DevToolBox
Free online developer tools — no sign-up, no installs. Just open and use.
Formatters
Encoders / Decoders
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
Web Reference
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.