Senior Software Development Engineer in Test (SDET), QA - AI Systems

About this role

# About Nexxa

Nexxa is building the best AI systems for heavy industries, enabling machines, systems and operations to think, decide and act autonomously across manufacturing, large-scale infrastructure, logistics and legacy environments.

Our mission is to translate deep technical breakthroughs into operational reality, solving some of the hardest systems-level problems in industry.

# Role Overview

We’re looking for a Senior / Staff SDET to own quality for Nexxa’s AI agent systems, combining deep test automation with hands-on manual and exploratory testing. Our agents plan, call tools, and take multi-step actions autonomously in industrial environments. You’ll write production-grade code to build evaluation harnesses, simulation environments, and CI/CD quality gates, and you’ll also get hands-on with the agents yourself: probing behavior, reviewing traces, and validating releases where automation alone can’t judge whether the agent did the right thing.

You’ll work closely with ML engineers, backend engineers, and Forward Deployed Engineers to define what “good” looks like for an agent operating in high-stakes industrial settings, then build and run the systems and processes that measure it continuously.

# Key Responsibilities

Automation and Infrastructure

• Design, build, and maintain test frameworks, evaluation harnesses, and regression suites for LLM-based agents, covering reasoning quality, tool-call correctness, task completion, and multi-turn coherence.
• Build automated pipelines that run evals and test suites on every model, prompt, or tool-integration change, and integrate them into CI/CD as enforceable quality gates.
• Develop simulators, mocks, and sandbox environments for industrial systems and tool APIs so agents can be tested safely, repeatably, and at scale.
• Implement API, contract, integration, and end-to-end tests for the services, tools, and orchestration layers that agents depend on.
• Develop performance, load, and reliability te...