DevToolbox is a free collection of 15 browser-based utilities for developers and everyday users. Every tool runs entirely in your browser — no account required, no data sent to any server, no ads.
JSON Formatter & Validator — Paste raw or minified JSON to format it with indentation, or minify it to compact form. Validates syntax and reports parse errors.
Base64 Encoder / Decoder — Encode plain text or binary data to Base64, or decode Base64 strings back to plain text. Useful for JWTs, data URIs, and API payloads.
URL Encoder / Decoder — Percent-encode special characters in URLs or decode encoded strings. Essential for working with query parameters and REST APIs.
Regex Tester — Write a regular expression and test it against any string with live match highlighting. Supports all standard JavaScript regex flags.
UUID v4 Generator — Generate RFC 4122 version 4 universally unique identifiers using cryptographically secure randomness. Generate up to 100 at a time.
Markdown Previewer — Write Markdown syntax and see the rendered HTML output in real time. Supports headings, bold, italic, lists, links, code, and blockquotes.
Word Counter — Counts words, characters (with and without spaces), lines, sentences, and estimated reading time for any block of text.
Case Converter — Convert text between UPPER CASE, lower case, Title Case, Sentence case, camelCase, PascalCase, snake_case, and kebab-case.
Lorem Ipsum Generator — Generate placeholder Latin text by the word, sentence, or paragraph for use in design mockups and prototypes.
Password Generator — Create cryptographically random passwords with custom length (4–128 characters) and character sets: uppercase, lowercase, numbers, and symbols.
Color Converter — Convert colors between HEX, RGB, and HSL formats instantly. Includes a color picker and outputs ready-to-paste CSS custom properties.
Unit Converter — Convert between units of length, weight/mass, temperature, area, volume, speed, and digital storage.
Percentage Calculator — Three calculators: X% of Y, X is what % of Y, and percentage change from X to Y.
Age Calculator — Calculate the exact age between two dates in years, months, days, and total days.
Unix Timestamp Converter — Convert Unix timestamps to human-readable UTC dates and ISO 8601 strings, or convert a date back to its Unix timestamp. Shows the live current timestamp.