You must have come across both variants, probably wondering which one is more preferable. Well, the quick answer to this question is all right.
The tea was all right.
Unlike much older mergers such as altogether and already that are fully acceptable, using alright, especially in formal writing, is still highly likely to make your readers think that your English is far from perfect.
So play it safe and use all right.
In case you want to use it but can’t recall which variant is correct, avoid it altogether.
I thought the film was all right.
Here, all right means okay or satisfactory. You can reword, e.g. I thought the film was okay.
The leading actress played all right.
Here, all right means fairly well. Reword, e.g. The leading actress played rather well.
All right, guys, I’d like to introduce our first speaker this evening.
Here, all right is an interjection that means very well. You can either delete it or reword, e.g. Right then guys, I’d like to introduce our first speaker this evening.
It’s not rocket science, is it?