# Code Testing - 9 Free Online Tools

> Test and validate code: regex patterns, JWT tokens, grammar, text diffs, math problems, and typing. Free developer tools for everyday coding tasks.

Browse all 9 free online code testing on DevTools Hub.

URL: https://tools.scoreroute.com/tools/code-testing/

## Frequently Asked Questions

**What can I test with the code testing tools?**

You can validate regular expressions against sample text, decode and verify JWT tokens (HS256/RS256), check grammar, diff two text blocks, solve math problems step-by-step, and measure typing speed. All eight tools are free, no signup.

**How does the regex tester work?**

Paste a regex and a test string; the tool highlights all matches in real time and reports capture groups, indices, and flag behavior (global, case-insensitive, multiline). Patterns execute in your browser using the JavaScript RegExp engine.

**Is the JWT decoder safe to use with real tokens?**

Yes for inspection: decoding only reads the header and payload, it does not verify the signature. Do not paste tokens containing highly sensitive claims (PII, secrets) into any third-party site; for production verification, use a library in your own backend.

**Do these tools require an account or API key?**

No. All eight code-testing tools run client-side with no server API calls and no signup. You can use them offline once the page is loaded.

## Tools in this category

- [Code Minifier & Beautifier - JS, CSS, HTML](https://tools.scoreroute.com/tools/code-minifier/): Free online code minifier and beautifier. Minify JS, CSS, HTML for production or beautify for debugging. Size stats, copy, all in browser. No signup.
- [Free Grammar Checker - AI Error Explanation](https://tools.scoreroute.com/tools/grammar-checker/): Free AI grammar checker that not only corrects your English but explains why it's wrong. Perfect for learning proper grammar rules.
- [Free Online Math Solver - Step-by-Step Solutions](https://tools.scoreroute.com/tools/math-solver/): Free online math solver with step-by-step solutions. Solve algebra, equations, fractions, and more. No signup required, instant results.
- [Free Text Diff Checker - Compare Text & Code Online](https://tools.scoreroute.com/tools/text-diff/): Free online text diff checker to compare text and code. Side-by-side view with syntax highlighting. Compare JSON, XML, code files and find differences.
- [Free Typing Test - WPM, Accuracy & Code Mode](https://tools.scoreroute.com/tools/typing-test/): Free online typing test with WPM, accuracy, and code snippet modes (JavaScript, Python, SQL, HTML). No signup. Practice common words, quotes, numbers, and programming syntax. Privacy-first.
- [HTML Playground - Live HTML CSS JS Code Editor with Preview](https://tools.scoreroute.com/tools/html-playground/): Free online HTML playground with live preview. Write and test HTML, CSS, and JavaScript instantly. No signup, 100% private browser processing. AI cannot run your code - we do.
- [JavaScript Obfuscator - Protect JS Code Online](https://tools.scoreroute.com/tools/javascript-obfuscator/): Free online JavaScript obfuscator. Protect JS source code with variable renaming, string encryption, control flow flattening, dead code injection, debug protection, and self-defending. 100% private browser, no signup. AI cannot reliably obfuscate JS - we use a deterministic engine.
- [JWT Decoder - Decode & Verify Tokens](https://tools.scoreroute.com/tools/jwt-decoder/): Free JWT decoder and token inspector. Decode JSON Web Tokens, inspect claims, verify payload data and JWT format. 100% browser-based, no signup.
- [Regex Tester - Test Regular Expressions](https://tools.scoreroute.com/tools/regex-tester/): Test regular expressions with real-time matching. Supports g, i, m, s flags. See match count and captured groups.

## About DevTools Hub

DevTools Hub is a free collection of 150+ browser-based developer tools. No signup, no tracking, all processing happens in your browser. See [llms.txt](https://tools.scoreroute.com/llms.txt) for the full tool catalog.