Tools
Open a card for a full guide and a browser-only tool — no uploads, no server round trips. Curated external picks sit below.
In-browser tools
4 live · runs in your tabHTML entity encode & decode
Escape text for HTML or decode common entities — client-side only.
Meta description length
Count characters and aim for a snippet-friendly range.
URL encode & decode
Percent-encode query values or decode escaped strings.
URL slug generator
Turn titles into clean path segments for blogs and static routes.
External picks
7 curated · opens in a new tabBing URL Inspection
See how Bing crawls and indexes a URL.
Can I use
Browser support tables for HTML, CSS, and JavaScript features.
Google Search Console
Coverage, indexing issues, and Core Web Vitals for properties you verify.
Rich Results Test
Validate structured data Google can use for rich results.
Schema Markup Validator
Schema.org validation for JSON-LD, Microdata, and RDFa.
W3C CSS Validator
Check CSS for errors and warnings.
W3C Markup Validator
Validate HTML documents for syntax and parse errors.
What “in-browser” means
Every built-in tool runs in your tab — no payload leaves your browser, no analytics tracks what you paste. Hashes use the Web Crypto API, JSON parses with the engine’s native parser, and tokens are decoded with atob plus a TextDecoder. We mention what each tool does not verify on its own page.