Headless browser
A real browser engine driven programmatically with no visible window. Powerful, slow and expensive in bandwidth.
A headless browser is a full browser engine controlled by code instead of a person. Chrome, Firefox and WebKit all support this mode, driven through tools such as Playwright, Puppeteer or Selenium.
#When it earns its cost
- Content rendered by JavaScript after page load.
- Flows requiring genuine interaction — clicks, scrolling, form entry.
- Targets whose anti-bot systems require a real client-side environment.
#What it costs
| Cost | Compared with an HTTP client |
|---|---|
| Memory and CPU | Substantially higher per worker |
| Latency | Full page load rather than one request |
| Bandwidth | Often 10 to 50 times more, since every asset is fetched |
#The optimisation people miss
Block images, fonts, media and analytics at the request-interception layer. On a per-gigabyte plan this frequently cuts the bill by most of its value while leaving the rendered content intact.