DevToolBox

Free online developer tools — no sign-up, no installs. Just open and use.

Formatters

JSON Formatter

Format, minify, and validate JSON with syntax highlighting.

Regex Tester

Test regular expressions against text with real-time match highlighting.

Encoders / Decoders

Base64 Encode / Decode

Encode text to Base64 or decode Base64 back to plain text.

URL Encoder / Decoder

Encode or decode URLs and query string parameters.

JWT Decoder

Decode JSON Web Tokens — view header, payload, and claims.

Converters

Timestamp Converter

Convert between Unix timestamps and human-readable dates.

Color Converter

Convert between HEX, RGB, and HSL with WCAG contrast check.

Number Base Converter

Convert between binary, octal, decimal, and hexadecimal numbers.

Case Converter

Convert text between camelCase, snake_case, kebab-case, and more.

JSON ↔ YAML

Convert JSON to YAML and YAML to JSON with one click.

Generators

UUID Generator

Generate random RFC 4122 v4 UUIDs in bulk.

Hash Generator

Compute MD5, SHA-1, SHA-256, SHA-384, and SHA-512 hashes.

QR Code Generator

Create scannable QR codes for URLs, text, or contact info.

Web Reference

Cron Expression Parser

Explain a cron expression in plain English and preview next runs.

HTTP Status Codes

Searchable reference of every HTTP status code and its meaning.

About DevToolBox

DevToolBox is a curated collection of free online utilities for software developers. Every tool runs entirely in your browser using JavaScript and Web Crypto APIs — your input never leaves your device, never touches a server, and never gets logged.

Currently featuring 15 tools across formatters, encoders, converters, generators, and reference pages. The toolbox is updated regularly with practical utilities developers reach for during day-to-day work — debugging an API response, decoding a token, generating a UUID, picking a color, or looking up an HTTP status code without leaving the keyboard.