Senior Machine Learning Engineer, On-Device & Mobile AI Optimization

The opportunity
We are building the next generation of AI-driven game experiences, running generative models on-device, right where the players are — on phones, tablets, laptops, and desktops. Our games run inside a modern, browser-native runtime (built on technologies such as WebGPU and WebNN), so the models that power these experiences must be deployed and accelerated entirely within that runtime. As a Senior Machine Learning Engineer for On-Device & Mobile AI, you will take state-of-the-art multi-modal models — transformers, diffusion networks, and vision-language models (VLMs) — and make them run fast, small, and reliably on mobile and constrained hardware.

This is a deeply hands-on role. You will own the optimization and deployment of significant parts of the inference stack — from a trained checkpoint leaving research, through export, quantization, and kernel-level tuning, to a shipped feature running inside the engine at interactive frame rates within a fixed memory and power budget. Your work directly shapes the latency, quality, memory footprint, and battery profile of AI features experienced by billions of players.

This role is for an engineer who is energized by the gap between a research model and a shipping, on-device product. If you enjoy profilers, frame captures, op-fusion, and shaving milliseconds and megabytes, this is your role.

What you'll be doing

• Inference & On-Device Optimization
• Own the optimization pipeline for the models you ship: model export, graph transformation, operator fusion, memory-layout planning, and hardware-specific tuning across NPU, mobile GPU, and desktop/laptop GPU.
• Apply quantization (INT4/INT8/FP16), weight sharing, structured/unstructured pruning, and knowledge distillation to hit hard latency, memory, and power budgets — and validate them against quality bars.
• Do low-level performance work: write and tune WebGPU compute shaders (WGSL) and, where relevant, native kernels (Metal, Vulkan/SPIR-V compute, CUDA); profile with browser and platform tools (Chrome/Dawn GPU traces, PIX, Instruments/Metal System Trace,
• Snapdragon Profiler, Nsight, RenderDoc), and eliminate bottlenecks at the op and memory-bandwidth level.
• Apply efficiency techniques — dynamic resolution, token reduction, cross-frame caching/reuse, reduced-step diffusion samplers — as engineering levers to meet budgets on target SKUs.
• Runtime & Systems Integration
• Work with WebGPU-targeted inference runtimes (ONNX Runtime Web, Transformers.js, WebLLM, TensorFlow.js) alongside native options (CoreML, ONNX Runtime, TFLite, ExecuTorch), and extend or build glue code where off-the-shelf options fall short of our diffusion and VLM workloads.
• Build parts of the integration between the ML runtime and the game engine: real-time scheduling, memory pooling, zero-copy buffer sharing between the inference and render paths, and frame-budget management alongside the renderer.
• Build supporting engineering for your components: model packaging and asset pipelines, on-device fallbacks and SKU-aware capability tiers, crash/quality telemetry, and automated on-device benchmarking in CI.
• Research Productionization
• Partner with research scientists to turn novel CV and multi-modal architectures into implementations that are deployable, debuggable, and fast on device.
• Provide a feedback loop into research: surface hardware constraints, op-support gaps, and cost models early so model design and deployment converge.
• Track breakthroughs in efficient inference (efficient attention, distillation, reduced-step diffusion) and assess them pragmatically: what actually moves latency/memory/power on our target devices.
• Collaboration & Engineering Quality
• Contribute to engineering best practices, code-review standards, performance-regression gates, and on-device benchmarking methodology.
• Support a culture of measurement: track KPIs for latency, quality, memory, and power for the systems you work on, across the device matrix.
• Partner with platform engineers, product managers, and runtime teams to align your work with device-SKU constraints and product roadmaps.
• Share knowledge and mentor junior and mid-level engineers through code review, pairing, and design discussion.

What we're looking for

• 5+ years in software/ML engineering, with meaningful time focused on on-device / edge inference or real-time, performance-critical systems.
• Production deployment of transformer- and/or diffusion-based models (e.g., ViT, Stable Diffusion, CLIP/SigLIP-style encoders) on mobile, desktop, or embedded hardware — shipped, not just prototyped.
• Hands-on experience with at least one major inference runtime (ONNX Runtime / ORT Web, CoreML, TFLite, ExecuTorch) and a working understanding of operator fusion, memory layout, and runtime scheduling.
• Low-level performance engineering: solid command of at least one GPU/compute API — WebGPU/WGSL, Metal, Vulkan, D3D12, or CUDA — and the profiling tools to go with it.  You can read a frame capture and a kernel trace and reason about where the time and memory go.
• Working knowledge of model-optimization techniques — quantization (INT4/INT8/FP16), weight sharing, pruning, and distillation — and the judgment to apply them to hit latency and memory budgets. You use them effectively as engineering tools.
• Understanding of target hardware: mobile SoCs (Apple Neural Engine, Qualcomm Hexagon/Adreno, ARM Mali) and/or desktop/laptop GPUs (Apple Silicon, NVIDIA, AMD, Intel).
• Strong Python for export pipelines and training-side tooling; familiarity with the core languages of a browser-native runtime (TypeScript/JavaScript, WGSL) is a plus.
• Working fluency with the models you deploy — enough to read an architecture, modify it for deployment, and reason about accuracy trade-offs.
• A collaborative working style: clear communication, reliable delivery, and a willingness to support and learn from teammates.

You might also have

• Experience shipping world-model, neural-rendering, or real-time generative pipelines NeRF, 3DGS, real-time diffusion, or similar) on device.
• Hands-on experience deploying models through WebGPU — e.g., ONNX Runtime Web WebGPU EP), Transformers.js, WebLLM, or TensorFlow.js — including writing/tuning WGSL compute shaders.
• Game-engine or real-time-graphics background (Unity, Unreal, or a custom engine; Metal/Vulkan/D3D/OpenGL ES render pipelines) — especially integrating compute workloads alongside a renderer.
• Contributions to open-source ML inference frameworks, runtimes, or GPU/compute libraries especially in the WebGPU ecosystem (Dawn, wgpu, ORT Web, Transformers.js, WebLLM).
• Familiarity with compiler stacks (MLIR, TVM, IREE, XLA) for custom kernel generation and graph optimization.
• Experience with on-device benchmarking infrastructure, performance-regression CI, and device-farm matrices.
• Proficiency in C++/Objective-C/Swift for runtime integration.

Additional information

• Relocation support is not available for this position
• Work visa/immigration sponsorship 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 www.unity.com.

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.

Pursuant to the San Francisco Fair Chance Ordinance, we will consider for employment qualified applicants with arrest and conviction records.

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.

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