your browser’s own cryptography. JWT signatures are verified, and SHA hashes, UUIDs and passwords are made, with the Web Crypto API built into every modern browser.
- Regex that can’t hang. Patterns run in a background worker that’s stopped after two seconds, so a runaway pattern never freezes the tab.
Notes
Everything runs in your browser, so very large files are limited by your device’s memory rather than by a server. The cron tools read standard five-field cron; Quartz schedules with a seconds field aren’t supported.
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