Knack is an open-source utility belt for the web — converters, encoders, generators, paste, short links, and more. No accounts required for most tools.
Pretty-print, minify, and validate JSON, XML, and YAML.
Live markdown preview with syntax highlighting. Safe for untrusted content.
Convert between CSV and JSON with delimiter choice and correct quoting.
Convert HEX, RGB, HSL, and OKLCH and check WCAG AA/AAA contrast.
Encode and decode UTF-8 text to and from base64 or base64url.
Percent-encode URL components or escape HTML entities, and decode them back.
SHA-1, SHA-256, SHA-384, and SHA-512 digests computed in your browser.
Inspect JWT header, payload, and expiry. Decode only, never verified or sent.
Compare two texts line by line or word by word, unified or side by side.
Test JavaScript regular expressions with live highlighting and capture groups.
Convert Unix seconds, milliseconds, microseconds or nanoseconds to ISO 8601, UTC, and local time.
Explain a 5-field cron expression in plain English and preview the next runs.
Generate cryptographic random strings for API keys, JWT secrets, and tokens.
Generate RFC-compliant UUID v4 and v7 identifiers in your browser.
Placeholder text as paragraphs, sentences, or words. Generated in your browser.
Strong random passwords with adjustable length and character set.
Generate a QR code from any string. Download as PNG or SVG.
Share text snippets with optional expiry. Anonymous or signed-in.
Drop a file, get a short link with content-disposition download.
Convert PNG, JPEG, WebP, AVIF — your image, your browser.
See your public IP address. Nothing is logged or stored.
Tiny knack.wtf links. Optional expiry. No tracking.
Browser-local notes. No account, no server — stored only in this browser.
Encrypted note that destroys itself after the first read.
Knack