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Test and debug regular expressions with live highlighting
Format, validate, and beautify JSON data
Build cron expressions with visual editor
Encode and decode Base64 strings and files
Encode and decode URLs and query strings
Decode and inspect JSON Web Tokens
Generate random UUIDs and validate existing ones
Generate MD5, SHA-1, SHA-256, SHA-512 hashes
Convert Unix timestamps to readable dates
Compare two texts and highlight the differences
Convert between HEX, RGB, HSL, and CMYK
Write and preview Markdown in real-time
Encode and decode HTML entities
Generate placeholder text for designs
Convert between YAML and JSON formats
Format and beautify SQL queries
Format and validate XML documents
Convert between CSV and JSON formats
Validate and explain cron expressions
Format and validate TOML files
Minify HTML, CSS, and JavaScript
Generate QR codes for URLs and text
Generate strong, secure random passwords
Count words, characters, and reading time
Convert between camelCase, snake_case, and more
Convert images to Base64 data URIs
Convert between binary, octal, decimal, and hex
Convert JSON arrays to CSV and back
Generate TypeScript types from JSON
Beautify and format JavaScript code
Convert cURL commands to code in any language
Convert text to SEO-friendly URL slugs
Escape strings for JSON, HTML, URL, SQL, and more
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Practical guides and workflows for your daily developer tasks.
A practical guide to hashing algorithms for developers — SHA-256, MD5, SHA-1, SHA-512. When to use them, when not to, and how an online hash generator speeds up your workflow.
After debugging my third XSS vulnerability caused by improper escaping, I finally sat down and learned the rules properly. Here is my complete guide to escaping strings for JSON, HTML, URLs, and more - with the gotchas that bit me.
I used to ignore URL slugs until I saw the click-through rate difference between /post?id=12345 and /how-to-write-better-code. Now I obsess over them. Here is what I have learned about slugs, SEO, and why every character matters.
camelCase, snake_case, kebab-case - why do we have so many? Here's what I've learned about naming conventions, when to use each style, and why consistency matters more than the 'right' choice.
Whether you're writing documentation, blog posts, or commit messages, word count affects readability and SEO. Here's what I've learned about optimal content length for different platforms.
After years of managing passwords for client projects at Šikulovi s.r.o., I've learned the hard way that 'clever' passwords are actually the weakest. A client account breach in 2018 taught me why truly random passwords matter.
CodeUtil is a complete collection of free online developer tools designed to streamline your daily coding workflow. Whether you're debugging JSON responses, testing regular expressions, or converting data formats like YAML and CSV, CodeUtil provides instant, browser-based solutions.
Every tool runs entirely in your browser using JavaScript—your sensitive code, API keys, and data never leave your machine. No backend processing, no data storage, no tracking.
Developers trust CodeUtil because it solves a fundamental problem: the need for quick, reliable utilities without installation, account creation, or privacy concerns.
When you decode a JWT with production credentials, format JSON with sensitive API responses, or generate hashes for verification, that data exists only in your browser's memory. Once you close the tab, it's gone. No logs, no analytics on your input, no server-side exposure.
Using CodeUtil is straightforward—no account, no installation. Browse the tools above, click any card to open it, paste your data, and see results immediately. Each tool has a clean interface with keyboard shortcuts for power users. Check out our developer blog for guides and tips, or read our FAQ for common questions.