Does noindex in robots.txt work with Google?

Post updated: 02/07/2019
No, not as of September 2019, according to a Twitter update from Gary Illyes who announced Google will be dropping undocumented support for noindex in robots.txt

It was fun while it lasted…

TL;DR SEO test

Another terrible SEO test. This time, I have used the robots.txt file on this site to block the indexing of this page.

Has it worked?

Does Google support noindex in robots.txt?

This is what Google’s John Mueller said:

There is obviously a difference between ‘officially support’ and support. Gary Illyes apparenty is going to be “cleaning up that part of the googlebot codebase”, to remove the unofficial support.

So it might be helpful to have this page here as a canary in the mine. The current result of this test is:

Google does support noindex via robots.txt

Indexing blocked by robots.txt noindex