Library Software Engineer - C++

The APM Team at Datadog provides mission critical application health and performance monitoring for customers of all sizes and industries. We’re taking a new approach to APM with distributed tracing, profiling and seamless integration with Datadog’s Infrastructure and Logs products. Datadog is building a world-class APM product that traces requests as they flow across complex systems. We’re looking for a seasoned C++ engineer to shape the libraries and runtime hooks that power observability inside web infrastructure like Nginx, Kong, and Envoy. 

At Datadog, we place value in our office culture - the relationships that it builds, the creativity it brings to the table, and the collaboration of being together. We operate as a hybrid workplace to ensure our employees can create a work-life harmony that best fits them.

What You’ll Do: 

• Develop and maintain high-performance C++ libraries that integrate with reverse proxies to enable observability and diagnostics.
• Design and implement runtime instrumentation for latency-sensitive and multi-threaded systems.
• Contribute to our adoption and integration of OpenTelemetry standards across Datadog’s C++ observability libraries.
• Own the performance, safety, and correctness of systems-level code running in production.
• Collaborate with open-source maintainers and engineering teams to improve tooling and ecosystem support.
• Investigate deep infrastructure bugs across boundaries (C++, proxies, OS, network stack).
• Contribute to shaping our telemetry standards and cross-platform instrumentation strategies.

Who You Are: 

• You’ve written performant, production-grade C++ (C++14 or later) in complex systems.
• You’re confident with multithreading, memory management, and debugging low-level concurrency bugs.
• You’re comfortable owning critical paths in systems that need to be fast, observable, and safe under load.
• You communicate clearly and thrive in remote, distributed, or async-first teams.

Bonus points:

• You’ve worked on or contributed to open-source reverse proxy projects.
• You’ve built or maintained developer-facing libraries or SDKs.
• You have experience working on infrastructure components such as proxies, load balancers, or gateway layers.
• You’re familiar with system-level observability tools (perf, eBPF, systemtap, etc.).
• You’ve debugged performance bottlenecks in HTTP, TLS, or TCP/IP stacks.
• You have exposure to distributed systems and service meshes at scale.

Datadog values people from all walks of life. We understand not everyone will meet all the above qualifications on day one. That's okay. If you’re passionate about technology and want to grow your skills, we encourage you to apply. 

Benefits and Growth: 

• New hire stock equity (RSUs) and employee stock purchase plan (ESPP)
• Continuous professional development, product training, and career pathing
• Intradepartmental mentor and buddy program for in-house networking
• An inclusive company culture, ability to join our Community Guilds (Datadog employee resource groups)
• Access to Inclusion Talks, our Internal panel discussions
• Free, global mental health benefits for employees and dependents age 6+
• Competitive global benefits

Benefits and Growth listed above may vary based on the country of your employment and the nature of your employment with Datadog.