Developer utilities by Gary Le Sueur
Generate UUIDs, short IDs, NanoIDs, and ULIDs with one click.
Encode text to Base64 or decode Base64 back to text.
Percent-encode text for URLs or decode encoded strings.
Convert special characters to HTML entities and back.
Generate placeholder text in paragraphs, sentences, or words.
Convert between Unix timestamps and human-readable dates.
Count characters, words, sentences, lines, and bytes in your text.
Upload a square PNG and get every favicon size your site needs.
Upload a PNG and get every icon size a Chrome extension needs.
Inspect Open Graph tags and preview how your link looks on social platforms.
Pretty-print and validate JSON with clear error messages.
Decode JWT headers and payloads — no secret needed.
Convert colours between hex, RGB, and HSL with a live preview.
Generate SHA-1, SHA-256, SHA-384, and SHA-512 hashes from text.
Test regular expressions with live match highlighting and capture groups.
Compare two blocks of text and see additions and deletions highlighted.
Convert between px, rem, em, vh, and vw with configurable base values.
Spot invisible and non-printing characters hiding in your text.
Write Markdown and see a live rendered preview side by side.
Compress and resize images with adjustable quality and format.
Decode cron expressions into plain English and preview upcoming run times.
Convert SVG files to rasterised PNG or JPEG at any size.
Enter text or a URL to generate a QR code. Download as SVG or PNG.
Paste a className string and get it back sorted in the recommended Tailwind order.
Pick dimensions, colours, and overlay text — get a downloadable placeholder PNG or a data URL.
Enter a date and see it formatted in ISO 8601, RFC 2822, SQL, relative, and more.
Pick a date and time, then see it displayed across multiple time zones.
Calculate the duration between two dates, or add a duration to find an end date.
Add or subtract days, weeks, months, or business days from any date.
Find the ISO week number for a date, or look up the date range for a given week.
Paste text containing Unix timestamps and see them converted to dates inline.
Convert between decimal, hexadecimal, octal, and binary. Supports large integers.
Convert between bytes, kilobytes, megabytes, and more — in both SI and binary units.
Calculate aspect ratios from dimensions, or find a missing dimension from a ratio.
Toggle permissions or enter a number to see the chmod breakdown.
Enter CIDR notation to see the network details, host range, and subnet mask.
Paste a title or sentence to generate a URL-friendly slug.
Convert text between camelCase, PascalCase, snake_case, kebab-case, and more.
A searchable reference of all HTTP status codes with descriptions and use cases.