Stripe Software Engineer Interview Guide

This is an initial call with the recruiter, which would typically be an informal chat. You will discuss your experiences, your background, etc. You can ask the recruiter various questions such as the different roles at the company, and what is expected of you if you join the company.

The recruiter will also schedule the next round i.e., the technical screening round.

• What do you know about Stripe?
• What about Stripe makes you want to work here?
• What are your career aspirations?
• Talk about a project you’re most proud of.

This will be a video call with an engineer or hiring manager from the team. It will typically be a 1-hour interview. The first 5-10 minutes are a quick intro, after which you will be required to share your screen and do live coding in the language of your choice. 

The interviewer will typically ask only one question but will have many follow-up questions. Test cases will be provided and you will have to code the solution such that the tests pass. 

Depending on the time left, you may also have a chance to ask questions to your interviewer

Note - The interview is designed to be of a pair-programming type, where your "pair" will be the interviewer. The coding questions will test the following topics - 

• System Design
• Databases
• Heaps
• Data Structures

If you don't do well enough to pass the Stripe rubrik - you might be asked to do a follow-up 2nd round which follows a similar format

• Problem statements can look complicated and unusual since Stripe nearly never asks traditional Leetcode questions. In this context it's very important to clarify the goal and make sure you're understanding what the interviewer wants you to achieve before you start coding.
• Focus on writing good code i.e. readable (eg. proper indentation, formatting etc), and easy to understand (few comments to explain the procedure, logical arrangement, sensible variables etc). 
• The interviewer wants to understand your thought process, so it’s okay to check in with them periodically to make sure you're on the right track. If you get stuck, it's better to just say that transparently in an effort to make progress rather than continue to use blunt force if you aren't getting anywhere.
• Practice interviews in pair programming format so that you’re able to understand the flow of the round.

• Print all nodes less than a given value x from the min-heap.
• Given a sample database, write the unit tests to cover all cases.
• Create a database class for a given problem. 
• Design a method to find the minimum value in a given column of the given database.
• Design a function from a given database. 
• Design a data structure that can store a unique data type. 

Note - Simple questions based on if/else conditions, parsing, and arrays can also be asked.

This is the final round of interviews. It generally consists of 5 interviews (in no particular order) which take place over a period of 3-4 hours -

• Coding interview
• Behavioral round with Hiring Manager
• Bugbash / bugfixing round
• System Design 
• Problem Solving / Integration Interview

Before the onsite, you will receive a preparation guide to know what to expect and what to practice for. Explore similar processes detailed in the Visa Software Engineer guide.

1. Coding interview  

This interview will test your coding skills. It's important to know Stripe doesn't ask traditional leetcode questions; they will ask questions which emulate the sort of work you'd actually be doing day to day. So you might get questions which are a bit of a deviation from the standard coding DSA interviews you might have traditionally prepared for.

Sample Questions - 

• How would you ensure personally identifiable information isn't accessible to people who don't need access to it within Stripe
• Design a rate limiter from scratch.

2. Behavioural Round with Hiring Manager

This will consist of leadership-oriented and behavioral-type questions. Stripe has a high bar in terms of fit, so anticipate questions which are both experiential (eg. tell me about a time) and situational (eg. how would you handle a scenario) in nature. Strongly recommend leveraging the STAR method to answer the questions - Situation, Task, Action, Result, and maybe adding an extra R for Reflection or Retrospective, to make sure you can demonstrate you learnt from these experiences

Sample questions - 

• What is something you would have done differently in a project?
• Discuss a time when you disagreed with a team decision. What did you do about it? 
• Talk about a time when you had to resolve a difficult situation within the team.
• Tell me about a time you made a mistake. What did you learn from it? 

3. Bug Bash / Bugfixing round

In this round, you will be given a codebase, and you’ll have to run various tests to identify the bug(s) in the program and provide the most accurate fix. You will be provided with resources such as a failing test to help identify the bugs. You will have to complete the entire process in a given amount of time. 

Note - Generally, the bugs are easy to recognize and fix. What makes the task difficult is the code. It may be difficult to understand the code due to a lack of comments and advanced coding components that are rarely used. 

Stripe often uses bugs they've actually encountered before -- so you will quite likely get some version of an actual bug they've found in their code at some point.

It's really important to break the problem space down into themes and approach step by step rather than going after the first "good idea". A structured, methodical approach is graded highly here.

4. System Design

In this round, you will be required to design a system. This round aims to assess how you build a large-scale system, your thought process, and what information you take into account while designing it.

Tips:

• Clarify all doubts with the interviewer before you start designing the system. You will nearly definitely have to make some assumptions, it's important to flag these explicitly rather than make them implicitly.
• The interviewer wants to know your approach towards the problem, so think aloud as you navigate it and break down the steps.
• Interviewers particularly value thought processes around tradeoffs, prioritizations and edge cases, so make sure you demonstrate competence around these
• It's crucial to think of how things would scale to very high volumes / concurrency, so factor in these requirements upfront in your architecture.

Sample questions - 

• Design a database for a product such as a toy.
• Design the frontend and backend for a logging system.
• Design an architecture for delivering webhooks to customers.
• Design a notification system that can deal with a huge amount of traffic. 
• Sketch out the high-level design of a large system for a large company. 

5. Integration Task

In this round, you will be required to integrate new code into an existing codebase. You must be familiar with HTTP Rest calls, parsing JSON, and sending requests to APIs. For more senior roles -- you will basically be using the Stripe API directly to simulate something that a client or merchant might do with this API.