Free Developer Tools Online

JSON formatter, Base64 encoder, UUID generator, hash calculator, regex tester — all in your browser, no login needed.

✅ 79 free tools🔒 Files deleted in 2 hours⚡ Instant results📱 Works on mobile

All Developer Tools — 79 Free Tools

Format, validate, and minify JSON.

Base64 Encoder/Decoder

Encode and decode Base64 strings.

URL Encoder/Decoder

Encode and decode URL strings.

QR Code Generator

Generate QR codes from any text or URL.

Password Generator

Generate strong random passwords.

Generate MD5, SHA1, SHA256 hashes.

Pick colors and convert HEX, RGB, HSL.

Generate random UUID v4 identifiers.

Test and debug regular expressions.

Decode and inspect JWT tokens.

Timestamp Converter

Convert Unix timestamps to human dates.

Markdown to HTML

Convert Markdown to HTML.

HTML Beautifier

Beautify and format HTML code online.

Format and minify CSS stylesheets online.

Format and prettify SQL queries online.

Format and validate XML documents online.

Validate and check YAML syntax online.

Compare two texts and find differences.

Color Converter

Convert colors between HEX, RGB, and HSL.

Build cron expressions with a visual editor.

Number Base Converter

Convert between binary, octal, decimal, and hex.

Convert JSON to YAML format and vice versa.

HTML Entity Encoder

Encode and decode HTML entities online.

Random String Generator

Generate random strings, tokens, and codes.

Parse URLs into protocol, host, path, and parameters.

CSS Gradient Generator

Generate beautiful CSS gradients visually.

Box Shadow Generator

Create CSS box shadows with a visual editor.

Color Palette Generator

Generate harmonious color palettes from a base color.

Password Strength Checker

Check how strong your password is.

Minify HTML by removing whitespace and comments.

Minify CSS by removing whitespace and comments.

JavaScript Minifier

Minify JavaScript by removing whitespace and comments.

Generate signed JWT tokens with custom payload.

Convert JSON data to XML format online.

XML Sitemap Generator

Generate an XML sitemap from a list of URLs.

Robots.txt Generator

Generate a robots.txt file for your website.

Convert XML data to JSON format online.

View and explore CSV files as a formatted table.

Chmod Calculator

Calculate Unix file permission values visually.

Escape strings for JSON, HTML, and URL contexts.

Compare two JSON objects and highlight differences.

Unicode Encoder

Encode and decode Unicode escape sequences.

HTTP Status Codes

Look up HTTP status code meanings and descriptions.

Full ASCII character table with decimal, hex, and HTML codes.

Mix two colors together with adjustable ratio.

Htaccess Generator

Generate .htaccess rules for redirects and HTTPS.

Minify JSON by removing whitespace.

Text Diff Viewer

Compare two texts line by line.

Color Shades Generator

Generate light and dark shades for any hex color.

Flexbox Generator

Visually build CSS flexbox layouts with live preview.

IPv4 Subnet Calculator

Calculate subnet mask, network address, broadcast and usable hosts for any CIDR.

MIME Type Lookup

Look up MIME types for any file extension.

Color Contrast Checker

Check WCAG 2.1 color contrast ratios for accessibility.

CSS Border Radius Generator

Visually generate CSS border-radius values with live preview.

CSS Text Shadow Generator

Visually build CSS text-shadow with live preview.

Markdown Table Generator

Build and export Markdown tables visually.

CSS Grid Generator

Build CSS grid layouts visually with live preview.

JSONPath Tester

Test JSONPath expressions against JSON data.

Crontab Explainer

Explain cron expressions in plain English.

Base64 Image Encoder

Convert images to Base64 strings for embedding.

HTML Color Names

Browse all 140+ CSS named colors with hex codes.

CSS Specificity Calculator

Calculate the specificity of any CSS selector.

PX to REM Converter

Convert pixel values to REM and EM units for CSS.

Typography Scale Generator

Generate modular typography scales for design systems.

JSON to TypeScript

Generate TypeScript interfaces from JSON data.

HTML to JSX Converter

Convert HTML markup to React JSX syntax.

Meta Tag Generator

Generate complete HTML meta tags for SEO and social sharing.

CSS Animation Generator

Generate CSS keyframe animations with live preview.

.gitignore Generator

Generate .gitignore files for any tech stack.

CSS Variables Generator

Generate CSS custom properties for your design system.

HTTP Request Builder

Generate fetch, axios, cURL, and Python code for HTTP requests.

Generate complementary, triadic, and analogous color schemes.

Aspect Ratio Calculator

Calculate new dimensions while maintaining aspect ratio.

Line Height Calculator

Calculate optimal line heights for different font sizes.

Show your current public IP address fetched client-side.

Color Blindness Simulator

Simulate how a color looks for deuteranopia, protanopia, and tritanopia.

Git Branch Name Generator

Generate git branch names from ticket number and description.

Image Color Extractor

Upload an image and extract its dominant colors using the Canvas API.

CSS Unit Converter

Convert between px, em, rem, pt, vw, vh, and % CSS units.

What You Can Do with Developer Tools

✓Format and validate JSON with syntax highlighting
✓Encode and decode Base64 strings
✓URL encode and decode strings
✓Generate SHA-1, SHA-256, SHA-512 hashes
✓Create RFC 4122 compliant UUIDs
✓Test regular expressions with live matching
✓Decode JWT tokens without verification
✓Convert Unix timestamps to human-readable dates
✓Generate and preview QR codes

Who Uses Developer Tools?

🖥️

Backend Devs

Format API responses, hash passwords, generate tokens

🌐

Web Devs

Encode URLs, decode Base64 images, test regex

🔐

Security Devs

Decode JWTs, generate hashes, inspect tokens

📱

Mobile Devs

Generate QR codes, format JSON, create UUIDs

About Developer Tools

Developers spend hours doing repetitive tasks: formatting JSON, encoding strings, testing regex patterns, generating UUIDs. ToolNest puts all these utilities in one place, accessible instantly from any browser.

All developer tools run entirely client-side in your browser — your data never leaves your device, making them safe for processing sensitive tokens, credentials, or proprietary JSON structures.

Frequently Asked Questions about Developer Tools

Do developer tools send data to a server?

No. All developer tools run 100% in your browser using JavaScript. Your data never leaves your device.

Are the generated UUIDs truly unique?

Yes. UUIDs are generated using the Web Crypto API (crypto.randomUUID()) which produces cryptographically secure, RFC 4122 compliant identifiers.

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