Criteo Site Reliability Engineer interview questions & guide 2026

The questions below represent common patterns reported by candidates during their assessment for the Site Reliability Engineer role. While specific questions may evolve, these categories capture the core competencies Criteo prioritizes.

Technical & Systems Knowledge

This category tests your foundational understanding of the infrastructure, networking, and operating systems that support large-scale web platforms.

• Can you explain the OSI model and how it relates to troubleshooting a network issue?
• How does DNS resolution work in a high-traffic environment?

Preparation at Criteo should be strategic and focused. You are being evaluated not just on what you know, but on how you apply that knowledge to real-world, large-scale problems.

Role-related knowledge – You must demonstrate a mastery of Linux internals, networking protocols, and modern infrastructure automation. Interviewers want to see that you understand the "why" behind system behaviors, not just the "how."

Problem-solving ability – When faced with an ambiguous system design or a coding challenge, structure your response clearly. Start by defining your assumptions, explain your thought process as you iterate, and always consider edge cases or potential failure modes.

Leadership & Communication – Even in a technical role, your ability to explain complex concepts to non-experts and collaborate with cross-functional teams is critical. Be ready to articulate how you influence technical decisions and how you handle conflict within a team.

Culture fit – Criteo values engineers who are curious, collaborative, and resilient. Demonstrate your interest in the company’s business model and your willingness to take ownership of production issues.

The interview process at Criteo is designed to be rigorous, reflecting the high-scale nature of their engineering challenges. You can expect a multi-stage process that begins with a recruiter screen, followed by a series of technical assessments that probe your depth in coding, system design, and operations. While the process is comprehensive, its primary goal is to ensure that candidates possess both the technical depth and the collaborative mindset required to succeed in a fast-paced environment.

Typically, the process moves from initial screening to deeper technical rounds, which may include live coding, system design, and behavioral interviews. You will likely interact with both peers and managers, providing you with a well-rounded view of the team and the company culture. Be prepared for a process that values precision and depth; interviewers will look for evidence of your experience and your ability to navigate complex, open-ended scenarios.

This timeline illustrates the progression from initial screening to final onsite or remote assessment rounds. Candidates should use this structure to pace their preparation, ensuring they are ready to pivot from broad technical discussions to deep-dive coding and design sessions. Note that while the flow is generally consistent, the number of rounds can vary depending on the specific team and seniority level of the role.

System Design & Architecture

This area evaluates your ability to design scalable, fault-tolerant infrastructure. You should be prepared to discuss how to build systems that can handle massive traffic spikes.

Be ready to go over:

• Load balancing strategies and their impact on latency.
• Database sharding, replication, and consistency trade-offs.
• Caching strategies to improve system performance.
• Advanced concepts: Microservices orchestration, service mesh, and global traffic management.

Example scenarios:

• "Design a URL shortening service that can handle millions of requests."
• "How would you architect a system to handle a sudden 10x surge in traffic?"
• "Explain how you would ensure data consistency in a distributed database."

As a Site Reliability Engineer, you are the guardian of Criteo's production environment. Your primary responsibility is to ensure that the services powering the company’s advertising platform remain performant and available. This involves constant monitoring, proactive capacity planning, and the rapid resolution of production incidents.

You will spend a significant portion of your time automating operational tasks. By writing scripts and building tools, you will reduce "toil" and improve the efficiency of the entire engineering organization. You will also participate in on-call rotations, where you will be responsible for diagnosing and fixing issues in real-time, often working alongside software engineers to identify root causes and implement permanent fixes.

Collaboration is a core pillar of your day-to-day work. You will act as a consultant for product and development teams, providing guidance on how to build software that is inherently reliable. By embedding yourself in the development lifecycle, you ensure that performance and stability are considered from the very first line of code.

A strong candidate for this role possesses a blend of deep technical expertise and a pragmatic, solution-oriented mindset. You are expected to have a solid foundation in both software engineering and systems administration.

• Must-have skills:

  • Proficiency in at least one scripting or programming language (e.g., Python, Go, or Bash).
  • Deep understanding of Linux/Unix internals and networking (TCP/IP, DNS, HTTP).
  • Experience with configuration management tools and infrastructure-as-code.
  • Demonstrated experience managing large-scale, distributed production systems.

• Nice-to-have skills:

  • Experience with container orchestration platforms like Kubernetes.
  • Familiarity with cloud infrastructure providers and their specific service offerings.
  • Exposure to observability stacks (e.g., Prometheus, Grafana, ELK).

Q: How long should I spend preparing for these interviews? A: Given the technical rigor of the process, most successful candidates spend several weeks reviewing core computer science concepts, practicing coding problems, and brushing up on distributed systems theory. Focus on both breadth and depth to ensure you can handle both high-level architecture and low-level troubleshooting.

Q: What differentiates successful candidates from others? A: Successful candidates don't just provide "correct" answers; they demonstrate a deep curiosity and a methodical approach to problem-solving. They are able to communicate their thought process clearly, acknowledge trade-offs in their designs, and show a genuine passion for reliability engineering.

Q: What is the culture like at Criteo? A: Criteo is known for a collaborative and open culture where technical excellence is highly valued. You will find that team members are generally approachable and willing to share knowledge, though the work environment is fast-paced and demands a high level of individual ownership.

Q: How are the technical interviews structured? A: You can expect a mix of live coding assessments, system design discussions, and operational deep-dives. Some interviews may be more theoretical, while others will focus on practical, day-to-day scenarios you might encounter in the role.

• Think out loud: During coding and design sessions, explain your reasoning as you go. This helps the interviewer understand your thought process, which is often more important than arriving at the "perfect" solution.
• Clarify the requirements: Before diving into a solution, ask clarifying questions to ensure you fully understand the constraints and goals. This demonstrates maturity and a focus on requirements.
• Prepare for the "Why": Don't just explain how a system works; explain why you chose a specific tool or architectural pattern over alternatives. Understanding trade-offs is a hallmark of a senior engineer.
• Review your resume: Be prepared to discuss any project on your resume in extreme detail. If you list a technology, expect to be asked about its internals and common failure modes.

The Site Reliability Engineer role at Criteo offers a unique opportunity to tackle some of the most challenging infrastructure problems in the industry. By combining your technical expertise with a proactive, collaborative mindset, you can play a pivotal role in maintaining the reliability and performance of a platform that operates at a massive, global scale.

Preparation is the key to success. Focus on mastering the fundamentals of distributed systems, sharpening your coding skills, and practicing how to articulate your technical decisions under pressure. You can explore additional interview insights, practice questions, and preparation resources on Dataford.

The provided compensation data gives you a high-level view of the salary ranges and components typical for this level of role in the market. Use this information to benchmark your expectations, keeping in mind that total compensation packages often include bonuses, equity, and benefits that reflect the seniority and location of the position.