Developer Tools — Fast, Private, No Sign-Up
Everyday utilities engineers use — JSON, encoding, hashing, timestamps, regex — running entirely in your browser. No uploads, no server roundtrips, no tracking of your payloads.
All Developer Tools
JSON Formatter
Format, beautify, and validate JSON with syntax highlighting. Supports large files.
Base64 Encode/Decode
Encode text to Base64 or decode Base64 to text. Supports UTF-8 and images.
URL Encode/Decode
Encode or decode URLs and query parameters. Handles special characters correctly.
UUID Generator
Generate random UUID v4 strings. Bulk generate and copy with one click.
JWT Decoder
Decode JWT tokens to see header, payload, and expiry. No signup, no server.
Unix Timestamp Converter
Convert Unix timestamps to human-readable dates and vice versa.
Hash Generator
Generate cryptographic hashes of text using multiple algorithms.
Slug Generator
Convert text to URL-safe slugs. Handles Unicode, accents, and special characters.
Regex Tester
Test and debug regular expressions with live highlighting, capture groups, and flag support.
Markdown Preview
Write Markdown with live preview. Export to HTML. Supports GitHub Flavored Markdown.
HTML Minifier
Minify HTML to reduce file size and improve page load speed.
CSS Minifier
Minify CSS to reduce file size and speed up your website.
JavaScript Minifier
Minify JavaScript code to reduce file size for production.
QR Code Generator
Generate QR codes for URLs, text, WiFi, vCards, and more. Download as PNG or SVG.
Password Generator
Generate strong, secure passwords with custom length and character types.
CSV to JSON Converter
Convert CSV data to JSON format with customizable delimiters and headers.
JSON to CSV Converter
Convert JSON array to CSV format for spreadsheet import.
HTML Entity Encoder
Encode or decode HTML entities (&, <, >, and named/numeric references).
Image Compressor
Compress JPG, PNG, and WebP images in your browser. Adjust quality and see savings.
Cron Expression Builder
Build cron expressions visually and see human-readable explanations with next run times.
Why client-side matters for developer tools
Most "online" JSON formatters and JWT decoders send your data to a remote server. That's a real problem when your JSON contains API keys, customer records, or internal schemas, or when your JWT is a live production token. Pasting production secrets into a web form that routes through a third-party server is a compliance incident waiting to happen.
Every tool here runs in your browser using Web APIs. Our JSON Formatter
calls JSON.parse and JSON.stringify locally. Our JWT Decoder
base64-decodes the header and payload in-memory. Our Hash Generator uses
the Web Crypto API (crypto.subtle.digest) — the same primitive your browser already ships.
Open your network tab while you use any tool. You'll see no outbound requests for your data.
What's included
- Data formatting: JSON Formatter, CSV ↔ JSON, JSON → CSV, Markdown Preview.
- Encoding: Base64, URL encode/decode, HTML entities.
- Crypto & identifiers: MD5/SHA-1/SHA-256/SHA-512 hash, UUID v4 generator, password generator, JWT decoder.
- Regex and patterns: Regex Tester with live match highlighting, Cron Expression Builder with human-readable previews, URL slug generator.
- Time: Unix timestamp converter with auto-detect for seconds vs milliseconds.
- Minification: HTML, CSS, JS minifiers.
- QR codes and images: QR code generator, image compressor.
How we keep these tools fast
The site is statically generated with Astro and served from Cloudflare's edge. Each tool is a small React island that only hydrates when you reach the page, so the rest of the site stays HTML-only. First contentful paint on a cold cache is under 500ms on a 4G connection, and subsequent tools load from the already-cached shared runtime.
Open a tool in one keystroke
Hit Ctrl+K (or ⌘K on Mac) anywhere on the site to jump to the search. Type any tool name — we surface matches instantly. Ctrl+D toggles dark mode.