# Software Engineer
**Role:** Software Engineer · **Level:** L1
**Company:** [Jane Street](https://scaleengineer.com/companies/jane-street)
**Difficulty:** Medium
**Salary:** US$90000 - US$120000
**Experience:** 0 - 2
**Timeline:** ~7 days
The Software Engineer L1 interview at Jane Street is designed to assess foundational programming skills, problem-solving abilities, and a candidate's potential to grow within the company. It typically involves a mix of technical and behavioral assessments to evaluate a candidate's fit for the role and the company culture.
Canonical: https://scaleengineer.com/interviews/jane-street/l1-software-engineer
---
## Overall evaluation

- Technical Skills
- Behavioral and Cultural Fit

## Questions asked

- Write a function to reverse a linked list.
- Given an array of integers, find the two numbers that add up to a specific target.
- Explain the difference between a process and a thread.
- Tell me about a time you had to debug a complex issue.
- How would you design a simple URL shortener?
- What are your favorite programming languages and why?
- Describe a situation where you had to work under pressure.

## Preparation tips

### lists

- Review fundamental data structures and algorithms (arrays, linked lists, trees, graphs, sorting, searching).
- Practice coding problems on platforms like LeetCode, HackerRank, or Coderbyte, focusing on easy to medium difficulty.
- Understand basic object-oriented programming (OOP) concepts.
- Prepare to discuss your resume, projects, and any technical experiences in detail.
- Research Jane Street's business and values to understand the company culture.
- Practice explaining your thought process clearly and concisely.
- Prepare questions to ask the interviewer about the role, team, and company.

### studyPlan

- {"title":"Data Structures and Complexity","longDescription":"Weeks 1-2: Focus on core data structures like arrays, linked lists, stacks, queues, and hash maps. Practice problems involving these structures. Understand time and space complexity analysis (Big O notation).","shortDescription":"Weeks 1-2: Data Structures (Arrays, Linked Lists, Stacks, Queues, Hash Maps) & Complexity Analysis."}
- {"title":"Trees and Graphs","longDescription":"Weeks 3-4: Dive into trees (binary trees, BSTs) and graphs. Learn about traversal algorithms (BFS, DFS) and common graph problems. Practice problems related to these topics.","shortDescription":"Weeks 3-4: Trees (Binary Trees, BSTs) & Graphs (BFS, DFS)."}
- {"title":"Algorithms","longDescription":"Weeks 5-6: Focus on algorithms such as sorting (quicksort, mergesort), searching (binary search), recursion, and dynamic programming. Work through a variety of problems that require applying these algorithms.","shortDescription":"Weeks 5-6: Algorithms (Sorting, Searching, Recursion, Dynamic Programming)."}
- {"title":"Final Review and Behavioral Preparation","longDescription":"Week 7: Review all topics, practice mock interviews, and prepare behavioral questions. Refine your resume and prepare thoughtful questions for the interviewers.","shortDescription":"Week 7: Review, Mock Interviews, Behavioral Prep, Resume Refinement."}

## Location differences

- {"location":"New York","differences":{"tips":["Research the specific technologies used by the team in this location.","Be prepared to discuss your experiences working in diverse teams.","Highlight any contributions to open-source projects or personal coding projects."],"interviewFocus":["Adaptability to different tech stacks.","Collaboration and teamwork skills.","Problem-solving in a collaborative environment."],"commonQuestions":["Describe a challenging bug you fixed.","How do you approach learning a new programming language?","Tell me about a time you disagreed with a teammate."]}}
- {"location":"London","differences":{"tips":["Familiarize yourself with common software development methodologies.","Be ready to articulate your thought process for writing clean and efficient code.","Showcase your enthusiasm for tackling new technical challenges."],"interviewFocus":["Understanding of software development lifecycle.","Attention to detail and code quality.","Passion for technology and continuous learning."],"commonQuestions":["How do you ensure code quality?","What are your thoughts on agile development?","Describe a project you are particularly proud of."]}}

## Round 1: Coding and Problem Solving
**Type:** Technical Interview · **Difficulty:** Easy · **Duration:** 45 min
Assess fundamental coding skills and problem-solving.
This initial technical round focuses on assessing your fundamental programming skills. You will be asked to solve one or two coding problems, typically involving arrays, strings, or basic data structures. The interviewer will evaluate how you approach the problem, your ability to write clean and efficient code, and how well you communicate your thought process.
**Interviewers look for:** Clear thinking; Ability to translate requirements into code; Basic understanding of algorithms and data structures
**Evaluation criteria:** Problem-solving approach; Basic coding ability; Communication of thought process
**Common rejection reasons:** Inability to articulate thought process.; Poor understanding of fundamental data structures.; Difficulty in solving basic coding problems.; Lack of enthusiasm or curiosity.
## Questions

- Given an array of integers, return indices of the two numbers such that they add up to a specific target.
- Implement a function to check if a string is a palindrome.

## Preparation tips

- Practice coding problems on a whiteboard or a simple text editor.
- Focus on explaining your logic step-by-step.
- Be prepared to discuss edge cases and test your solution.

## Round 2: System Design
**Type:** System Design Interview · **Difficulty:** Medium · **Duration:** 60 min
Assess system design capabilities and architectural thinking.
This round evaluates your ability to design and think about larger systems. You might be asked to design a component of a larger application or a system from scratch. The focus is on your approach to design, identifying key components, considering scalability, reliability, and trade-offs. This is less about writing code and more about architectural thinking.
**Interviewers look for:** Ability to break down complex problems; Knowledge of common system design patterns; Consideration for performance, reliability, and maintainability
**Evaluation criteria:** System design thinking; Scalability considerations; Trade-off analysis; Understanding of distributed systems concepts
**Common rejection reasons:** Inability to design a scalable solution.; Lack of understanding of system components.; Poor trade-off analysis.; Not considering failure scenarios.
## Questions

- Design a URL shortening service like TinyURL.
- How would you design a system to count the number of unique visitors to a website?

## Preparation tips

- Study common system design patterns (e.g., load balancing, caching, databases, APIs).
- Practice designing familiar systems (e.g., Twitter feed, URL shortener, chat application).
- Be prepared to discuss the pros and cons of different design choices.

## Round 3: Behavioral and Fit
**Type:** Behavioral Interview · **Difficulty:** Medium · **Duration:** 30 min
Assess behavioral competencies and cultural fit.
This round focuses on your past experiences and how you handle various situations. You'll be asked behavioral questions using the STAR method (Situation, Task, Action, Result). The interviewer wants to understand your work style, how you collaborate, handle challenges, and your overall fit with the company culture.
**Interviewers look for:** Honesty and integrity; Ability to work in a team; Proactiveness and initiative; Alignment with Jane Street's values
**Evaluation criteria:** Behavioral competencies; Teamwork and collaboration; Problem-solving in past experiences; Cultural alignment
**Common rejection reasons:** Poor communication skills.; Lack of self-awareness.; Inability to provide specific examples.; Not aligning with company values.
## Questions

- Tell me about a time you faced a significant challenge at work and how you overcame it.
- Describe a situation where you had to work with a difficult colleague. How did you handle it?
- Why are you interested in Jane Street?

## Preparation tips

- Prepare examples for common behavioral questions (teamwork, conflict resolution, leadership, failure).
- Use the STAR method to structure your answers.
- Be honest and authentic in your responses.
- Show enthusiasm for the role and the company.