Page Weight & HTML Code Checkers
Heavy pages and broken code slow pages down and can stop content rendering. These checkers measure what the page ships: total bytes, whether the HTML is compressed, how images are sized and loaded, and whether scripts throw errors.
Some of them load the page in a real Chromium browser, so they take a few seconds longer than the HTML-only checks.
Deprecated HTML Tags Checker
Scans for obsolete HTML elements like <center>, <font> and <marquee>.
GZIP Compression Test
Checks the HTML response is served with gzip, brotli or deflate compression.
Image Optimization Checker
Checks images declare width/height and use lazy-loading below the fold.
Inline CSS Checker
Counts elements using a style="" attribute instead of a stylesheet.
Google AMP Tester
Reports whether the page is itself an AMP page or declares an amphtml alternate.
Webpage File Size Checker
Total download size of the rendered page, broken down by resource type.
Webpage JavaScript Error Checker
Loads the page in a real browser and reports any JavaScript errors thrown.