Developer

JSON formatter

Format, validate and minify JSON with precise error locations, optional key sorting and a structural summary of what the document contains.

Base64 encode/decode

Encode and decode Base64 with full Unicode support, including a URL-safe alphabet, and encode any file to Base64 without uploading it.

UUID generator

Generate RFC-compliant UUIDs in bulk, either random v4 or time-sortable v7, with formatting options and no server involvement.

Hash generator

Generate MD5, SHA-1, SHA-256, SHA-384 and SHA-512 hashes from text or any file, computed entirely on your device.

URL encoder/decoder

Percent-encode and decode URLs and query parameters, with a breakdown of any URL into its origin, path and decoded parameters.

Epoch converter

Convert Unix timestamps to human dates and back, in seconds or milliseconds, with a live clock and a relative-time readout.

JWT decoder

Decode a JSON Web Token to read its header and claims, with expiry checked and timestamps rendered as dates, all in your browser.

Colour converter

Convert between HEX, RGB and HSL, and check WCAG contrast against white and black in the same step.

UTM builder

Build correctly tagged campaign URLs, with existing UTM parameters replaced rather than duplicated and casing normalised.

Meta tag generator

Generate title, description, Open Graph and Twitter card tags with live length warnings and a search-result preview.

CSS minifier

Minify or beautify CSS with a parser that never corrupts strings, url() values or calc() expressions.

Regex tester

Test a regular expression against sample text with live highlighting, capture groups broken out, and replacement preview.

HTML encode/decode

Escape the five characters that break HTML, or decode any named or numeric entity back to plain text.

Base converter

Convert between binary, octal, decimal and hexadecimal using arbitrary-precision arithmetic, so 64-bit values stay exact.

Cron generator

Build or decode a cron expression, read it back in plain English, and see the next eight times it will actually fire.

Robots.txt generator

Build a robots.txt with multiple user-agent groups, sitemap declarations and an optional block for AI training crawlers.

Keyword density

Analyse which words and phrases dominate a piece of copy, check a specific target keyword, and see whether anything reads as overused.

SERP preview

See how a title and description will render in search results, measured by pixel width rather than character count.

Schema generator

Generate valid JSON-LD for Organization, LocalBusiness, Article, Product, FAQPage and BreadcrumbList, ready to paste into your head.