OtterAI·Software Engineer·Technical Phone Screen
Jun 2026
Technical phone screen for a Software Engineer role at OtterAI. The whole thing was basically one meaty coding problem around password validation, which sounds boring on paper but had enough moving parts to keep me on my toes. They wanted implementation, complexity analysis, and self-written unit tests all in one go.
- Implement a password validation function that accepts a password string and a configurable rule set, returning whether the password is valid and which specific rules failed. Rules include minimum length, forbidden characters, a per-character repeat limit, uppercase/lowercase requirements, and a configurable special character set.
- For each rule in your implementation, explain the time and space complexity.
- Write your own unit tests covering minimum length boundary conditions, each forbidden character, the 4th versus 5th occurrence of a repeated character, missing each character class, and a fully valid password.
“I started with the linear scan plus a frequency map approach, which they seemed fine with.” The rest of the author's notes on Software Engineer interview at OtterAI, Technical Phone Screen round, covers how they worked through the question, what the panel pushed back on, and what they would do differently.
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