Software Engineer · Online Assessment · Coding

Meta — Software Engineer ❌ Failed

Level: Senior-Level

Round: Online Assessment · Type: Coding · Difficulty: 7/10 · Duration: 90 min · Interviewer: Unfriendly

Topics: Object-Oriented Design

Location: San Francisco Bay Area

Interview date: 2026-02-15

Got offer: False

Summary

I participated in an online assessment that involved designing a bank system with increasing levels of functionality. I completed three out of four levels.

Details

The online assessment consisted of an object-oriented design problem. I had to design a bank system with time-aware transactions. The timestamp for each transaction was guaranteed to strictly increase. There were four levels, each building upon the previous one:

• Level 1: Implement deposit and withdraw functionalities for users.
• Level 2: Implement a function to get the top active users by "transaction" value. The transaction value is the sum of all successful operations. For example, if a user deposits $100 at time_1 and withdraws $50 at time_2, the transaction value at time_3 is $150 (different from the balance). The function should output the top K users with the highest transaction values.
• Level 3: Implement transfer functionality with two functions: one for the source user to initiate a transfer and another for the target user to accept the transfer. Transfers have an expiration time. Only accepted transfers are added to the transaction value. When a transfer is created, the amount is deducted from the source user's account. If the transfer is not successful, a refund should be issued.
• Level 4: I did not have time to reach this level.

I did not pass one test case in Level 3, and I submitted the solution because there was no time left. I discovered edge cases in Level 3 during debugging failed unit tests that were not mentioned in the problem description.