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Free OnlineDeveloper Tools

JSON formatter, Base64 encoder, JWT debugger, regex tester and 64+ more. No data ever leaves your browser.

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Formatters

JSON Formatter & Validator

Format, beautify and validate JSON online. Free JSON formatter with syntax highlighting, error detection and minify support.

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Encoding

Base64 Encoder / Decoder

Encode and decode Base64 strings online. Free Base64 converter tool for developers.

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Crypto & Security

JWT Decoder & Debugger

Decode and inspect JWT tokens online. View header, payload and verify JWT signatures.

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Text

Regex Tester & Explainer

Test and debug regular expressions online. Real-time regex matching with explanation.

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Encoding

URL Encoder / Decoder

Encode and decode URLs online. Free URL encoding tool with encodeURIComponent support.

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Generators

UUID Generator

Generate random UUIDs (v4) online. Free UUID generator tool for developers.

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Generators

Password Generator

Generate strong, secure passwords online. Free random password generator.

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Crypto & Security

Hash Generator

Generate MD5, SHA-256 and SHA-512 hashes online. Free hash generator tool.

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Converters

Unix Timestamp Converter

Convert Unix timestamps to human-readable dates and vice versa. Free online timestamp tool.

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Formatters

SQL Formatter & Beautifier

Format and beautify SQL queries online. Free SQL formatter with syntax support.

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Formatters

CSS Minifier / Beautifier

Minify and beautify CSS online. Free CSS minifier and formatter tool for developers.

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Encoding

HTML Entity Encoder / Decoder

Encode and decode HTML entities online. Free HTML entity converter tool.

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Text

Markdown Previewer

Preview and render Markdown online. Free Markdown editor with live preview.

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Converters

JSON to CSV Converter

Convert JSON to CSV and CSV to JSON online. Free JSON CSV converter tool.

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Converters

YAML to JSON Converter

Convert YAML to JSON and JSON to YAML online. Free YAML JSON converter tool.

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Converters

XML to JSON Converter

Convert XML to JSON and JSON to XML online. Free XML JSON converter tool for developers.

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Converters

JSON to TypeScript

Convert JSON to TypeScript interfaces and types online. Free JSON to TypeScript converter for developers.

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Encoding

Image to Base64 Converter

Convert images to Base64 encoded strings online. Free image to Base64 converter for developers.

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Generators

QR Code Generator

Generate QR codes online. Free QR code generator with download support.

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Converters

Color Converter

Convert colors between HEX, RGB, HSL and OKLCH formats. Free color converter tool.

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Text

Text Diff Checker

Compare two texts and find differences. Free online text diff checker tool.

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CSS & Design

CSS Box Shadow Generator

Create CSS box shadows with a visual editor. Adjust offset, blur, spread, color and opacity. Support for multiple shadow layers.

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Text

JSON Diff Checker

Compare two JSON objects and find differences. Highlights added, removed and changed keys with a structural diff view.

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Converters

HTML to Markdown Converter

Convert HTML to clean Markdown instantly. Supports headings, lists, links, images, code blocks, tables and more.

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Formatters

JSON Path Tester

Test and evaluate JSONPath expressions online. Paste JSON data, write a path query and see matching results instantly.

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Text

String Case Converter

Convert strings between camelCase, snake_case, kebab-case and more. Free case converter.

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Text

Cron Expression Parser

Parse and explain cron expressions in human-readable format. Free cron parser tool.

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Converters

Number Base Converter

Convert numbers between binary, octal, decimal and hexadecimal. Free base converter.

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Generators

Lorem Ipsum Generator

Generate Lorem Ipsum placeholder text online. Free dummy text generator.

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Text

Word & Character Counter

Count words, characters, sentences and paragraphs online. Free word counter tool with reading time estimate.

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Formatters

JavaScript Minifier & Beautifier

Minify and beautify JavaScript online. Free JS minifier and formatter tool for developers.

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Formatters

HTML Formatter & Beautifier

Format, beautify and minify HTML online. Free HTML formatter tool for developers.

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Generators

URL Slug Generator

Generate SEO-friendly URL slugs from text online. Free slug generator tool for developers.

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Converters

CSV to JSON Converter

Convert CSV to JSON online. Free CSV to JSON converter tool with instant preview.

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CSS & Design

CSS Gradient Generator

Create beautiful CSS gradients with a visual editor. Generate linear, radial and conic gradients with custom colors and angles.

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CSS & Design

CSS Grid Generator

Create CSS grid layouts with a visual editor. Define rows, columns, gaps and template areas. Copy the CSS code instantly.

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Generators

Chmod Calculator

Calculate Unix file permissions with an interactive chmod calculator. Convert between symbolic and numeric (octal) notation.

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Generators

Meta Tag Generator

Generate HTML meta tags for SEO, Open Graph and Twitter Cards. Create optimized meta tags with a visual editor and Google preview.

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CSS & Design

CSS Flexbox Generator

Create CSS flexbox layouts with a visual editor. Adjust direction, wrap, justify, align and gap. Copy the CSS code instantly.

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Converters

SVG to PNG Converter

Convert SVG files to PNG images online. Choose custom dimensions, scale factor and background color. All processing happens in your browser.

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CSS & Design

HTML Table Generator

Generate HTML table code with a visual editor. Set rows, columns, headers and styling. Copy clean HTML instantly.

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Converters

Text to Binary Converter

Convert text to binary and binary to text online. Supports ASCII and UTF-8 encoding. Free binary translator for developers.

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Converters

Tailwind to CSS Converter

Convert Tailwind CSS classes to vanilla CSS. Paste utility classes and get the equivalent CSS output instantly.

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Converters

JSON Schema Generator

Generate JSON Schema from JSON data instantly. Paste your JSON and get a valid JSON Schema with types, required fields and nested object support.

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Converters

CSS to Tailwind Converter

Convert vanilla CSS to Tailwind CSS utility classes online. Paste your CSS and get the equivalent Tailwind classes instantly.

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Generators

robots.txt Generator

Generate robots.txt files for your website. Configure user agents, allow and disallow rules, crawl delay and sitemap URL.

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Converters

Pixel to REM Converter

Convert pixels to REM and REM to pixels online. Free PX to REM converter for frontend developers.

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Converters

Image Compressor

Compress images online for free. Reduce PNG, JPEG and WebP file size without losing quality. 100% client-side, no upload to server.

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Converters

Image Resizer

Resize images online for free. Change width and height of PNG, JPEG and WebP images. Maintain aspect ratio or set custom dimensions.

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Converters

Curl to Code Converter

Convert curl commands to code in JavaScript fetch, Python requests, Go, PHP and more. Free online curl converter for developers.

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Converters

HTML to JSX Converter

Convert HTML to JSX online. Transform class to className, style strings to objects, and fix self-closing tags for React components.

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Generators

Code Screenshot Generator

Create beautiful code screenshots online. Export code snippets as PNG images with syntax highlighting, custom themes and backgrounds.

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Formatters

CSS Formatter & Beautifier

Format and beautify CSS code online. Indent, organize and clean up messy CSS with customizable formatting options. Free CSS beautifier.

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Converters

SVG Optimizer

Optimize and minify SVG files online. Remove unnecessary metadata, comments and hidden elements to reduce SVG file size.

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Generators

Favicon Generator

Generate favicons from images online. Create ICO, PNG and SVG favicons in all standard sizes for your website. Free favicon maker.

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CSS & Design

CSS Animation Generator

Create CSS animations visually online. Build keyframe animations with custom timing, easing and properties. Copy the generated CSS code.

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CSS & Design

CSS Border Radius Generator

Generate CSS border-radius values visually. Create rounded corners, circles and custom shapes with a live preview. Copy the CSS code.

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Converters

Aspect Ratio Calculator

Calculate aspect ratios online. Find width, height or ratio from any two values. Common presets for video, photo and screen resolutions.

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Converters

JSON to Go Struct

Convert JSON to Go structs online. Generate Go struct definitions with proper types, json tags and nested struct support.

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Generators

Open Graph Preview

Preview how your website looks when shared on social media. Test Open Graph meta tags for Facebook, Twitter/X and LinkedIn previews.

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Text

HTTP Status Code Reference

Complete HTTP status code reference. Search and browse all HTTP response codes with descriptions, use cases and examples.

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CSS & Design

Tailwind Color Palette Generator

Generate custom Tailwind CSS color palettes. Create color scales from a base color with proper naming. Export as Tailwind config.

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Formatters

HTML Minifier

Minify HTML code online. Remove comments, whitespace and optional tags to reduce HTML file size. Free HTML minifier tool.

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Encoding

String Escape & Unescape

Escape and unescape strings online. Handle JavaScript, JSON, HTML, URL and CSV string escaping. Free string escape tool for developers.

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Crypto & Security

JWT Generator

Generate signed JWT tokens online with HS256, HS384 or HS512. Free JWT generator with custom header, payload and secret key. 100% client-side.

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Generators

Markdown Table Generator

Generate Markdown tables visually online. Add rows, columns, set alignment and paste CSV to create GitHub-ready Markdown tables instantly.

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Generators

Google SERP Preview

Preview how your page appears in Google search results. Live desktop and mobile SERP snippet preview with pixel-width title and description limits.

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Crypto & Security

Bcrypt Hash Generator & Verifier

Generate and verify bcrypt password hashes online. Adjustable cost factor from 4 to 12 rounds. Compare plaintext passwords against a bcrypt hash.

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What is codetools.run?

codetools.run is a collection of 68 free, fast developer tools that run entirely in your browser. From JSON formatting and Base64 encoding to JWT debugging and regex testing, every tool processes your data client-side, so nothing ever leaves your machine.

Built for developers who value privacy and speed. No sign-ups, no tracking, no server-side processing. Just open a tool and start working. All tools are optimized for both desktop and mobile use.

Tool Categories

Encoding

Base64 Encoder / Decoder, URL Encoder / Decoder, HTML Entity Encoder / Decoder, Image to Base64 Converter, String Escape & Unescape

Formatters

JSON Formatter & Validator, SQL Formatter & Beautifier, CSS Minifier / Beautifier, JSON Path Tester, JavaScript Minifier & Beautifier, HTML Formatter & Beautifier, CSS Formatter & Beautifier, HTML Minifier

Generators

UUID Generator, Password Generator, QR Code Generator, Lorem Ipsum Generator, URL Slug Generator, Chmod Calculator, Meta Tag Generator, robots.txt Generator, Code Screenshot Generator, Favicon Generator, Open Graph Preview, Markdown Table Generator, Google SERP Preview

Converters

Unix Timestamp Converter, JSON to CSV Converter, YAML to JSON Converter, XML to JSON Converter, JSON to TypeScript, Color Converter, HTML to Markdown Converter, Number Base Converter, CSV to JSON Converter, SVG to PNG Converter, Text to Binary Converter, Tailwind to CSS Converter, JSON Schema Generator, CSS to Tailwind Converter, Pixel to REM Converter, Image Compressor, Image Resizer, Curl to Code Converter, HTML to JSX Converter, SVG Optimizer, Aspect Ratio Calculator, JSON to Go Struct

Text

Regex Tester & Explainer, Markdown Previewer, Text Diff Checker, JSON Diff Checker, String Case Converter, Cron Expression Parser, Word & Character Counter, HTTP Status Code Reference

Crypto & Security

JWT Decoder & Debugger, Hash Generator, JWT Generator, Bcrypt Hash Generator & Verifier

CSS & Design

CSS Box Shadow Generator, CSS Gradient Generator, CSS Grid Generator, CSS Flexbox Generator, HTML Table Generator, CSS Animation Generator, CSS Border Radius Generator, Tailwind Color Palette Generator

Frequently Asked Questions

Is my data safe?

Yes. Every tool on codetools.run runs 100% in your browser. Your data is never sent to any server. We use the native Web Crypto API for hash generation and all processing happens client-side.

Are these tools really free?

Absolutely. All 68 tools are completely free to use with no limits, no sign-ups, and no premium tiers. The site is supported by ads.

Can I use these tools on mobile?

Yes. All tools are fully responsive and work on smartphones and tablets. The interface adapts to any screen size for a smooth experience.

What tools are available?

We offer 68 developer tools across 7 categories: formatters (JSON, SQL, CSS, JS, HTML), encoders/decoders (Base64, URL, HTML), generators (UUID, password, QR code, slug), converters (JSON to CSV, YAML to JSON, Tailwind to CSS, SVG to PNG), CSS and design tools (flexbox, grid, box shadow, gradient generators), text tools (regex tester, diff checker, word counter) and crypto tools (hash generator, JWT debugger).