Job ID: r19661
What You'll Do:
Within the Platform department of R&D, the Product Reliability Engineering (PRE) group acts as the bridge between Product Engineering, Platform Engineering and Infrastructure. The Platform PRE group comprises eight teams helping R&D design, build, and operate large-scale distributed systems reliably and efficiently. The common objective of the PRE teams is to build the most reliable platform in AdTech.
As a Senior Software Engineer focused on performance and reliability, you will work closely with product engineering teams to analyze, troubleshoot, and optimize large-scale .NET applications running in production.
Your work will span performance profiling, runtime optimization, reliability engineering, observability, and incident prevention. You will help teams identify bottlenecks, improve application efficiency, and build tooling and frameworks that enhance reliability across the platform.
This role is ideal for engineers who enjoy both low-level technical investigation and hands-on software development, while working on infrastructure supporting billions of real-time requests with latency requirements below 10ms.
Your Responsibilities
Performance & Runtime Engineering
Analyze memory allocations, garbage collection behavior, and runtime performance using tools such as dotnet-trace, PerfView, TraceEvent, WinDbg, dotnet-dump, and CLRmd.
Investigate production bottlenecks through load testing, CPU sampling, profiling, and system analysis.
Debug and troubleshoot complex real-world .NET applications running at scale.
Reliability & Platform Engineering
Review application architecture and code with a focus on performance, scalability, and reliability.
Build troubleshooting, monitoring, and regression testing frameworks for .NET services.
Help improve application performance and operational reliability across the organization.
Participate in technical migrations to modern runtimes and libraries (e.g. .NET 10).
Collaboration & Technical Leadership
Work closely with product engineering teams to promote best practices around profiling, troubleshooting, and production readiness.
Lead workshops and knowledge-sharing sessions on performance engineering and observability.
Contribute to open-source projects used internally, including dotnet/runtime and microsoft/perfview.
Tech Stack : C#, .NET Core, Linux, Windows, Mesos, PerfView, WinDbg, CLRmd, dotnet-trace, and related performance engineering tooling.
Who You Are:
Strong software engineering experience in C# and .NET, including designing, building, testing, and operating production systems.
Solid understanding of Microsoft .NET runtimes, memory management, garbage collection, and application performance.
Interest in low-level performance analysis, profiling, debugging, and runtime behavior investigation.
Experience troubleshooting distributed systems and production environments at scale.
Strong engineering fundamentals with a focus on reliability, automation, observability, and maintainability.
Ability to collaborate effectively across teams, mentor other engineers, and drive technical initiatives.
Curiosity, ownership, and a pragmatic approach to solving complex technical problems.
Take a look at our R&D blog on Medium for access and insight into our engineering culture and achievements.
We acknowledge that many candidates may not meet every single role requirement listed above. If your experience looks a little different from our requirements but you believe that you can still bring value to the role, we’d love to see your application!
Who We Are:
We’re Criteo, the Commerce Intelligence Platform. Criteo helps businesses turn shopper signals into commerce outcomes while delivering more relevant experiences for shoppers. We use proprietary commerce intelligence and AI decisioning to drive relevance for shoppers and performance for businesses.
At Criteo, our culture is as unique as it is diverse. From our offices across the globe or from the comfort of home, our 3,600 Criteos collaborate together to build an open, impactful, and forward-thinking environment.
We foster a workplace where everyone is valued, and employment decisions are based solely on skills, qualifications, and business needs—never on non-job-related factors or legally protected characteristics.
What We Offer:
🏢 Ways of working – Our hybrid model blends home with in-office experiences, making space for both.
📈 Grow with us – Learning, mentorship & career development programs.
💪 Your wellbeing matters – Health benefits, wellness perks & mental health support.
🤝 A team that cares – Diverse, inclusive, and globally connected.
💸 Fair pay & perks – Attractive salary, with performance-based rewards and family-friendly policies, plus the potential for equity depending on role and level.
Additional benefits may vary depending on the country where you work and the nature of your employment with Criteo.
