Web & SEO
Utilities for web development and search optimisation.
HTML Entity Encoder/Decoder
Encode or decode HTML entities (named and numeric). Handles Unicode correctly. Works entirely in your browser.
Meta Tag Generator
Generate common SEO and social meta tags from user-provided information. Creates Open Graph, Twitter Card, and standard SEO meta tags.
Markdown to HTML
Convert Markdown to HTML entirely in your browser. Supports GitHub Flavored Markdown with headings, lists, links, code blocks, and tables.
Markdown Editor
Write Markdown with a live two-column preview. Converts Markdown to HTML in real-time, entirely in your browser. Features GFM support, sanitized output, copy/download, and a distraction-free editor.
HTML Previewer
Write raw HTML and preview it live in a sandboxed iframe. Real-time rendering with script isolation for safe client-side testing.
HTML to Markdown
Convert HTML to Markdown. Supports headings, lists, tables, code blocks, links, images, and more. Works entirely in your browser.
SEO Inspector
Analyze a web page for SEO best practices. Check title, meta description, headings, Open Graph, Twitter Cards, canonical, robots, and more. Runs entirely in your browser where technically possible.
robots.txt Generator
Generate valid robots.txt files with user-agent rules, allow/disallow directives, sitemap declarations, and crawl-delay. Preview, copy, and download instantly.
XML Sitemap Generator
Create valid XML sitemaps from a list of URLs. Supports lastmod, changefreq, priority. Validates URLs and escapes XML. Preview, copy, and download.
Open Graph Preview
Preview how your page will look when shared on social media. Enter title, description, image, URL, and type to see Open Graph and Twitter Card visual previews and generate tags.
HTTP Status Checker
Check HTTP status codes, response times, and redirect behavior for any URL. Includes a comprehensive status code reference. Browser CORS limitations apply.
URL Redirect Checker
Trace redirect chains for any URL. See status codes, intermediate URLs, and final destination. Identify redirect loops and long chains. Browser CORS limitations apply.
UTM URL Builder
Build UTM-tagged URLs for campaign tracking. Enter base URL and UTM parameters (source, medium, campaign, term, content). Generates properly encoded URLs.
HTTP Headers Reference & Builder
Reference for common HTTP headers and a builder to format header blocks. Covers Cache-Control, Content-Security-Policy, HSTS, CORS, Referrer-Policy, and more. Educational tool only — does not modify server responses.