I applied through a recruiter. The process took 3 weeks.
CodeSignal -> Superday.
CodeSignal was standard GCA and Superday has case study, LeetCode, and behavioral. All pretty easy and standard. Four hours long with an hour break before the behavioral and after the technical.
The following metrics were computed from 400 interview experiences for the Capital One Software Engineer role.
Capital One's interview process for their Software Engineer roles is fairly selective, failing a large portion of engineers who go through it.
Candidates reported having very good feelings for Capital One's Software Engineer interview process.