Headless-browser check vs. plain HTTP request — which tests my real page?

Headless-browser check vs. plain HTTP request — which tests my real page?

Q: My HTTP monitor is green but users report a blank page. Why?

A: Because a plain HTTP request fetches the raw HTML and stops. If your site renders content with JavaScript (React, Vue, most single-page apps), the raw HTML is nearly empty — the monitor sees a 200 and a shell, never knowing the app failed to boot.

A headless-browser check actually loads the page, runs the JavaScript, and can assert that an element appeared. That's what catches a broken JS bundle, a failed API call on load, or a third-party script that hangs the render.

The tradeoff: browser checks cost much more and run less often. So use plain HTTP for static/server-rendered pages and APIs; reserve browser checks for the few JS-heavy flows that matter (login, checkout). Don't browser-check your whole site — it's expensive overkill for server-rendered content.

Got a question? Drop it in the comments.