xAI

Model Engineer, Multimodal Understanding

xAI
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2 days ago
Palo Alto, CA, USASenior
H1B sponsor

Base Salary

$160k - $250k/yr

Responsibilities

  • Design, build, and optimize distributed systems for multimodal pre-training, post-training, inference, data processing, and tokenization at web and petabyte scale.
  • Develop high-throughput pipelines for multimodal data acquisition, preprocessing, filtering, generation, decoding, loading, crawling, visualization, and management.
  • Advance multimodal understanding and generation, including spatial-temporal compression, cross-modal alignment, world modeling, reasoning, real-time video processing, and noisy-data handling.
  • Drive human and synthetic data curation, filtering, quality analysis, and scalable data pipelines for large models.
  • Create evaluation frameworks, benchmarks, reward models, and metrics for real-world usage, failure modes, interactive dynamics, and human-AI collaboration.
  • Innovate on algorithms, modeling, hardware/software/algorithm co-design, and scaling approaches.
  • Build research tooling, interfaces, prototypes, demos, full-stack applications, and real-time interactive experiences.
  • Work across pre-training, supervised fine-tuning, reinforcement learning, and post-training to enable reasoning, tool calling, agentic behavior, orchestration, and real-time interaction.

Requirements

  • Production-quality coding experience in Python, PyTorch, JAX, Rust, or C++.
  • Expert-level Python proficiency and strong experience with at least one of JAX, PyTorch, or XLA.
  • Experience building or optimizing large-scale distributed ML systems, including training or inference optimization, GPU utilization, multi-GPU or TPU setups, and hardware co-design.
  • Deep experience designing and operating large-scale data pipelines for curation, filtering, generation, and quality studies involving noisy, real-world multimodal data.
  • Strong fundamentals in evaluation design, benchmarking, reward modeling, or reinforcement learning, especially for interactive or agentic behaviors.
  • Experience leading major model-capability improvements through data, modeling, algorithms, or scaling.
  • Familiarity with multimodal LLMs, scaling laws, tokenizers, compression techniques, reasoning, or agentic systems.
  • Proficiency in Rust and/or C++ for performance-critical components.
  • Hands-on experience with large-scale orchestration tools such as Spark, Ray, or Kubernetes.
  • Experience building full-stack tooling, performant interfaces, real-time research demos or applications, or end-to-end products.
  • Passion for interactive, real-time multimodal AI systems and willingness to own end-to-end initiatives in a high-intensity environment.

Benefits

  • $160,000–$250,000 base salary.
  • Equity, comprehensive medical, vision, and dental coverage, access to a 401(k) retirement plan, short- and long-term disability insurance, life insurance, discounts, and other perks.
xAI

About xAI

1,001-5,000 employees

Understand the Universe. We are a team of AI technologists and business leaders on a mission to build AI systems that can help humanity understand the world better. https://x.ai/careers

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