Let's say I just passed a certification exam in a certain technology ABC.
Which of the following is/are correct? If more than one is, how do they differ?
- I'm certified on ABC
- I'm ABC certified
- I have a certification on ABC
I was about to just upvote @nihilist_frost but I have a few quibbles with his answer.
First: You can be "certified in" a subject. Like "I am certified in diesel engine repair." You can be "certified on" a particular machine or tool. "I am certified on turret lathes." You can be "certified as" a profession. "I am certified as a hairdresser."
Second: If you say, "I am ABC certified", "ABC" could be the organization that gave you the certification, or it could be the subject matter. Like, "I am Microsoft-certified", or "I am Java certified."
I'm certified on ABC
There should be a "in" instead of "on".
This means that you have proven your merits on ABC, via a certificate or something. A correct sentence.
I'm ABC certified
There should be a hyphen between ABC and "certified".
ABC is the name of the organization that certified you.
This means that you have been certified by ABC for something. This doesn't fit with your context, because in your case ABC is not the name of the organization that tested you.
I have a certification on ABC
Again, there should be an "in" instead of "on".
This means that you have an event where you get certified for something coming up at some point. It doesn't fit because the certification exam has already finished.