Machine Learning Engineer - LLMs, Agent Systems, and Simulation Tooling, Siri Core Modeling

Apple’s Siri organization is seeking a Senior Machine Learning Engineer to advance next-generation intelligent agents for natural voice and multimodal experiences. This role focuses on scalable LLM reasoning systems, agent-based simulation and evaluation tooling, and the integration of agent behaviors across client and backend environments.

Role Focus

In this position, you will define and build foundations for how intelligent agents reason, plan, and interact with people. The work centers on developing robust infrastructure for training, running experiments in simulated environments, and creating scalable evaluation pipelines to support agentic voice experiences.

Responsibilities

• Design and implement scalable simulation and evaluation frameworks for LLM-based agents
• Collaborate with ML researchers to translate novel reasoning approaches into production-grade systems
• Develop infrastructure for training and experimentation with agentic behaviors
• Integrate agent reasoning capabilities into client-side and backend environments
• Drive iteration speed by creating reliable tooling for experimentation, prototyping, and deployment

Key Contributions

• Build core reasoning and simulation capabilities that support a future platform for agentic voice experiences
• Advance how LLMs plan, adapt, and evaluate actions in realistic environments
• Contribute to reliable and trustworthy AI agent development
• Design and run experiments in simulated environments
• Help integrate agent behaviors across client and backend systems
• Collaborate with ML scientists, applied researchers, and product engineers to move early research into deployable systems
• Shape a platform that supports developers and end-users building rich, voice-driven AI experiences

Required Qualifications

• Experience deploying LLM models in research or production contexts
• Knowledge of adaptive feedback loops, reinforcement learning, or interactive agent design
• Familiarity with client-backend integration for AI-driven applications
• MS or PhD in Computer Science, Machine Learning, or a related field
• Bachelor’s degree in Computer Science, Machine Learning, or a related quantitative field, with 3+ years of relevant industry experience
• Strong skills in Python (preferred) and at least one other programming language
• Proven ML engineering experience, including system design, training pipelines, and deployment workflows
• Deep understanding of agent-based simulation, agentic RAG systems, and LLM evaluation methodologies
• Ability to balance long-term platform vision with pragmatic short-term delivery in fast-paced environments

Technologies

• Python
• Reinforcement learning
• Agentic RAG systems
• LLM evaluation methodologies

Education

Bachelor’s degree in Computer Science, Machine Learning, or related quantitative field.

Location

Cupertino, CA (onsite)

Pay

Base pay range for this role is USD 150,400 - 277,600 per year, determined within a range based on skills, qualifications, experience, and location.

Benefits

• Comprehensive medical and dental coverage
• Retirement benefits
• A range of discounted products and free services
• Reimbursement for certain educational expenses, including tuition
• Opportunity to become an Apple shareholder through participation in Apple’s discretionary employee stock programs
• Eligible for discretionary restricted stock unit awards
• Can purchase Apple stock at a discount if voluntarily participating in Apple’s Employee Stock Purchase Plan
• Additionally, this role might be eligible for discretionary bonuses or commission payments as well as relocation

Note: Apple benefit, compensation, and employee stock programs are subject to eligibility requirements and other terms of the applicable plan or program.