Small tools that just work.
Free, no-signup utilities for people who write code. Everything runs in your browser — nothing you paste is ever sent to a server.
JSON Formatter & Validator
Paste messy JSON, get it formatted, minified, or validated instantly.
Open tool → CRON · 002Cron Expression Generator
Build and decode cron schedules in plain English.
Open tool → REGEX · 003Regex Tester
Test patterns against sample text with live match highlighting.
Open tool → CONVERT · 004JSON to CSV Converter
Flatten JSON arrays into a downloadable CSV file.
Open tool → ENCODE · 005Base64 Encode / Decode
Convert text to and from Base64 instantly, with full UTF-8.
Open tool → TIME · 006Timestamp Converter
Unix timestamp to human-readable date, and back.
Open tool → ID · 007UUID Generator
Generate random v4 UUIDs in bulk, with format options.
Open tool → URL · 008URL Encoder / Decoder
Percent-encode text for URLs, or decode it back.
Open tool → COLOR · 009Color Converter
Convert colors between HEX, RGB, and HSL, with a live preview.
Open tool →Why Fieldkit
Most "free tool" sites bury a simple conversion under trackers, forced signups, or ten seconds of interstitial ads. Fieldkit does one thing: give you a working instrument, on one page, that runs entirely in your browser. No account, no upload, no rate limit.
How it works
Every tool here is static — the JavaScript that formats your JSON or parses your cron expression runs locally on your machine. Nothing you type or paste is transmitted anywhere, which also means the tools work offline once the page has loaded.