Senior Software Engineer - AI Agents Testing

At Zendesk, we're on a mission to build the most advanced AI agents in CX, and the AI Agent Testing team within the AI Agents organization plays a critical role in ensuring those agents are reliable, robust, and ready to deliver real customer value. Our focus is on synthetic testing, evaluation workflows, validation frameworks, and tooling that help us measure quality, uncover failure modes, and ship with confidence.

As a Senior Fullstack Engineer on this team, you'll be a key technical contributor shaping the systems, tooling, and workflows that power AI agent evaluation at scale. While this is a fullstack role, it leans more on backend development as we're looking for someone who is deeply comfortable with APIs, event-driven systems, testing infrastructure, data workflows, and platform thinking , while also being able to design and deliver polished user-facing tools when needed.

You'll collaborate closely with product managers, designers, data engineers, applied AI/ML partners, and fellow engineers to build internal and customer-facing capabilities that improve the quality of our AI agents. In this role, you'll not only ship features end-to-end, but also help shape technical direction, raise the bar on engineering quality, and influence how the team solves complex problems.

Your work will directly impact how Zendesk validates and improves its AI agents, helping ensure our products are trustworthy, measurable, and effective., * You consistently deliver high-quality work on complex, ambiguous problems with minimal guidance.

• You raise the technical bar through thoughtful architecture, strong testing practices, and reliable system design.
• You help the team make better technical decisions by identifying tradeoffs and proposing pragmatic solutions.
• You contribute to the reliability, scalability, and observability of the systems the team owns.
• You collaborate effectively across product, design, AI/ML, and data, and help align stakeholders around technical direction.
• You mentor and support other engineers through code reviews, design discussions, and day-to-day collaboration.
• You demonstrate strong ownership by driving work forward, surfacing risks early, and helping the team execute with confidence.

Our Tech Stack

• Frontend : TypeScript, React
• Backend : Node.js (ES7+), TypeScript, MongoDB, Snowflake
• Infrastructure : AWS, Kubernetes, Terraform, ArgoCD, Sentry, Redis, Datadog, GitHub Actions

• 5+ years of experience building modern web applications using TypeScript, React, and Node.js .
• Strong experience designing and building backend services, APIs, and event-driven systems .
• Strong understanding of software engineering best practices, including clean architecture, testing strategy, observability, and maintainability .
• Experience working across the stack and delivering polished, performant, accessible user experiences.
• Ability to independently drive complex projects from ambiguity to execution, while partnering effectively across functions.
• Excellent communication skills , proactive mindset and the ability to influence technical decisions, align stakeholders, and mentor other engineers.
• You are a product-minded engineer , you care deeply about the end-user experience and proactively contribute ideas to improve product outcomes.
• Comfort working in fast-moving, cross-functional environments and iterating based on feedback.
• A drive for continuous learning, reflection, and improvement, in both your own growth and your team's success.
• You are eager to expand into ML engineering and learn how it connects to evaluation, testing, and the lifecycle of AI systems., * Are familiar with AWS, and comfortable with CI/CD pipelines.
• Have a good understanding of microservice architecture, event-driven systems, and relational/NoSQL data modeling .
• Have experience with AI agentic tools such as Cursor , Claude Code , and similar developer assistants.
• Have experience with Python , especially for testing, automation, data processing, or scripting.
• Have prior experience building evaluation systems, synthetic testing pipelines, or AI quality tooling.

Zendesk software was built to bring a sense of calm to the chaotic world of customer service. Today we power billions of conversations with brands you know and love. Zendesk believes in offering our people a fulfilling and inclusive experience. Our hybrid way of working, enables us to purposefully come together in person, at one of our many Zendesk offices around the world, to connect, collaborate and learn whilst also giving our people the flexibility to work remotely for part of the week.