Is it mandatory to take IELTS for admission or visa purposes, or can I use Duolingo as an alternative?

It depends. Many Irish universities accept the Duolingo English Test for admission if you meet their minimum score requirements, but this varies by institution and program.

For the student visa, Irish immigration authorities typically require proof of English proficiency through tests like IELTS, TOEFL, or PTE Academic. Duolingo is less commonly accepted for visa purposes, so IELTS is usually the safer and more widely accepted option.