AI Engineer — On-Device Agents & Memory Systems

Phi Browser; San Francisco, Northern (CA, KY); Hybrid; USD 140,000 - 200,000; Full time

Benefits offered by this job

Wellness stipend

Flexible schedule

Recharge days

Job summary

Phinomenon is building Phi Browser’s AI system. As an AI Engineer you’ll design and ship the core AI loops, integrate frontier models, and ensure local-first memory and safety. You’ll work on browser-native agent capabilities, memory systems, and APIs, shipping weekly into a product people live in.

You’ll collaborate across engineering to balance model choice, on-device constraints, and user data protections, shaping a next-gen browser experience.

Qualifications

• Show us AI systems you've built: agents, RAG/retrieval pipelines, or LLM-powered products in real use.
• Proficiency in TypeScript or Python across agent logic, storage, retrieval, and UI.
• Experience with modern agent patterns: function calling, planning loops, memory, evaluation harnesses.
• Respect for user data and a security-aware design.

Responsibilities

• Build phi-agent's core loops: planning, tool use, skill execution, and recovery when the web fights back.
• Develop browser-native agent capabilities: tab/workspace control, page understanding, record-to-skill workflows.
• Design and build memory/knowledge systems: local-first storage, ingestion to Markdown, hybrid retrieval.
• Ship full stack: APIs, data layers, and web UIs, end-to-end ownership of features.
• Integrate and evaluate frontier LLMs; manage context engineering, cost/latency/quality trade-offs, BYO-LLM.
• Harden AI surface against prompts, adversarial pages, content poisoning; implement safety as a feature.

Skills

TS/Python

Agent patterns

Memory/storage design

Security mindset

Frontend/Backend integration

Release mindset

Tools

Chromium/CDP

Playwright

SQLite/FTS

Embedded vector stores

Job description

Phinomenon is building Phi Browser’s AI system. As an AI Engineer you’ll design and ship the core AI loops, integrate frontier models, and ensure local-first memory and safety. You’ll work on browser-native agent capabilities, memory systems, and APIs, shipping weekly into a product people live in.

You’ll collaborate across engineering to balance model choice, on-device constraints, and user data protections, shaping a next-gen browser experience.