Senior Machine Learning Engineer - Large Language Model (LLM) Development and Optimization

**Sunnyvale, California, United States**

**Machine Learning and AI**

**Summary**

Posted: **Jun 03, 2025**

Weekly Hours: **40**

Role Number: **200607556-3956**

Join Apple’s Software Engineering team, where we push the boundaries of innovation to enhance every Apple product—while safeguarding user privacy and data. We are seeking an experienced machine learning engineer with deep expertise in Large Language Models. As part of the Siri Planner team, you will have the unique opportunity to transform the Siri experience for hundreds of millions of users worldwide.

**Description**

As a Senior Machine Learning Engineer, your mission will be to lead advancements in Siri’s language understanding capabilities using state-of-the-art LLM technologies. Your responsibilities will include:

+ Designing and developing the foundational agentic system that enables Siri to translate natural language queries into tool calls and engage in multi-turn conversations with users.

+ Collaborating with researchers, software engineers, and product designers to integrate AI innovations into Siri’s user experience.

+ Staying at the forefront of research in LLMs, NLP, and AI, and converting cutting-edge advancements into practical, user-facing improvements.If you are passionate about pushing the limits of conversational AI and want to see your work impact millions of users globally, we’d love to hear from you.

**Minimum Qualifications**

+ Advanced degree (MSc/PhD) in Machine Learning, Computer Science, or a related quantitative field; or a BSc with 3+ years of relevant industry experience.

+ Strong proficiency in Python and ML frameworks such as PyTorch and Hugging Face.

+ Proven ability to design and implement scalable ML pipelines, including preprocessing, training, and deployment in production.

+ Excellent problem-solving, analytical, and collaborative skills.

**Preferred Qualifications**

+ Solid understanding of NLP evaluation metrics, with experience benchmarking and optimizing model performance.

+ Hands-on experience building and deploying large-scale machine learning models, particularly in generative AI, LLMs, Retrieval-Augmented Generation (RAG), or agentic systems.

+ Expertise in data generation and augmentation, including synthetic data creation, active learning strategies, and constructing robust datasets for model training.

+ Published research or notable contributions in LLMs, NLP, or AI is highly desirable.

**Pay & Benefits**

At Apple, base pay is one part of our total compensation package and is determined within a range. This provides the opportunity to progress as you grow and develop within a role. The base pay range for this role is between $181,100 and $272,100, and your base pay will depend on your skills, qualifications, experience, and location.

Apple employees also have the opportunity to become an Apple shareholder through participation in Apple’s discretionary employee stock programs. Apple employees are eligible for discretionary restricted stock unit awards, and can purchase Apple stock at a discount if voluntarily participating in Apple’s Employee Stock Purchase Plan. You’ll also receive benefits including: Comprehensive medical and dental coverage, retirement benefits, a range of discounted products and free services, and for formal education related to advancing your career at Apple, reimbursement for certain educational expenses — including tuition. Additionally, this role might be eligible for discretionary bonuses or commission payments as well as relocation.Learn more about Apple Benefits. (https://www.apple.com/careers/us/benefits.html)

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

Apple is an equal opportunity employer that is committed to inclusion and diversity. We seek to promote equal opportunity for all applicants without regard to race, color, religion, sex, sexual orientation, gender identity, national origin, disability, Veteran status, or other legally protected characteristics.Learn more about your EEO rights as an applicant (https://www.eeoc.gov/sites/default/files/2023-06/22-088\_EEOC\_KnowYourRights6.12ScreenRdr.pdf) .

Apple will not discriminate or retaliate against applicants who inquire about, disclose, or discuss their compensation.

Apple participates in the E-Verify program in certain locations as required by law.Learn more about the E-Verify program (https://www.apple.com/jobs/pdf/EverifyPosterEnglish.pdf) .

Apple is committed to working with and providing reasonable accommodation to applicants with physical and mental disabilities. Reasonable Accommodation and Drug Free Workplace policy Learn more .

Apple is a drug-free workplace. Reasonable Accommodation and Drug Free Workplace policy Learn more .

Apple will consider for employment all qualified applicants with criminal histories in a manner consistent with applicable law. If you’re applying for a position in San Francisco, review the San Francisco Fair Chance Ordinance guidelines applicable in your area.

It is unlawful in Massachusetts to require or administer a lie detector test as a condition of employment or continued employment. An employer who violates this law shall be subject to criminal penalties and civil liability.