Hi,
I’m getting 400 “Invalid key” with a key that used to work fine.
I did go over the 200 daily limit at some point, but thought this would be reset after 24 hours.
Do API keys expire at some point?
We created a few keys from the same email domain… Looks like they are now considered “disposable emails” and that all the keys got disabled 
There is some text about registering multiple keys to bypass the testing limits on the registration page (and yes, when that happens I nuke the keys). If you re-register a single key it should work.
I saw that after the fact… Sorry about this.
We did find a solution.
Thanks for your time and this service.
Where I work we have 6 dotcom domains. Is it acceptable to register a key per domain or are we supposed to use a single key across all domains?
For the public WebPageTest instance you are limited to 1 key across all of the domains.
If you need to do some form of regular monitoring you should use an actual monitoring service like SpeedCurve, Catchpoint, etc.
If you need to use the API but run higher volumes of tests you will need to run your own private WebPageTest instance (there are AMI’s available for AWS that make it relatively easy).