Machine Learning Engineer II – San Francisco, CA

Job Description
*Machine Learning Engineer II (GenAI & LLM Infrastructure)
Location: San Francisco (Hybrid)*
Zendesk's people have one goal in mind: to make Customer Experience better. Our products help more than 125,000 global brands (AirBnb, Uber, JetBrains, Slack, among others) make their billions of customers happy, every day.

The AI/ML Platform team is at the forefront of this mission. We build the foundation that powers every AI-driven experience at Zendesk, enabling product teams to build, evaluate, and deploy state-of-the-art Large Language Model (LLM) applications reliably and at scale.

We're looking for an ML Engineer II to help design, implement, and improve core components of Zendesk's GenAI infrastructure — from LLM Proxy and evaluation frameworks to orchestration tools for AI agents. You'll work alongside senior engineers and technical leads, contributing to systems that are safe, scalable, and developer-friendly.

This is a hands-on engineering role with significant growth potential, ideal for someone with solid ML engineering skills who wants to deepen expertise in LLM systems and GenAI infrastructure.

What You Get To Do Every Day

• Contribute to the development of Zendesk's LLM Proxy, enabling secure, cost-optimized access to multiple foundation models.
• Help develop and maintain benchmarking and A/B testing frameworks for measuring LLM performance, latency, and cost.
• Assist in building orchestration systems that enable multi-step, tool-using AI agents.
• Work closely with applied ML, product, and platform teams to ensure infrastructure meets product needs.
• Deliver well-tested, maintainable, and performant code ready for production deployment.

What You Bring To The Role

• 2–4 years of hands-on experience developing and deploying ML systems or infrastructure.
• Familiarity with LLM applications, vector databases, or ML/AI infrastructure components.
• Exposure to AWS, GCP, or Azure; understanding of Kubernetes, Docker, or similar containerized environments.
• Proficiency in Python and familiarity with at least one other backend language (Java, Scala, Golang, or Ruby).
• Understanding of CI/CD workflows, testing frameworks, and software design principles.
• Ability to work effectively in cross-functional teams and take feedback constructively.

Preferred Qualifications

• Experience building small-scale ML services or APIs.
• Exposure to ML observability tools and evaluation frameworks.
• Understanding of prompt engineering or fine-tuning workflows for LLMs.

What Our Tech Stack Looks Like

• Our code is written in Python.
• Our servers live in AWS.
• LLM Vendors: OpenAI, Anthropic, Google, Llama
• Infra: Kubernetes, Docker, Kafka, AWS

What We Offer

• Full ownership of the projects you work on.
• What you will be doing will have a huge impact.
• Team of passionate people who love what they do.
• Exciting projects, ability to implement your own ideas and improvements.
• Opportunity to learn and grow.

As part of our commitment to fairness and transparency, we inform all applicants that artificial intelligence (AI) or automated decision systems may be used to screen or evaluate applications for this position, in accordance with Company guidelines and applicable law.

The US annualized base salary range for this position is $110,000.00-$166, This position may also be eligible for bonus, benefits, or related incentives. While this range reflects the minimum and maximum value for new hire salaries for the position across all US locations, the offer for the successful candidate for this position will be based on job related capabilities, applicable experience, and other factors such as work location. Please note that the compensation details listed in US role postings reflect the base salary only (or OTE for commissions based roles), and do not include bonus, benefits, or related incentives.

Hybrid: In this role, our hybrid experience is designed at the team level to give you a rich onsite experience packed with connection, collaboration, learning, and celebration - while also giving you flexibility to work remotely for part of the week. This role must attend our local office for part of the week. The specific in-office schedule is to be determined by the hiring manager.

The Intelligent Heart Of Customer Experience
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.

As part of our commitment to fairness and transparency, we inform all applicants that artificial intelligence (AI) or automated decision systems may be used to screen or evaluate applications for this position, in accordance with Company guidelines and applicable law.

Zendesk is an equal opportunity employer, and we're proud of our ongoing efforts to foster global diversity, equity, & inclusion in the workplace. Individuals seeking employment and employees at Zendesk are considered without regard to race, color, religion, national origin, age, sex, gender, gender identity, gender expression, sexual orientation, marital status, medical condition, ancestry, disability, military or veteran status, or any other characteristic protected by applicable law. We are an AA/EEO/Veterans/Disabled employer. If you are based in the United States and would like more information about your EEO rights under the law, please click here.

Zendesk endeavors to make reasonable accommodations for applicants with disabilities and disabled veterans pursuant to applicable federal and state law. If you are an individual with a disability and require a reasonable accommodation to submit this application, complete any pre-employment testing, or otherwise participate in the employee selection process, please send an e-mail to with your specific accommodation request.