Alright vs All right: which is ideal?

Are 'all right' and 'alright' one and the same? Can they be used interchangeably? Or is one correct and the other wrong? 

Let's put the confusion to bed...

'Alright' is a one-word spelling of the phrase 'all right'. 

'Alright' is commonly used in written dialogue and informal writing, but 'all right' is the only acceptable form in edited and formal writing. 

Basically, it is not all right to use alright in place of all right in standard English. And if you can help it, you are better safe going with 'all right' when writing.

Note:

'All right' has a range of meanings:

as an adjective, it means safe; e.g. Are you all right?

or 

'good; reliable': e.g. That fellow is all right.

But as an adverb, 'All right' means 'satisfactorily'; e.g. The man's efforts are coming along all right.

or 

'yes'; e.g. All right, I’ll go with you.