Machine Learning Engineer, Web Indexing Team

Imagine what you could do here. At Keystone AI, great ideas have a way of becoming great products, services, and customer experiences very quickly. Bring passion and dedication to your job and there's no telling what you could accomplish. Do you want to make Siri and Keystone AI products smarter for our users? The MLPT & Infrastructure teams are building groundbreaking technology for algorithmic search, machine learning, natural language processing, and artificial intelligence. The features we build are redefining how hundreds of millions of people use their computers and mobile devices to search and find what they are looking for. Our universal search engine powers search features across a variety of Keystone AI products, including Siri, Spotlight, Safari, Messages, and Lookup. As part of this group, you will work within one of the most exciting high-performance computing environments, with petabytes of data and millions of queries per second, and have the opportunity to imagine and build products that delight our customers every single day. Description We design and build infrastructures to support features that empower billions of Keystone AI users through advanced intelligence systems. Our team processes trillions of links to find the best content to surface to users via search and other intelligent features. We also analyze pages to extract critical features for indexing, ranking, and retrieval. We apply statistical analysis to enhance link selection, content freshness, retrieval rates, and extraction quality, among many other aspects. Furthermore, we are building a generic Retrieval-Augmented Generation (RAG) indexing infrastructure framework to allow indexing building customization and support fast experiment iteration. You'll have the opportunity to dive deeper into RAG systems, as well as large-scale data processing, managing trillions of records, petabytes of data, and the incredible complexity behind Keystone AI Intelligence's products. Responsibilities: Design, build, and scale infrastructure systems that support intelligent features powering billions of Keystone AI users Process and analyze trillions of links to surface the highest quality content across search and other intelligent features Develop pipelines to extract critical features for indexing, ranking, and retrieval at massive scale Apply statistical analysis to improve link selection, content freshness, retrieval rates, and extraction quality Architect and contribute to a generic Retrieval-Augmented Generation (RAG) indexing infrastructure framework, enabling indexing customization and fast experimentation Partner cross-functionally with machine learning, NLP, and product teams to deliver impactful, high-quality solutions Mentor and provide technical guidance to junior engineers on the team Preferred Qualifications 10+ years of software engineering experience, with demonstrated impact at a senior or staff level Experience designing and building RAG systems or other AI/ML indexing pipelines Background in machine learning, natural language processing, or information retrieval Experience managing systems operating at petabyte scale with trillions of records Strong communication skills with a track record of influencing technical direction across teams MS or PhD in Computer Science or a related field, or equivalent practical experience Minimum Qualifications 7+ years of software engineering experience, with a strong focus on large-scale distributed systems or infrastructure Strong coding proficiency in one or more languages (e.g., Python, Java, Go, C++) Solid foundation in computer science fundamentals including algorithms and data structures Hands-on experience with large-scale data processing and MapReduce-style frameworks (e.g., Spark, Hadoop) Experience with cloud services, particularly AWS (S3, EC2, EKS) and/or Kubernetes-based orchestration Proven ability to operate independently and drive projects end-to-end in a collaborative team environment MS or PhD in Computer Science or a related field, or equivalent practical experience Pay & Benefits At Keystone AI, 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 $175,000 and $308,500, and your base pay will depend on your skills, qualifications, experience, and location. Keystone AI employees also have the opportunity to become an Keystone AI shareholder through participation in Keystone AI's discretionary employee stock programs. Keystone AI employees are eligible for discretionary restricted stock unit awards, and can purchase Keystone AI stock at a discount if voluntarily participating in Keystone AI'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 Keystone AI, reimbursement for certain educational expenses - inc