# Senior Software Engineer - Security Libraries

**Company:** [Datadog](https://hotfix.jobs/companies/datadog)
**Location:** Bordeaux, France, Lyon, France, Madrid, Spain, Nantes, France, Paris, France, Sophia Antipolis, France, Lisbon, Portugal
**Role:** Backend Engineering
**Experience:** 5+ years
**Skills:** .Net, C#, Java, Go, Node.js, Python, Ruby, PHP, C++, Waf, Rasp, Api Security, Iast, Sca, Kubernetes
**Posted:** 2026-08-12

> Senior engineer building and operating security integrations and detection capabilities across Datadog’s polyglot libraries. The role requires deep .NET or Java expertise, experience shipping developer-facing libraries or SDKs, strong performance and operational skills, and a product-oriented mindset.

## Job Description

## Responsibilities
- Design, build, and own security integrations and detections, including WAF, RASP/exploit prevention, API Security, IAST, and SCA, across multiple libraries, with .NET and/or Java as the primary focus.
- Take projects from prototype to deployed, correct, operable, and maintainable, writing code that safely instruments thousands of applications in production.
- Monitor production telemetry, including WAF/RASP timeouts, performance, and cost; debug cross-system issues and reduce customer-facing problems.
- Help define OKRs, break features into components, and drive designs and RFCs to alignment across security library teams.
- Partner with product management, backend, and frontend teams to turn product ideas, new detections, agentic onboarding, and API security into adopted customer capabilities.
- Mentor teammates, improve code quality and testing, and increase team effectiveness.
- Represent Datadog in relevant language and security communities.

## Requirements
- Expert knowledge of at least one of .NET (C#) or Java, with the ability to contribute idiomatically across other libraries.
- Strong software engineering fundamentals and experience shipping modular, maintainable, well-tested, performant code.
- A product-engineering mindset focused on user experience and product outcomes.
- Experience building and shipping libraries or SDKs consumed by other developers, including packaging, versioning, and backward compatibility.
- Experience measuring and optimizing performance and cost.
- Operational maturity and accountability for production systems.
- Clear written and verbal communication, including driving alignment through RFCs and collaboration.
- BS, MS, or PhD in a STEM field, or equivalent experience.

## Nice-to-haves
- Deep expertise in .NET or Java runtime internals and instrumentation, including the JVM, bytecode instrumentation, Java agents, CLR/JIT/GC, IL rewriting, or DiagnosticSource/EventPipe.
- Experience shipping across Go, Node.js, Python, Ruby, PHP, or C/C++.
- Application security experience with WAF, RASP, SAST/IAST/SCA, threat detection, or secure-by-design practices.
- Experience with auto-instrumentation, APM/distributed tracing, code telemetry, or introspection.
- Experience maintaining open-source projects or publishing packages such as NuGet or Maven packages.
- Experience with AI-assisted developer tooling or agentic workflows.
- Developer-experience or customer-support sensibility.

## Compensation and Benefits
- No compensation information provided.

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