I had 2 rounds. The process was.
Recruiter screen: Behavioral and preliminary tech round where they ask about your experience and a hypothetical API design question about an e-commerce company making calls to the Meta API. I studied CAPI and Meta pixel.
The following metrics were computed from 5 interview experiences for the Meta Solutions Architect role.
Meta's interview process for their Solutions Architect roles is incredibly easy as the vast majority of engineers get an offer after going through it.
Candidates reported having very good feelings for Meta's Solutions Architect interview process.