How a 200 response works
When a browser or a crawler asks for a URL and the server can supply it, the server answers with the code 200, followed by the page itself. It is the ordinary, uneventful answer, and it is what every working page on your site returns. You will see it written as “200 OK” in a crawl report or in your browser’s developer tools.
A 200 is a statement about the request, not about the quality of what came back. The server is saying: this address exists and here is the content for it. It is not saying the content is useful, complete, or the thing the visitor wanted. A page showing the words “sorry, nothing found” can be served with a 200, and as far as the protocol is concerned nothing is wrong.
That gap between “the request succeeded” and “the page is worth having” is where most of the trouble with this status code lives.
Why a 200 matters
It is the entry requirement for search. A URL that cannot return a 200 cannot be indexed, so before you investigate rankings, content or links, confirm the page actually answers. Every URL in your sitemap, every page in your menu and every destination at the end of a redirect should return one.
It also matters because search engines take a 200 at face value and keep the URL. A page that answers successfully will be revisited, considered for the index, and counted among the pages your site is asking to have crawled — whether or not you meant to offer it.
Common mistakes with 200 responses
The classic mistake is the friendly error page. A deleted product or an out-of-stock item shows a helpful “not found” message, but the server still answers 200, which creates a soft 404. Search engines have to guess, and they may keep visiting a URL that will never be worth anything.
The same thing happens by default in many JavaScript applications, where the server answers every route with the same shell and the “page not found” screen is drawn afterwards in the browser. The visitor sees an error; the crawler sees success.
The second mistake is confusing a 200 with permission to index. Indexing needs a successful response and no directive blocking it. A page can answer 200 perfectly and still be kept out of search by a robots meta tag, which is exactly the combination that produces “why is my new page not appearing” a month after launch.
How to act on it
Crawl the site and check that the pages you want ranked answer 200, and just as important, that pages you have removed do not. Deleted content should return a missing or gone response so it can leave the index cleanly; only redirect it if there is a genuinely equivalent page to send people to.
Then test the failure cases deliberately. Ask for a URL you know does not exist, an old product address and a mistyped path, and check the code rather than the screen. If those come back 200, the fix belongs with your developer, and it is a standard part of technical SEO work rather than anything exotic.