Karat Software Engineer Interview Experience — Password Validator and a Three-Table Join Over Bad Audio

Karat·Software Engineer·Jan 2026
Technical Screenmedium

Weird screen, hard to categorize, but I hope this gets seen anyway...

Classic low-quality Amazon-customer-service-tier microphone. I've worked with people like this for years and I still only understood about 50% of what the interviewer said. Fortunately they noticed too, so I politely asked them to speak a bit slower, and it got a lot better after that.

Right at the start they said I didn't need to finish every question. There was only one code pad, I wrote it in Java, and ran everything straight off main.

First question: the input is a password, and you need to determine whether it's valid and list which rules it violates.

  • Length greater than 15
  • Cannot contain "password" (case-insensitive)
  • Must have at least one uppercase and one lowercase letter
  • Must contain at least one of three special symbols
  • The same character cannot appear more than four times

Second question: three tables, each given as a 2D string array. You need to match and join them.

  • Customer table: name, email, product name, quantity purchased (each user only buys one type of product)
  • Order table: user id, email, order total amount (email can be null)
  • Product table: product name, unit price

You need to find the mapping from user id to name.

The interviewer was useless beyond just handing me the questions.

Published

Curated and edited by PracHub

Practice the questions from this interview

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Interview at a glance

Company
Karat
Role
Software Engineer
Rounds
Technical Screen
Difficulty
medium
Interview date
Jan 2026
Questions from this interview
2 questions

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