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.
Password Generator
Generate strong, cryptographically random passwords and passphrases. Strength meter, bulk generation, exclude ambiguous characters. No server, no tracking.
Number Base Converter
Convert between binary, octal, decimal, and hexadecimal instantly. Supports any base 2–36, arbitrarily large numbers, grouped display, and step-by-step explanations.
Text Case Converter
Convert text between camelCase, PascalCase, snake_case, kebab-case, CONSTANT_CASE, Title Case, URL slugs, and more. Live stats and one-click copy.
JSON ↔ CSV Converter
Convert JSON arrays to CSV files and CSV data back to JSON. Supports nested object flattening, custom delimiters (comma, tab, semicolon, pipe), quoted fields, and table preview.
HTML Entity Encoder / Decoder
Encode special characters to named, numeric, or hex HTML entities and decode them back. Supports 200+ named entities, non-ASCII encoding, and a built-in entity reference table.
CSS Unit Converter
Convert between CSS units — px, rem, em, vh, vw, pt, cm, mm, in, vmin, vmax, ch, ex, and %. Set base font size and viewport dimensions for accurate context-aware conversions.
Epoch & Unix Timestamp Converter
Convert epoch/Unix timestamps to human-readable dates and back. Auto-detect seconds vs milliseconds, batch convert multiple timestamps, relative time, and timezone selector.
YAML ↔ JSON Converter
Convert between YAML and JSON formats instantly. Custom YAML parser with nested objects, arrays, multi-line strings, type coercion, and key sorting. All in your browser.