Free Online Developer Tools - JSON, Base64, Hash, UUID & More

Collection of free browser-based developer tools: JSON formatter, Base64 encoder, hash generator, UUID generator, regex tester, JWT decoder, password generator. No installation needed.

12 Free Browser-Based Developer Tools

No installation, no signup, no data sent to servers. These tools run directly in your browser and are also available as REST API endpoints for programmatic access.

QR Code Generator

Generate QR codes with 6 visual styles. Custom colors, sizes up to 1000px. Download as PNG or copy as base64.

Use cases: product labels, business cards, WiFi sharing, payment links

Email Validator

Verify email addresses with syntax checks, DNS/MX record lookup, and disposable email detection. Catches typos in real-time.

Use cases: form validation, mailing list cleanup, signup flows

Hash Generator

Generate MD5, SHA-1, SHA-256, and SHA-512 hashes instantly. Useful for file integrity checks and password hashing verification.

Use cases: checksum verification, API signature generation, data integrity

Base64 Encoder/Decoder

Encode and decode Base64 strings. Handles text, binary data, and images. Essential for embedding data in URLs and APIs.

Use cases: API payloads, image embedding, JWT debugging

JSON Formatter & Validator

Pretty-print, minify, and validate JSON. Syntax highlighting and error detection with line numbers. Handles large JSON files.

Use cases: API response debugging, config file editing, data inspection

URL Encoder/Decoder

Encode special characters for URLs or decode percent-encoded strings. Handles query parameters and full URLs.

Use cases: building query strings, debugging encoded URLs, API testing

UUID Generator

Generate UUID v4 (random) identifiers. Bulk generation support. Copy to clipboard with one click.

Use cases: database primary keys, session IDs, correlation IDs

Password Generator

Generate cryptographically secure passwords. Customize length, character sets (uppercase, lowercase, numbers, symbols).

Use cases: account creation, API key generation, secure tokens

Regex Tester

Test regular expressions against sample text with real-time match highlighting. Supports JavaScript regex syntax with flags.

Use cases: pattern matching, input validation, text parsing

JWT Decoder

Decode JSON Web Tokens to inspect header, payload, and signature. Shows expiration time and all claims.

Use cases: debugging auth tokens, verifying claims, token inspection

Cron Expression Parser

Parse cron expressions into human-readable schedules. Shows next 5 run times. Supports standard 5-field cron syntax.

Use cases: scheduled task debugging, CI/CD pipeline configuration

Color Converter

Convert between HEX, RGB, and HSL color formats. Visual color preview. Copy any format to clipboard.

Use cases: CSS color conversion, design handoff, theme configuration