I 201'd this video so I could talk through a variety of error codes, including some you may have already encountered and some you may have never seen before (and wouldn't want to). What do these codes mean? Which codes should and shouldn't worry you? Learn answers to these questions and head back to work feeling 200-dokie.
After you watch the video, please 100 to the links below and 303 code-related blog posts. You won't be 417'd.
- 100: Continue
- 200: OK
- 201: Created
- 303: See Other
- 417: Expectation Failed
Links to other status code-related blog posts:
Adam Audette: Hi everyone, Adam Audette on the RKG Blog, and today I want to talk about error codes. So, some common error codes, some less-than-common error codes, and also situations where you should be alerted as an SEO if you're monitoring this kind of stuff and how you should know, "is this something that I need to be worried about, or is this something that I can safely ignore?" So, let's first talk about some common error codes.
Everybody knows about a 200, which means the page is there and you're seeing it in your browser. A 301, a 302, and the differences there. But there are some other ones, too. There is one called the 304 Not Modified and we use that and recommend that a lot to clients in order to speed up crawling of their sites from search engines. Essentially what a 304 does is it says, "Hey, this page has not been changed since you were here last. It hasn't been modified, so you don't need to download the whole page. Your cache is already up to date so you can just pull down the header."
Now, Google has said before that this may or may not make much of a difference to them in the way that they crawl. They still may just pull the whole page down. They've said that the cycles that it takes to pull the header down versus the entire document down aren't that big and Google being a robust technical company is able to accomplish that. It might have a little bit of advantage there and I would still recommend it for them anyway. For Bing, certainly, if they're respecting 304 Not Modified and it's going to help you there, too. And it's just a good practice and part of a web standard, so we would recommend doing that.
Some other error codes, 404 is an obvious one and then there's 410. So, 404 is Not Found, 410 means Gone. So, it's a very subtle difference there. It's kind of nuanced. Not Found insinuating that maybe you should come back again and try to retrieve it because maybe it'll come back, Gone meaning gone. I don't know anything about it. I don't know if it's coming back or not. It's just gone. So, we've recommended in the past for sites with a lot of pages to go ahead and return a 410 for pages that they don't want anymore instead of a 404, but it might be something to look into depending on your situation and scenarios that you're working through.
Other codes are 500s, of course, are sort of the nasty one out there and when you get a lot of 500s, I'll talk about it in a little bit here why that can be a problem. 503 is the right one to return, Service Unavailable, for when you're doing website maintenance. So, if the site is down and you know it's down because you're doing stuff and updating it, and maybe you're pushing out a new release or something, issuing a 503 response is the right thing to do because that lets the crawlers know, hey, this isn't here, but it's telling me to come back. It's unavailable right now. You can even put a revisit after time in there and tell it when you want it to come back. So, 503 is a good practice.
Five hundreds, as I said, they're the nasty ones. You hear these referred to as 5XX a lot, and these are where basically something is broken. The database is broken or the page just isn't responding at all. There's nothing there, but a complete error. If there are hundreds of these, thousands of these, maybe it wouldn't be a big deal. If there are 10,000 of these, hundreds of thousands of these, maybe it would be a big deal. This is where the threshold is really sort of up to you as an SEO to decide if it's an issue or not. On small sites it probably is never going to be too much of an issue except that if most of your sites are returning a 500, say, you have 100 pages and 50% are returning a 500 at some point in time, I would be concerned and obviously want to escalate that.
If you're a site with 100,000 pages and 1,000 of those at any given time are returning a 500, it's something you'd want to look into, but maybe not escalate. If it's higher than that or all of a sudden you're seeing them spike and you're seeing 10%, 20%, and up of pages on your site spike, especially for large sites, complex sites, that can be a problem and that's where you're going to want to look into in some detail what's happening. We've seen where a lot of 500s are being returned to servers that it's caused problems where pages start falling out of the index, pages aren't crawled as frequently or sometimes they're not crawled again for a very long time until they're spurred to crawl again, so this can be actually a big problem.
404s, not so much in this way although if a server is incorrectly returning a 404 for a page that's actually a 200, that could be a huge problem and so we've seen that where a large site is indexed fine and crawled regularly, but it's returning the wrong status code for the page, and those pages start to fall out of the index and they don't get crawled again in rankings and traffic starts to tank.
So, the key here is just to look at your site, figure out your own barometer for the health of the site and then use those as your thresholds to say, hey, is this out of the ordinary, what kind of a percentage of the total pages are these errors that I'm seeing and really, especially, looking for the 500 errors. Those are some good tips for you to check out. We've written more about this on the blog, so check that out and I'd love to hear from you in the comments with any questions or experiences of your own. Thank you so much and see you next time. SEO safe.