Speed reference: glossary, cheat sheets, checklists
Short pages to keep open while you work: the speed glossary, the marks that count as good, caching headers and checklists.
Quick answers for when you already know the topic and need the exact term, mark or header. These pages are short on purpose: tables and lists that you can scan in a minute, with a link to the full guide when you need the reasons.
Words and marks: the speed glossary explains a term from a report, and the Core Web Vitals cheat sheet lists the marks that count as good.
Settings: the Cache-Control cheat sheet and the image attributes cheat sheet.
Lists to tick: the website speed checklist and the WordPress speed checklist. Before a launch, use the speed checklist before launch.
Lighthouse: accessibility, best practices and SEO scores explained shows how the three other scores are made.
Guides in this topic 7 guides
- Website speed glossary in plain words
Plain-word definitions of the terms used in website speed work, from alt text to WOFF2, each linked to the guide that explains it in full.
- Core Web Vitals cheat sheet
One page with the three Core Web Vitals: what each measures, the good and poor marks, where the time goes, first fixes, related metrics, and which tool to use.
- Cache-Control cheat sheet
The Cache-Control values to send for each kind of file, what each directive means, pairs that get mixed up, how validation works, and commands to test it.
- Image attributes cheat sheet
Image attributes that affect speed or search: width, height, alt, srcset, sizes, loading, fetchpriority and decoding, plus how Chrome ranked a hero image.
- Accessibility, Best Practices and SEO scores explained
How Lighthouse scores accessibility, best practices and SEO: the weights, what each check looks for, which failures cost most and what a perfect score misses.
- Website speed checklist: from first test to last fix
A full checklist for a faster website in nine groups: measure, server, images, fonts, code, layout, interactions, search safety and upkeep, with pass marks.
- WordPress speed checklist
A tick-off checklist for a faster WordPress site, from Site Health and PHP to caching, plugins, images, the database and WooCommerce.
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