For Walmart (this applies only to this division anyway; it's a huge company with many disparate areas), the process begins after initial contact with a quick test on Hackerrank. I simply applied online and included an aggressive cover letter, which seemed to help cut through the clutter.
Typical HackerRank questions are seemingly easy, but they are about being very good with the latest language features.
The following metrics were computed from 3 interview experiences for the Walmart iOS Developer role in United States.
Walmart's interview process for their iOS Developer roles in the United States is extremely selective, failing the vast majority of engineers.
Candidates reported having very good feelings for Walmart's iOS Developer interview process in United States.