Senior AI Engineer

Senior AI EngineerSan Francisco Bay Area, CAWhy Weave ExistsAt Weave, our mission is to evolve how therapeutic knowledge is captured, transformed, and communicated throughout drug development. We do this by equipping human experts with AI instruments to enable drugs to be brought to patients as rapidly, safely, and inexpensively as possible.The Weave Platform streamlines regulatory workflows from start to finish by intelligently, creatively, and effectively infusing every step with AI. Together with our customers, Weave is designing and building the AI workbench for the entire therapeutic lifecycle.The Role & Your MissionWe're seeking a hands-on Senior AI Engineer who can bridge the gap between data and biomedical expertise while delivering robust backend code. Reporting to the Head of Applied AI, your primary focus will be building the LLM-facing components of our backend service, while ensuring the AI models consistently produce accurate, grounded, useful, and reliable outputs under real-world load.The ideal candidate thrives in the full development cycle: taking concepts from initial conception through rigorous experimentation and testing, all the way to production deployment. You won't get lost in low-ROI side quests, but instead will maintain velocity with unwavering focus on the core value of your tasks.We value pragmatic problem-solving over flashy technology and buzz words, robustly tested solutions over demoware. We're building solutions that actually work—simple, thoroughly tested, and rock-solid reliable. If you believe the best technology is the one that consistently delivers results, you'll fit right in.What You'll OwnWriting production-ready backend code for LLM-facing components of our backend serviceBuilding automated evaluation systems for LLM-dependent code, including regression datasets, quality metrics, failure taxonomies, and release gatesDesigning and validating LLM-based solutions (prompts, context-construction pipelines, tool-calling workflows, structured outputs, and retrieval systems) and proving their effectiveness with real data and meaningful metricsMeasuring and improving LLM solutions quality, grounding, consistency, latency, token usage, and costWhat You'll BringDirect experience building, shipping and operating meaningful LLM-powered products or workflows in productionScientific or quantitative background in machine learning, statistics, computer science, biology, chemistry, or a related field; experience in biotech, pharmaceuticals, or another life-sciences setting is preferredHumble, hungry, and smart attitudeAbility to move quickly while maintaining a high bar for correctness and reliabilityClear technical judgment: able to explain trade-offs, prioritize high-value work, and stop low-ROI experimentationBonus: