The online assessment is through HackerRank. Depending on the position, you can choose the language.
For a Front End Developer, you must use JavaScript.
The questions were easy-medium level difficulty.
After this is the on-site interview, with behavioral questions, etc.
Selection of HackerRank questions (easy-medium)
The following metrics were computed from 2 interview experiences for the IBM Back-End Developer role in United States.
IBM's interview process for their Back-End Developer roles in the United States is fairly selective, failing a large portion of engineers who go through it.
Candidates reported having very good feelings for IBM's Back-End Developer interview process in United States.