Developer & SEO Tools

Everyday utilities for developers, marketers and site owners: test patterns, compare and convert code, generate meta tags and robots.txt, build campaign links and inspect tokens. Everything runs in your browser.

Regex Tester

Test regular expressions with live highlighting and groups.

Text Diff Checker

Compare two texts by line, word or character.

Markdown to HTML Converter

Convert Markdown to HTML with a live preview.

HTML, CSS & JS Minifier

Minify HTML, CSS and JavaScript and see the savings.

JSON to YAML Converter

Convert JSON to clean, correctly quoted YAML.

Meta Tag Generator

SEO, Open Graph and Twitter tags with a Google preview.

Open Graph Preview Generator

Preview link cards for Facebook, X and chat apps.

Robots.txt Generator

Build and test robots.txt, with AI crawler blocking.

UTM Link Builder

Add UTM campaign parameters to any URL.

JWT Decoder

Decode JWTs, read claims and verify HMAC signatures.

CSS Gradient Generator

Linear and radial CSS gradients with live preview and copy.

CSS Box Shadow Generator

Visual box-shadow editor with live preview and copy.

About our developer and SEO tools

These tools cover the small jobs that come up every day when building and promoting a website. Because they run locally, they are safe to use with private source code, tokens and unreleased pages: nothing you paste is uploaded or stored. Output is plain, copy-ready text that follows current best practice for search engines and social platforms.