“All right” vs. “Alright”: Which One To Use

Both forms are correct by US writing standards. The main consideration when it comes to using “all right” versus “alright” is the purpose of your writing and how it might be received by your reader. 

Some posit that “alright” is an appropriate spelling for informal usage, like in a text message or brief email to a coworker or in fiction writing to characterize colloquial dialogue. Conversely, the use of “all right” is better suited for formal correspondences, such as in a professional report, official business letter, or academic paper.