Free Developer Tools: JSON Formatter, Base64, UUID, Password & Hash Generator

Developers constantly need quick utilities - formatting JSON, encoding strings, generating UUIDs, or hashing data. Instead of installing CLI tools or spinning up scripts, you can do it all from your browser. Our six free developer tools run entirely client-side using the Web Crypto API - your data never leaves your machine.

JSON Formatter and Validator

The JSON Formatter beautifies, minifies, and validates JSON data with syntax highlighting:

• Beautify - format minified JSON with 2 or 4 spaces for readability
• Minify - strip whitespace from formatted JSON for smaller payloads
• Validate - instantly see syntax errors with clear error messages
• Syntax highlighting - keys, strings, numbers, booleans, and null each get distinct colors

Handles inputs up to 1MB. Perfect for debugging API responses, config files, and package.json edits.

Base64 Encoder and Decoder

The Base64 Encode/Decode tool automatically detects whether your input is Base64 and shows both encoded and decoded results:

• Auto-detection - paste any text and get both the encoded and decoded versions
• Unicode support - properly handles non-ASCII characters like emojis and CJK text
• Up to 500KB - large enough for most embedded data and tokens

Useful for decoding JWT tokens, data URIs, email headers, and API payloads that use Base64 encoding.

Secure Password Generator

The Password Generator creates cryptographically secure passwords using crypto.getRandomValues():

• Length 4 to 128 - adjustable via slider
• Character options - toggle uppercase, lowercase, numbers, and symbols
• Entropy meter - shows password strength in bits with a color-coded bar
• Auto-generate - a new password appears on every setting change

Unlike many online generators that use Math.random() (which is predictable), this tool uses the browser's cryptographic random number generator - the same source your browser uses for TLS.

UUID Generator (v4)

The UUID Generator creates RFC 4122 version 4 UUIDs using crypto.randomUUID():

• Bulk generation - create up to 1,000 UUIDs at once
• Format toggle - switch between lowercase and uppercase
• Per-UUID copy - click any UUID to copy it, or use "Copy All" for the full list

Essential for seeding test databases, generating mock IDs, and creating unique keys for distributed systems.

Color Converter (HEX, RGB, HSL)

The Color Converter translates colors between the three formats every developer needs:

• HEX - the standard for CSS (#3b82f6)
• RGB - used in CSS functions and design tools (rgb(59, 130, 246))
• HSL - intuitive for adjusting hue, saturation, and lightness (hsl(217, 91%, 60%))

Includes a native color picker, a large preview swatch, and copy buttons for each format. Edit any value and all formats update in real time.

SHA Hash Generator

The Hash Generator computes four SHA hashes simultaneously using the Web Crypto API:

• SHA-1 - 160-bit, still used for git commit hashes and checksums
• SHA-256 - 256-bit, the standard for integrity checks and certificates
• SHA-384 - 384-bit, used in some TLS configurations
• SHA-512 - 512-bit, maximum security for sensitive applications

Hashes are computed as you type with a 300ms debounce. MD5 is intentionally excluded because it's cryptographically broken and not available in the Web Crypto API.

Security and Privacy

Every tool on this page runs 100% in your browser:

• No data is sent to any server - check the network tab yourself
• Passwords use crypto.getRandomValues(), not Math.random()
• UUIDs use crypto.randomUUID() with a secure fallback
• Hashes use crypto.subtle.digest() - the same API banks use
• No cookies, no tracking, no analytics on tool inputs

Bookmark these tools for quick access. They work on any device, load instantly, and never ask you to sign up. Try the JSON Formatter, Password Generator, or Hash Generator now.