Server Headers 101 (Infographic)

For newbies in the business of crafting websites, the purpose and technicality behind server header responses can often be a little mind baffling to get to grips with. Although there are essentially so much to learn, only a few are common and essential to web professionals and the average user.

So what is a server header response, anyway? Well, let’s shed some light on them by delving deep into the most common server header responses.

Click here to enlarge.

Infographic by Builtvisible, a digital marketing agency that specializes in building brands through search and content creation.

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About the Author

Oli Archibald is a search consultant and blog writer at SEOgadget. Follow them via Twitter as @SEOgadget for plenty of great articles on SEO, Excel, Microformats, and technology in general.

This was published on Apr 18, 2011


Peter Joseph Apr 18 2011

I’ve never really bothered with this stuff and just gone along with it, but this infographic made it much more clear, thanks :)

Prasad Apr 18 2011

Wow! That’s a sweet explanation :)

Alessandro Pucci Apr 18 2011

The Super Mario 404 error page is awesome :)

Jatin Apr 18 2011

Nice way to make someone understand server headers.

Great Article.

Martín Apr 18 2011

Great infography SR!. I always learn something new reading this blog and today i decided to post a comment ;) Best regards from Argentina.

Sam Canada Apr 18 2011

Clear and easy to understand for anyone that is looking to demystified the most commons HTTP headers. Web pro’ should all know that by heart tho’ ;-)

Bad Request is HTTP error 400, not 404

I prefer the 404 page at

Michael Tuck Apr 18 2011

Nice job. Bookmarked and referenced. Will be fun to print out and post on the wall at some future time. This is good for a classroom as well as an office or cubby.

Newbie Apr 19 2011

Thank you..

505 human error?

This infographic is really good. Design is amazing. Up until now, I have only accounted for 404 page errors, but I will have to look into 301 and redirects too

Korwin Apr 19 2011

Great explanation ;)

Dustin Montgomery Apr 19 2011

Like Nils said, the graphic displays 404 instead of 400 for the Bad Request.

Entertaining though!

Richard Apr 20 2011

Thanks all for spotting the error – a 404 is a page not found, not a bad request. My bad! I think you can look at something for too long and start missing things like this :-)

Thanks for all the nice comments, glad you found this useful.

Mark Nottingham Apr 25 2011


HTTP/0.9 didn’t have status codes nor headers; the response was simply the HTML. Status codes and response headers came with HTTP/1.0, defined in RFC1945.

Also, a better name for this would be “HTTP Response Status Codes” or something similar, since it doesn’t go into detail on the headers themselves.


kitz dunphy Apr 27 2011

I really like that straightforward way of explaining header responses. Would make a useful learning resource. And looks like a cool version of the London tube map :)

Daniel Fisher Apr 27 2011

Nice – but Bad Request is 400 NOT 404 :-)

Richard Apr 27 2011

Thanks Mark – very useful feedback and apologies for the http version error!

Richard Apr 28 2011

You might also see “307 Temporary Redirect”. It’s not as common as 301 or 302, but it does come up occasionally.

Ivan Vanderbyl Apr 29 2011

It’s missing HTTP 418 “I am a teapot”

Sergio Apr 29 2011

Loved mario one

Alexey Romanyuk May 05 2011

It’s a very effective presentation of information. Good work!

Came here from a link from the SEOmoz blog, the author created an a web page status code infographic, and found out that you created something similar. Thanks for the article!

searchengineman Jun 02 2011

I too came from SEOmoz blog article
..nice Info Graphic keep up the good work.


Suren Sarukhanyan Jun 07 2011

hey, nice graphics and nice epxplanation, especially when you come from this article on SEOMOZ :)

Alejandro Jun 22 2011

Thanks for the info! Now I have a question:

What does “Rep” mean, in the context of 4% of 44 Billion pages were “Rep”?

I would appreciate a link to a definition if possible.

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