Scale Engineer

Senior Software Engineer

Software EngineerL4Medium to Hard

The Senior Software Engineer (L4) interview process at Criteo is designed to assess a candidate's technical expertise, problem-solving abilities, system design skills, and cultural fit. It typically involves multiple rounds, including technical interviews, a system design interview, and a behavioral/managerial interview. The process aims to identify individuals who can contribute significantly to complex projects, mentor junior engineers, and uphold Criteo's engineering standards.

Rounds·3

Timeline·~14d

Experience·4 - 10 yrs

Comp band·US$110000 - US$150000

Interview time·150 min

Evaluation

What they measure.

  • Problem-solving skills
  • Algorithmic thinking
  • Coding proficiency and best practices
  • Data structures knowledge
  • System design capabilities
  • Scalability and performance considerations
  • Communication skills
  • Teamwork and collaboration
  • Cultural fit and alignment with Criteo values

Preparation

How to prepare.

Tips

  1. Review fundamental computer science concepts (data structures, algorithms, operating systems, databases).
  2. Practice coding problems regularly, focusing on efficiency and clarity.
  3. Study system design principles and common architectural patterns.
  4. Prepare specific examples from your past experience to answer behavioral questions using the STAR method (Situation, Task, Action, Result).
  5. Research Criteo's products, services, and company culture.
  6. Understand the technologies commonly used at Criteo (e.g., Java, Python, Scala, distributed systems, cloud platforms).
  7. Prepare thoughtful questions to ask the interviewer about the role, team, and company.

Study plan

Fig · Study plan — 04 phases

01 / 04
01

Phase 01 of 04

Data Structures and Algorithms Fundamentals

Weeks 1-2: Data Structures & Algorithms (Medium LeetCode).

Weeks 1-2: Focus on core data structures (Arrays, Linked Lists, Trees, Graphs, Hash Tables) and algorithms (Sorting, Searching, Dynamic Programming, Graph Traversal). Practice implementing these efficiently and analyze their time/space complexity. Solve LeetCode problems tagged 'Medium'.

Questions

Commonly asked.

  • Describe a time you had to deal with a difficult stakeholder. How did you handle it?
  • How would you design a system to handle real-time bidding in advertising?
  • What are the trade-offs between monolithic and microservices architectures?
  • Write a function to find the k-th largest element in an unsorted array.
  • Explain the concept of eventual consistency.
  • Tell me about a project you are particularly proud of and your role in it.
  • How do you approach debugging a complex distributed system?
  • Design an API for a simple e-commerce product catalog.
  • What strategies do you use to ensure code quality and maintainability?
  • How do you stay updated with new technologies and industry trends?

Locations

Regional differences.

Fig · Regions — 02 locations

01 / 02

Location

Paris

Interview focus

Strong emphasis on practical problem-solving and coding proficiency.System design questions often relate to Criteo's ad-tech domain.Behavioral questions focus on collaboration and impact within a team.

Common questions

  • How would you design a URL shortener service?
  • Discuss a challenging technical problem you solved recently.
  • Explain the trade-offs between SQL and NoSQL databases.
  • How do you handle concurrency in your applications?
  • Describe your experience with cloud platforms (AWS, GCP, Azure).

Tips

  • Familiarize yourself with Criteo's core business and technologies.
  • Practice coding problems on platforms like LeetCode, focusing on medium to hard difficulty.
  • Prepare detailed examples for behavioral questions using the STAR method.
  • Research common system design patterns and be ready to discuss trade-offs.

Rounds

Round-by-round.

Expand a step for evaluation criteria, sample questions, and prep notes.

Med

Technical Phone Screen / Online Assessment · 45 min · Software Engineer

This initial technical round focuses on assessing your core programming skills and problem-solving abilities. You will be asked to solve one or two coding problems, typically involving data structures and algorithms. The interviewer will evaluate how you approach the problem, your thought process, the efficiency of your solution, and the clarity of your code. Expect to write code in a shared editor or on a whiteboard.

What they look for

Logical thinkingAbility to translate requirements into codeUnderstanding of fundamental CS conceptsClean and efficient coding style

Evaluation

  • Problem-solving approach
  • Correctness of the solution
  • Code efficiency (time and space complexity)
  • Code readability and maintainability
  • Communication of thought process

Sample questions

  • Given a binary tree, invert the tree.

    Data StructuresRecursionTree

  • Find the first non-repeating character in a string.

    StringsHash TableArrays

  • Implement a function to check if a linked list has a cycle.

    Linked ListPointersAlgorithms

Prep for this round

  1. 01Practice coding problems on platforms like LeetCode, HackerRank, or Coderbyte.
  2. 02Focus on understanding the time and space complexity of your solutions.
  3. 03Be prepared to explain your approach before you start coding.
  4. 04Practice thinking out loud as you solve problems.

Common rejection reasons

  • ×Inability to articulate thought process clearly.
  • ×Poor coding practices (e.g., inefficient code, lack of error handling).
  • ×Fundamental misunderstanding of data structures or algorithms.
  • ×Difficulty in solving even basic coding problems.

DSA

Coding questions at Criteo.

Frequently reported on Criteo loops

View all at Criteo

Other guides

More at Criteo.