This glossary defines the terms you meet when you capture web pages: headless browsers, page loading, image formats, caching, authentication and social cards. Each entry gives a short definition first, then a rendered example that shows what the term changes in a real capture.
The groups of terms
- Browsers. How a headless browser works, and what the Chrome DevTools Protocol, browser contexts and Chrome flags do.
- Loading and waiting. Hydration, lazy loading, infinite scroll and web fonts. These terms explain most blank or half-loaded captures. The wait parameters control them.
- Output. PNG, JPEG, WebP, AVIF and PDF, with quality settings and the CSS rules for printed pages. See the output options.
- Caching and delivery. Cache keys, TTLs, ETags and edge caches. The caching reference shows how RenderScreenshot applies them.
- Authentication. Bearer tokens, HMAC signatures and basic auth. See signed URLs.
- Social cards. OG images, link unfurling and oEmbed. The presets reference lists the standard sizes.
How to use the glossary
Each entry links to the docs page where the term becomes a parameter. If a term explains a problem in your captures, follow that link to fix it. If you want to see the effect yourself, get a free API key and run the example request from the entry. No credit card is needed.