Revolut interview - coding session [Rejected]
Interview Experience
That was a Python interview for a senior role. The interviewer was nice and answered the questions about the tasks. Rejection letter: `Unfortunately, after much consideration, we have decided not to p
Full Details
That was a Python interview for a senior role. The interviewer was nice and answered the questions about the tasks. Rejection letter: Unfortunately, after much consideration, we have decided not to proceed further with your application, as we require more specific knowledge to be successful in our recruitment process. Tasks were very easy for me. I spent more time asking the interviewer what he wanted to see in my code. Coding session took around an hour. Write a class that will register strings, but no more than 10 of them (raise an error in case of overflow). Make a test for that. Add a method `get` that will randomly return one of the strings. Write a test for that method. Make it possible to switch `get` to round robin. Write a test for that.
My solution was written during an interview. app.py removed redundant spaces from random import choice from typing import Callable from revolut.constants import BALANCER_INSTANCE_LIMIT class BalancerError(Exception): ... class AlreadyRegisteredInstance(BalancerError): ... class OverLimitInstances(BalancerError): ... class EmptyInstancesRegistry(BalancerError): ... class RoundRobinStrategy: def init(self): self._current_index = 0 def call(self, instances: list[str]) -> str: element = instances[self._current_index] self._current_index = ( self._current_index + 1 if self._current_index < len(instances) - 1 else 0 )
return element class Balancer: def init(self, randomizer: Callable = choice): self._randomizer = randomizer self._instances = list() def register(self, url: str) -> None: if url in self._instances: raise AlreadyRegisteredInstance("Instance already registered") if len(self._instances) == BALANCER_INSTANCE_LIMIT: raise OverLimitInstances(f"{BALANCER_INSTANCE_LIMIT}") self._instances.append(url) def get(self) -> str: if len(self._instances) == 0: raise EmptyInstancesRegistry return self._randomizer(self._instances)
About This Question
This is a candidate experience report from a revolut interview for a swe role (senior level) during the technical round reported in 2025.
It covers the following topics: Strings, System Design .
Difficulty rating: Easy
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This question was reported by a candidate who interviewed at Revolut. LeakCode aggregates interview reports from 10+ sources, including 1Point3Acres, Glassdoor, LeetCode Discuss, Blind, Reddit, Indeed, and Nowcoder. Each report is translated where necessary, deduplicated against existing entries, and tagged by company, role, round type, and reporting date.
Use this question as one calibration data point, not a memorization target. Companies typically rotate their question pools every 2-4 months; the exact wording of a 2024 question may differ from what you encounter today. The underlying pattern, difficulty level, and follow-up depth at Revolut are the higher-signal extractions to take from this report.
For broader preparation context, the Revolut interview process typically includes a recruiter screen, one or two technical phone screens, and a 4-5 round on-site loop covering coding, system design (at L4+ levels), and behavioral. Reports tagged on LeakCode show the round-by-round distribution and typical difficulty calibration. To browse questions filtered by round type and seniority, use the company hub linked above.
How To Practice This Type of Question
Solve similar problems on LeetCode under timed conditions (25-35 minutes per medium difficulty). The goal is pattern recognition: recognize the underlying technique (sliding window, two-pointer, BFS, memoized recursion, etc.) within 60-90 seconds of reading. Strong candidates verbalize their hypothesis out loud before coding, then iterate based on feedback. Weak candidates dive into implementation immediately, lose time on the wrong approach, and run out of time for follow-ups.
Companies update their question pools every 2-4 months. The exact wording of any given question may have been retired by the time you interview. Focus your prep on the pattern, not the specific problem. The patterns that appear in Revolut reports consistently are the ones worth investing in; one-off niche problems are not.
During Your Revolut Round
Apply the standard interview round template: clarify requirements (2-3 minutes), state your approach out loud and confirm direction with the interviewer (3-5 minutes), code with narration (15-25 minutes), test with concrete examples including edge cases (5 minutes), discuss optimization or trade-offs if time permits (5 minutes). This template is universally accepted across FAANG and adjacent companies; deviating from it produces weaker interviewer feedback signal.
The single most predictive failure mode in Revolut reports tagged "no hire": not asking clarifying questions. Interviewers are explicitly trained to weight this. Strong candidates ask 3-5 clarifying questions even on problems that look obvious; weak candidates dive into code immediately. The clarifying-question check is often the first signal recorded in the interviewer's written notes.