Free Online Developer Tools

Fast, private utilities that run entirely in your browser.

DevToolbox is a collection of fast, free developer utilities that run entirely in your browser. No sign-up, no uploads, no waiting — your data never leaves your device. Pick a tool below.

Formatters & Validators

JSON FormatterStart here: beautify, minify & validate JSON

Encoders & Decoders

Base64 Encode / DecodeText ↔ Base64 with UTF-8 URL Encode / DecodePercent-encode URL parts HTML Entity Encode / DecodeEscape < > & safely JWT DecoderDecode JWT header & payload

Generators

UUID GeneratorRandom v4 UUIDs Password GeneratorStrong random passwords Hash GeneratorSHA-1 / 256 / 384 / 512 Lorem IpsumPlaceholder text Slug GeneratorClean URL slugs

Converters

Timestamp ConverterUnix epoch ↔ date Number Base ConverterBin / Oct / Dec / Hex Color ConverterHEX ↔ RGB ↔ HSL Case ConvertercamelCase, snake_case…

Text & Dev

Regex TesterTest regex & see matches Text DiffCompare two texts Word CounterWords, chars, reading time Cron ExplainerExplain a cron schedule

Ad slot (AdSense)

Why DevToolbox?

Every tool here is 100% client-side: your JSON, tokens, passwords and text are processed locally in JavaScript and never sent to a server. That makes DevToolbox fast and private — safe even for sensitive data like JWTs and API responses. Bookmark it as your everyday developer toolbox.