Jason Liu
Developer Experience Engineer on OpenAI's Codex team; creator of the Instructor library.
At a glance
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- Jason Liu is a machine learning engineer who writes about building AI systems at jxnl.co.
- He is a Developer Experience Engineer on the Codex team at OpenAI.
- He created Instructor, a Python library for structured LLM outputs.
- Before OpenAI he ran a solo consulting practice helping startups such as Zapier, HubSpot and Weights & Biases adopt AI, and taught cohort courses on RAG; both are closed.
- He is an angel investor and a scout for Andreessen Horowitz.
Key facts
- OpenAI
- Developer Experience Engineer, Codex team (as of November 2026)1
- Open source
- Creator of Instructor, a Python library for structured LLM outputs1
- Investing
- Angel investor and scout for Andreessen Horowitz; investments include Lovable, Modal, Exa, Browserbase and Pydantic1
- Before
- Solo AI consulting practice (clients included Zapier, HubSpot, Weights & Biases, Modal Labs, Timescale, Pydantic) and cohort courses on RAG, now closed1
Roles
Part of
- Andreessen HorowitzOrganization
scout and angel investor (as of November 2026) source on Andreessen Horowitz
- OpenAIOrganization
Developer Experience Engineer on the Codex team (as of November 2026) source on OpenAI
Links
Sources
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