- Headless Chromium
- Google Chrome's rendering engine running without a visible UI window, used here on the server to render pages and capture pixels programmatically.
- Playwright
- Microsoft's browser automation library that drives Chromium, Firefox, and WebKit headlessly with a unified API; the primary engine for this tool.
- Puppeteer
- Google's earlier browser automation library, also driving headless Chromium; used as a fallback when Playwright is unavailable.
- Viewport
- The visible browser window dimensions in CSS pixels; the screenshot's width and height when full-page mode is off.
- Full-page capture
- A screenshot of the entire scrollable page from top to bottom, achieved by virtually scrolling and stitching slices together.
- networkidle
- A Playwright/Puppeteer wait condition that resolves when there have been no network connections for 500 ms — ensures async content finishes loading before capture.
- PNG (Portable Network Graphics)
- A lossless raster format ideal for screenshots with sharp text, UI elements, and solid colours; larger files than JPG.
- JPG (JPEG)
- A lossy raster format that compresses photos and gradients efficiently but introduces artifacts in text-heavy screenshots.
- Device pixel ratio (DPR)
- The ratio of physical to CSS pixels — Retina displays have DPR 2 or 3. The default capture uses DPR 1 unless otherwise configured.