Berk Ozer is a YC S21 founder, angel investor, and product builder based in San Francisco. He co-founded SenpAI, worked on early-stage investing at Orange DAO, and is currently building in AI.

What does Berk Ozer invest in?

Berk Ozer writes angel checks into pre-seed and seed-stage companies, looking for earned secrets from talking to customers and living inside the problem.

Orange DAO is a venture collective of Y Combinator alumni. Berk Ozer served as Venture Lead, investing in 150 startups and helping source and support early-stage companies.

How can I contact Berk Ozer?

You can reach Berk Ozer via DM on X (@berkbuilds) or email at berkozer@gmail.com.

What did Berk Ozer build?

Berk Ozer built SenpAI, an AI-powered gaming coach that was essentially "ChatGPT for gamers" in 2019, three years before the mainstream LLM wave. He also built Brunner (AI orchestration for running loops), MindSpace (RAG personal knowledge base), and Muxio (unified MCP gateway for AI agents).

Berk Ozer

Building Reactorfield. Prev: SenpAI (YC S21) and Orange DAO.

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About

Builder first, investor second.

I'm Berk Ozer. I've spent most of my career building products, and some of it backing people who build them. Previously I co-founded SenpAI (YC S21), a real-time AI gaming coach. We shipped "ChatGPT for gamers" in 2019, three years before the LLM wave hit the mainstream, and scaled it to 500K monthly active users with near-zero ad spend. At Orange DAO, I invested in 150 startups and worked closely with founders on product, distribution, and fundraising. The portfolio went on to raise $100M+ in follow-on funding. Based in SF. Currently building something new.

How I Help

A few places I help founders.

Fundraising

I’ve raised millions from VCs as a founder and invested in hundreds of startups. I help founders tighten what actually gets meetings and term sheets: narrative, blurb, investor memo, warm intros, objections, and the fundraising sprint.

Distribution

I’ve built consumer growth loops and investor networks from zero. I help founders move from launches into repeatable motion: who to reach first, what channel to bet on, what message gets a response, and what loop keeps working after the first spike.

Product

I’ve built AI products from prototype to millions of users, and learned the hard way that usage is not the same as urgency. I help founders sharpen the wedge, find the real customer, and cut what makes the product harder to understand.

Angel Investments

I write angel checks into pre-seed and seed-stage companies.

I look for earned secrets from talking to customers and living inside the problem. I back resourceful founders with non-obvious ideas before everyone else agrees.

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Writing

Notes on fundraising, AI, and building.

AI-Native Founder Skill Allocation Becomes a Barbell

Founder work is becoming more human at the edge, more autonomous at the core, and compressed everywhere in the middle.

May 21, 2026

Fundraising Mistakes I Only Realized After Switching to the VC Side - Part II

The mistakes you make while looking the investor in the eye. The ones that feel like good instincts. They're not. I only saw them clearly after becoming a VC.

Feb 17, 2026

Fundraising Mistakes I Only Realized After Switching to the VC Side

I raised $3M+ as a YC founder. Then I switched sides, reviewed 8,000+ startup applications, and watched hundreds of founders make the same mistakes I did.

Feb 10, 2026

All writings

Experience

Where I’ve been.

Reactorfield

Founder

2026 - Present

->Helping scientists & deep tech teams use AI the way frontier labs do.

Superpath

Founder

2025 - Present

->Work hands-on with early-stage founders on fundraising, distribution, and product. If you're interested, say hi.

Orange DAO

Head of Venture & Product

2023 - 2025

->Led 40+ reviewers to evaluate 8,000+ startup applications - invested in 150+ startups
->Built GTM playbook defining acquisition channels and founder personas - drove 5,000+ startup applications annually
->Served as Group Partner for 12-week accelerator, coaching 100+ teams on PMF and fundraising - portfolio raised $100M+ follow-on
->Organized Demo Days for 7 batches - coordinated 500+ investor attendees including a16z, Paradigm, and Coinbase Ventures
->Managed Launchcaster (acquired) serving 15,000+ builders - shipped LLM-powered Orange Portal with onchain data integration

SenpAI (YC S21)

Co-Founder & Head of Product

2019 - 2024

->Built real-time AI gaming coach pre-GPT era - shipped "ChatGPT for gamers" three years before ChatGPT existed
->Scaled from hackathon prototype to 500K+ MAUs and 4M+ games analyzed monthly
->Launched SEO and content campaigns generating 1.5M+ monthly organic visits - reduced CAC by 10x
->Raised $3.1M seed from Y Combinator, VCs, and angels - crafted investor narratives rooted in metrics and cohort analysis

FashionI

Co-Founder & Head of Product

2017 - 2019

->Built and scaled AI fashion assistant to 20,000+ WAUs
->Featured by Apple as "Try Something New" - one of few apps highlighted for design innovation

Deloitte Digital

Management Consultant

2016 - 2017

->Led C-Suite design thinking workshops on AI, IoT, and Blockchain - launched net-new IoT consulting offering for the firm
->Guided Fortune 500 client through $10M+ digital transformation - bridged technical strategy with business stakeholders

Communications & Spectrum Management Research Center

Software Developer

2011 - 2014

->Developed AI algorithms for national energy grid operations - multi-million dollar impact, published in peer-reviewed journals