A recruiter approached me via email.
I had a quick online interview with typical HR questions (experience, why you'd like to join, etc.) and four very simple technical questions. The interviewer was very polite and explained the entire process.
Afterwards, I received a coding challenge via email and was given three weeks to complete it. The interviewer guaranteed I could take my time.
I completed it in approximately 10 hours over the span of a week and a half (due to a busy week at work). I delivered the results pretty confidently, having written clean code with tooling, comments, and even specs.
After that, in half a day, I received a single "no" with zero feedback. I suspect they are not measuring your ability to solve the problem, but something else, as it was pretty much solved perfectly.
Anyways, I was saddened by the lack of feedback. As others pointed out, if we gave them hours of our time, they could at least point out what was missing.
The coding challenge was confidential.
The first technical questions were very basic JavaScript, though.
The following metrics were computed from 1 interview experience for the Meta Front End Engineer role in Brazil.
Meta's interview process for their Front End Engineer roles in Brazil is extremely selective, failing the vast majority of engineers.
Candidates reported having very negative feelings for Meta's Front End Engineer interview process in Brazil.