It's stressful because you have to code while they watch you. The recruiter can ask any question, and you have to communicate, which can make it difficult to think. However, if you are well-prepared, it shouldn't be an issue.
To provide an algorithm.
The following metrics were computed from 5 interview experiences for the Block Software Engineer (Internship) role in Canada.
Block's interview process for their Software Engineer (Internship) roles in Canada is fairly selective, failing a large portion of engineers who go through it.
Candidates reported having good feelings for Block's Software Engineer (Internship) interview process in Canada.