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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
Practical guides and workflows for your daily developer tasks.
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.
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 manually write TypeScript interfaces for every API response. After the third time I mistyped a property name, I automated it. Here's why you should too.
Ever tried to debug minified production code? I have. It's like reading a novel with no spaces or punctuation. Here's how code beautification saves hours of debugging time.
You've tested your API with cURL or copied a request from DevTools. Now you need to write actual code. Here's why manual translation is error-prone and how to automate it.
At Šikulovi s.r.o., we base64-encoded every icon on a client's landing page. Page load time doubled. Here's what that disaster taught me about when embedding actually makes sense.
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CodeUtil is a comprehensive 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.