Processing locally — files never leave your device

Developer Tools

12 tools

Daily-use developer utilities. Format JSON, decode JWTs, test regex, generate hashes and UUIDs, convert colors, and diff text — all client-side so secrets never touch a server.

JSON Formatter

Free JSON formatter, validator, and minifier with line/column error reporting. Sensitive payloads stay on your device — nothing is sent to a server.

JWT Decoder

Free JWT decoder for inspecting header, payload, and expiry. Tokens never leave your browser — safe for production tokens containing secrets or PII.

Base64 Encoder

Base64 encoder and decoder online: convert text to Base64 or decode Base64 strings back to readable text. UTF-8 safe, instant, and free to use with no signup.

URL Encoder

URL encoder and decoder online — percent-encode URLs, query strings, and parameters or decode them back to plain text. Instant results, right in your browser.

Regex Tester

Free regex tester with live match highlighting, capture groups, and replacement preview. JavaScript flavour. All matching runs locally — no server.

Hash Generator

Hash generator online: create MD5, SHA-1, SHA-256, and SHA-512 hashes from any text instantly. Free, with all hashing done locally in your own browser.

UUID Generator

UUID generator online — create one or hundreds of version 4 UUIDs at once using cryptographically secure randomness. Free, instant, and no signup required.

Lorem Ipsum

Lorem ipsum generator: create placeholder paragraphs, sentences, or words for mockups and layouts, then copy with one click. Free, instant, and no signup.

Color Converter

Color converter online — translate colors between HEX, RGB, and HSL formats with a live picker and instant copy. Free and runs entirely in your browser.

Markdown Editor

Markdown editor with live preview — write Markdown on the left and see the rendered result instantly on the right. Free, autosaves locally, nothing uploaded.

Diff Checker

Text diff checker online: compare two blocks of text and see additions and deletions highlighted side by side. Free and private — nothing leaves your browser.

Cron Parser

Cron expression parser — paste any cron schedule to get a plain-English explanation plus its next run times. Free, instant, and works right in your browser.

A developer's everyday utility belt

Building software is full of tiny detours. You hit a 401 and need to see what's actually inside the token. An API returns a wall of minified JSON and you can't tell where the bracket nesting goes wrong. You're writing a validation rule and have to confirm a regular expression matches what you think it does. None of these is a project on its own — they're the friction between tasks — and a good set of small, instant tools keeps that friction from breaking your flow.

The tasks that fill a working day

Formatting and validating JSON before pasting it into a ticket. Decoding a JWT to check its claims and expiry while debugging auth. Encoding a string to Base64 for a header, or percent-encoding a query parameter that keeps getting mangled. Generating a UUID for a fixture or a SHA-256 of a payload to compare against a checksum. Testing a regex against a handful of sample inputs, diffing two versions of a config to spot the one changed line, or decoding a cron expression so you actually know when that job fires. These are the micro-tasks that recur dozens of times a week.

Why these inputs must never touch a server

This is the category where "runs in your browser" isn't a nicety — it's a security boundary. A JWT often carries a real session, a user's email, role claims and sometimes secrets. The JSON you're formatting may be a production API response with customer PII. A hash you're generating could be derived from a credential. Pasting any of that into a random website that posts your input to a backend is how secrets leak into logs you don't control. Every tool here does its work locally with the browser's own crypto and parsing APIs, so a token, payload or key is processed on your machine and never transmitted — safe even for production data.

Picking the right tool

Reach for the JSON formatter when structure is the problem and the JWT decoder when auth is. Use the regex tester before you trust a pattern in code, and the diff checker when two things that should be identical aren't. Encoders (Base64, URL) solve transport problems; generators (UUID, hash, lorem ipsum) solve "I need a value" problems. Keep the whole set one tab away and you'll stop context-switching to the terminal for things that take two seconds here.