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

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.

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.

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 tests for agent workflows, including failure injection and resilience testing.

Manual and Exploratory Testing

• Perform hands‑on exploratory testing of agent behavior, including new capabilities, ambiguous or under specified requests, long multi‑turn sessions, and unusual operational scenarios that scripted tests don’t anticipate.

• Manually review agent traces and outputs to judge reasoning quality, appropriateness of actions, and safety, and use those findings to improve automated checks.

• Execute manual regression and release verification passes in staging and customer‑like environments before new agent capabilities ship.

• Conduct manual red‑teaming sessions (prompt injection, jailbreaks, tool misuse, unsafe actions) in partnership with security teams, then convert successful attacks into automated test cases.

• Support user acceptance testing and pilot rollouts with Forward Deployed Engineers, capturing real‑world failures and feeding them back into test suites.

• Write clear test plans, test charters, and bug reports, and maintain manual test documentation where automation isn’t yet practical or cost‑effective.

Datasets, Metrics, and Quality Strategy

• Create and manage golden datasets and labeled test sets, including edge cases, ambiguous inputs, and adversarial prompts specific to industrial and operational contexts, with tooling for versioning and drift detection.

• Design rubrics and run human‑in‑the‑loop evaluations where automated scoring isn’t reliable enough.

• Define and instrument quality metrics beyond simple accuracy (groundedness, hallucination rate, task success rate, latency/cost tradeoffs, and safety violations) and build dashboards to track them over time.

• Test agent behavior across the full action loop (planning, tool selection, tool execution, error recovery, and…