Great question! The term “full stack” is typically written as two words when used as a noun (e.g., “I work with the full stack”), but it can be hyphenated as “full-stack” when used as an adjective (e.g., “She is a full-stack developer”).

Examples:
✅ He specializes in the full stack of web technologies. (noun)

✅ She is a full-stack developer. (adjective)

So, in your original question — “Who is a full stack developer?” — it’s more grammatically correct to write it as:
https://www.sevenmentor.com/full-stack-training-institute-in-pune.php

“Who is a full-stack developer?”

Let me know if you want tips on how to become one
https://www.sevenmentor.com/full-stack-training-institute-in-pune.php