Every time. Here is what a grammar blog says: Everytime should be written as two separate words: every time. While some compound words like everywhere, everyday, and everyone have become commonplace in the English language, everytime is not considered an acceptable compound word.

"Every time" is written as two separate words. However, you can write "everywhere", "everyone", and "everyday" as one word.

It should be written every time but writing non-academically it won't matter and nobody will care if you use it as one word.