Principal Machine Learning Engineer, Mobile AI Inference Optimization

Mountain View, CA, USA

Principal Machine Learning Engineer, Mobile AI Inference Optimization

Location

Mountain View, CA, USA

Department

AI & Machine Learning

Requisition ID

JOBREQ-2615941

Role description

The opportunity

We are building the next generation of mobile game AI experiences, deploying world models to mobile on-device. As our Principal Machine Learning Engineer, you will be the foremost technical authority on bringing state-of-the-art multi-modal models (transformers, diffusion networks, and JAPE-style architectures) from research to production on mobile hardware.

This is a deeply hands-on, high-impact role. You will define the inference strategy, drive architectural decisions across the full mobile ML stack, and mentor a team of senior and mid-level engineers. Your work will directly determine the latency, quality, and power profile of AI-driven features experienced by billions of mobile game players.

What you'll be doing

• Technical Leadership:

• Set the technical vision and roadmap for deploying multi-modal AI models to iOS and Android, spanning transformers, diffusion models, and JAPE-style generative architectures.

• Make authoritative decisions on model compression, quantization, pruning, and knowledge distillation strategies to meet mobile latency and memory budgets.

• Evaluate and select inference runtimes (e.g., CoreML, ONNX Runtime Mobile, TFLite, ExecuTorch) and drive adoption across the team.

• Own the end-to-end optimization pipeline: from model export and graph transformation to hardware-specific kernel tuning on NPU, GPU, and CPU.

• Architecture & Research Translation:

• Collaborate directly with research scientists to translate novel model architectures into deployable, mobile-optimized implementations.

• Design scalable systems for multi-modal inference that process diverse inputs - images, text, primitives, and metadata - and produce pixel-level outputs with real-time performance.

• Pioneer new approaches to dynamic resolution, token reduction, and speculative decoding tailored to mobile constraints.

• Track and rapidly adopt breakthroughs in efficient diffusion (e.g., consistency models, flow matching) and efficient attention (e.g., FlashAttention, linear attention variants).

• Team & Cross-Functional Leadership:

• Lead and mentor a team of ML engineers; define engineering best practices, code review standards, and on-device benchmarking methodology.

• Partner with platform engineers, product managers, and runtime teams to align ML capabilities with device SKU constraints and product roadmaps.

• Champion a culture of measurement: define KPIs for latency, accuracy, memory, and power consumption and ensure the team tracks them rigorously.

What we're looking for

• 8+ years in ML engineering, with at least 3 years focused on on-device / edge inference optimization.

• Proven production deployment of transformer-based models (e.g., ViT, LLaMA, Stable Diffusion) and/or JAPE-style generative architectures on mobile or embedded hardware.

• Hands-on expertise with CoreML, TFLite, ONNX Runtime, and/or ExecuTorch; deep understanding of operator fusion, memory layout, and runtime scheduling.

• Expert-level command of INT8/INT4/FP16 quantization, weight sharing, structured/unstructured pruning, and knowledge distillation.

• Strong understanding of mobile SoC architectures (Apple Neural Engine, Qualcomm Hexagon/Adreno, ARM Mali) and how to target each for peak throughput.

• Proficiency in C++ / Objective-C / Swift for runtime integration; solid Python for training-side tooling and export pipelines.

• Ability to read, implement, and extend ML research papers; familiarity with efficient attention, diffusion samplers, and multi-modal fusion techniques.

• Track record of technical leadership: setting direction, influencing cross-functional partners, and growing engineers.

You might also have

• Experience shipping world-model or neural rendering pipelines (NeRF, 3DGS, or similar) on mobile.

• Contributions to open-source ML inference frameworks or mobile ML research publications.

• Familiarity with compiler stacks such as MLIR, TVM, or XLA for custom kernel generation.

• Background in real-time graphics or game engine pipelines (Metal, Vulkan, OpenGL ES).

Additional information

• International relocation support is not available for this position

Benefits

At Unity, we want our team members to thrive. We offer a wide range of benefits designed to support well-being and work-life balance.

Please note: Benefits eligibility, specific offerings, and coverage vary based on the country and employment status.

While specific benefits vary, here are some of the ways we strive to take care of our eligible team members globally: Comprehensive health, life, and disability insurance | Commute subsidy | Employee stock ownership | Competitive retirement/pension plans | Generous vacation and personal days | Support for new parents through leave and family-care programs | Office food snacks | Mental Health and Wellbeing programs and support | Employee Resource Groups | Global Employee Assistance Program | Training and development programs | Volunteering and donation matching program

Life at Unity

Unity [NYSE: U] is the world's leading game engine, powering play for more than 3 billion consumers each month. The top mobile games in the world, the most played PC indie titles, the most innovative console games, and virtually all of the top XR and Web Games are developed, deployed, and grown in Unity. Unity also enables teams across industries like automotive, manufacturing, and healthcare to design, simulate, and collaborate in 3D - closing the gap between ideas and reality. For more information, please visit

Unity is a proud equal opportunity employer. We are committed to fostering an inclusive, innovative environment and celebrate our employees across age, race, color, ancestry, national origin, religion, disability, sex, gender identity or expression, sexual orientation, or any other protected status in accordance with applicable law. Our differences are strengths that enable us to support the growing and evolving needs of our customers, partners, and collaborators. If you have a disability that means there are preparations or accommodations we can make to help ensure you have a comfortable and positive interview experience, please fill out this form ( to let us know.

This position requires the incumbent to have a sufficient knowledge of English to have professional verbal and written exchanges in this language since the performance of the duties related to this position requires frequent and regular communication with colleagues and partners located worldwide and whose common language is English.

Headhunters and recruitment agencies may not submit resumes/CVs through this website or directly to managers. Unity does not accept unsolicited headhunter and agency resumes. Unity will not pay fees to any third-party agency or company that does not have a signed agreement with Unity.

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*Note: This range reflects the anticipated base salary for this position. Beyond base salary, this role may be eligible for equity awards and participation in our company incentive plans (such as annual discretionary bonuses or sales commissions). The final offer amount will depend on several factors, including geographic location and the candidate's relevant experience, professional background, and skill set.

Gross pay salary

$278,100-$347,600 USD