What a 200 OK means
The HTTP spec (the rulebook for how browsers and servers talk) says a 200 means the request was understood, accepted, and the response body holds the result. For a GET, that body is the content at the URL you asked for. For a POST, it's usually a summary of what the action did. In theory, servers should never send 200 when something went wrong — that's the job of the 4xx codes (your mistake) and 5xx codes (the server's mistake). In practice, many servers return 200 anyway and just put an error message inside the body, because that's easier than setting the correct code. Because servers follow the rules loosely, a scraper can't trust a 200 as proof of success without also checking what's actually in the body.
Why 200 isn't always success for scrapers
Bot-detection systems often answer with a 200 even when they're blocking you — serving a challenge page, a "please enable JavaScript" notice, or an empty layout instead of the real content. Your HTTP client sees status 200 and calls it a win. Your parser then runs over the wrong HTML and either crashes or quietly pulls out nothing. This is called a soft block, and it's the sneakiest failure in scraping: if you only watch status codes, you never notice it happened. Solid production scrapers check two things after every fetch: the status code AND a structural signal that the expected content is really there (a known CSS selector, a specific JSON field, or a minimum response size).
How to validate a 200 response correctly
Use three layered checks. First, confirm the status code is 200 — if it's anything else, stop here and treat it as a failure. Second, confirm the response body is at least a reasonable size — a real product page is rarely under 5KB, so a 1KB "200 OK" is almost certainly a block page. Third, confirm at least one expected element exists — for example, `soup.select_one('.product-title')` should return an element, not None. If any of the three checks fail, treat the request as failed, queue a retry with a different proxy or fingerprint, and bump a separate "soft block" counter. That separate counter lets you tell "the site is broken" apart from "we're being detected."