Tobias FuSan Francisco, CA | 646-744-4902 | [email protected] | tobiasfu.com | GitHub: realtobyfuEducationTufts University Medford, MAB.S. in Computer Science September 2021 – May 2025• Relevant coursework: Machine Learning, Reinforcement Learning, Algorithms, Software Engineering• Independent LLM study with Peter Nadel (Tufts Tisch Data Lab): a weekly reading group from transformer architecturethrough RAG, agentic orchestration, and sparse autoencoders — the research behind Vitals.Experiencesus. San Francisco, CATechnical Co-Founder | Swift, SwiftUI, React Native, TypeScript backend (App Store) May 2026 – Present• Buildingasocialplatformforcandiddatingstorieswithaco-founder: shippingfeaturesonbothReactNativeandnativeiOS — especially iOS — and maintaining the TypeScript backend.• Leading the port to Swift/SwiftUI: rethinking navigation and interactions for iOS rather than transliterating the ReactNative prototype (kept for Android).• Shape moderation policy for a sensitive social space; integrated Sentry + PostHog monitoring and analytics.Vybes App Inc. RemoteiOS / Full-Stack Developer | Swift, SwiftUI, NestJS, TypeScript, Redis, AWS February 2025 – June 2025• Updated the membership onboarding features of an iOS dating app serving 1,000+ users ahead of its marketingpush — new SwiftUI views alongside the original UIKit codebase.• Improved the matching algorithm and fixed bugs across the matching and video-call flows (Agora SDK); worked onthe NestJS/Redis backend.Develop for Good RemoteSoftware Engineer Intern | React, TypeScript, Node, SQL May 2024 – August 2024• Ledacross-functionalteamof 7 engineersbuildingawebapplicationfor500+ therapists;droveAPIdesign,databaseschema decisions, and feature prioritization.Projects (case studies at tobiasfu.com/projects)Commonplace | TypeScript, Next.js, Postgres/pgvector, Temporal, Groq (live demo) 2026• Along-contextAIworkspacethatmakesamodel’sworking memory visible and steerableovera1.75M-wordcorpus:watch context assemble as answers stream, pin what matters, and click any claim through to the exact passage inmemory.• Durable ingestion via a Temporal workflow with idempotent steps — tested against worker restarts; standing evals forfaithfulness, retrieval, and routing.Vitals | Python, Next.js, Gemma Scope SAEs (live demo) 2026• A real-time LLM interpretability instrument: streams a model’s internal SAE features (sycophancy, user distress,crisis) token by token; steering runs as a controlled experiment whose negative results get published.• Feature funnel: contrastive mining across 16,384 features, cross-validated against Neuronpedia; flagship crisis featureseparates crisis from mundane messages at AUROC 0.96.ProustGPT | Python, FastAPI, LangChain, Pinecone, Cohere (live, open source) 2024 – Present• Redesignedasingle-flowRAGchatbotover12,544bilingualpassagesintoa two-mode product—separatetoolbudgetsand endpoints, with a complexity router choosing between fast RAG (∼2–3s) and a ReAct agent (∼5–15s).• Retrieval measured on a hand-reviewed gold set (111 questions, held-out test split): Recall@5 0.82, MRR 0.69, p50551 ms — including a variant that beat baseline in tuning, regressed on held-out, and is reported anyway.Grove | Swift, SwiftUI, AppKit, SwiftData (App Store) 2026 – Present• AI knowledge workspace for macOS & iOS, largely built by an autonomous agent loop run against specs I wrote —nothing landed unless it built. iOS port: 28 commits in ∼3 hours. Presented at CocoaHeads SF (Mar 2026).• Also shipped solo: Fieldnote (on-device CoreML plant ID), Clockwise (Screen Time API focus timer),Write-It-Down — all on the App Store.Technical SkillsAI engineering: RAG pipelines, embeddings, agentic orchestration (LangChain/ReAct), eval design, SAE interpretability,agent-driven development workflowsWeb & backend: TypeScript, React, Next.js, Node/NestJS, Python, FastAPI, Postgres/pgvector, Redis, Temporal, AWS,Docker, CI/CDApple platforms: Swift, SwiftUI, AppKit, SwiftData/CoreData, Swift Concurrency (async/await, actors), CoreML/Vision,Screen Time API, App Store lifecycleBeyond CodeWWOOF — volunteer farmer (June 2025 – April 2026): organic farms in England, France, New Hampshire, Maine, andHawaii, weeding, tilling, harvesting vegetables and fruit, caring for animals, shipping the projects above from the road.