I was just browsing Meta Stack Overflow, when I found this <iframe> hiding below the footer:

Could someone explain why http://teststackoverflow.com/ needs to be embedded at the bottom of the page?

  • are you sure it's not your script that added it? I'm on mobile, but I'm sure I haven't seen this before. Feb 19, 2014 at 10:54
  • It's all explained if you followed that link. @JanDvorak it says they add it to <1% of requests
    – OGHaza
    Feb 19, 2014 at 10:54
  • no this is not my script, I was just browsing election Q&A page and even I got surprise to see a iframe in footer. Feb 19, 2014 at 10:58
  • They're doing some performance testing, which requires a new domain name, or something like that. Related: meta.stackexchange.com/questions/221591/…
    – 3ventic
    Feb 19, 2014 at 11:00

1 Answer 1


Have a look at the website: http://teststackoverflow.com/

it says :

You may have arrived here from looking at our iframe, welcome! We are not adding this extra hit to every request, but less than 1% of the requests to our network.

The intent is to keep ay eye on performance and evaluate infrastructure changes and the impact they have.

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