Free Online Developer Tools
Fast, private developer utilities that run entirely in your browser. No server, no tracking, no data collection.
JSON Formatter
Format, minify, sort keys, and validate JSON. Syntax highlighting with line-precise error reporting.
Hash Generator
Compute MD5, SHA-1, SHA-256, SHA-512 hashes. Supports text, files, and HMAC.
UUID Generator
Generate UUID v4 and UUID v7. Bulk generation, multiple formats.
Timestamp Converter
Convert Unix timestamps to human-readable dates and back. Supports seconds and milliseconds.
Color Converter
Convert between HEX, RGB, and HSL color formats. Real-time preview and WCAG contrast checker.
URL Encoder / Decoder
Encode and decode URLs with percent-encoding. Parse any URL into protocol, host, path, and query parameters.
Base64 Encoder / Decoder
Encode text or files to Base64. Decode Base64 strings back to text. Supports URL-safe Base64 and data URIs.
Regex Tester
Test and debug regular expressions with real-time highlighting. Capture groups, replace mode, and common patterns.
Lorem Ipsum Generator
Generate placeholder text by paragraphs, sentences, or words. Classic, Hipster, and Tech variants with one-click copy.
JWT Decoder
Decode JSON Web Tokens — header, payload, and signature — with syntax highlighting. Inspect standard claims, check expiry, and verify HMAC signatures.
Diff Checker
Compare two texts and see exactly what changed. Side-by-side and unified views with character-level highlighting, line numbers, and diff statistics.
Cron Expression Generator
Build and validate cron expressions with a visual editor. See human-readable descriptions and preview the next 5 execution times instantly.
Markdown Preview Editor
Write Markdown and see the rendered HTML preview in real time. Supports GFM tables, task lists, code blocks, and all standard syntax. Copy HTML or raw Markdown.
SQL Formatter
Format, beautify, and minify SQL queries with syntax highlighting. Supports SELECT, JOIN, subqueries, CASE WHEN, and more. No server, no tracking.