UA Parser

Visual email signature builder generating HTML for major email clients

Analyze keyword density for English words and Chinese bigrams for SEO

Parse URL into protocol, domain, path, query params, fragment with auto-decode

Visual robots.txt generator with one-click allow/disallow all

Generate SEO meta tags: title, description, keywords, and Open Graph

Validate, pretty-print or minify JSON with error line:col reporting

Merge multiple PDF files in sequence, all processed locally in browser

Generate cryptographically secure passwords with custom length and charset