About the job

Software Engineer — Agent Guardrails

Location: Germany (Remote)Company: Early-Stage Cybersecurity Startup

A well-funded cybersecurity startup founded by experienced security entrepreneurs is hiring a Software Engineer to own its language-runtime sensors. The company is fundamentally changing application security by moving organizations away from reactive vulnerability management toward proactive, real-time protection at the runtime level.

In this role, you will build the instrumentation layer that hooks directly into key packages, generating real-time events for the core policy engine to monitor and block malicious AI agent behavior as it happens.

• What You Will OwnSensor Architecture: Design and build low-latency runtime instrumentation across Node.js and Python to track AI agent execution paths in real time.
• Ecosystem Expansion: Pioneer hooks and interceptors for emerging protocols (such as MCP), LLM SDKs, web frameworks, and new execution transports.
• Proactive Adaptation Systems: Engineer automated systems and harness tooling to detect, test, and automatically surface upstream SDK shifts before they impact runtime behavior.
• Performance Optimization: Enforce strict execution overhead budgets to ensure guardrails never compromise host agent execution speed.

• What You NeedProduction Mastery (Node.js & Python): Proven experience with dynamic module loading, monkey-patching, and low-level runtime interception across both ecosystems.
• Systems & FFI Fundamentals: Strong background bridging managed runtimes into compiled binaries (Rust, C, C++), alongside a solid grasp of memory management, thread safety, and dynamic linking.
• Async Execution Expertise: Deep understanding of non-blocking control flow (Node event loop, Python asyncio) to ensure security hooks never block host applications.
• Resilient System Design: Track record of building stable software on top of fast-evolving third-party SDKs and uncooperative runtimes.
• Diagnostic Mindset: Natural ability to hunt down race conditions, memory leaks, and silent failures across runtime boundaries.