YC Summer 2026 (S26) founder

Joanathan McIntosh

Founder of Billow AI Labs, AI-native Accounting Firm that's killing Deloitte

Company

Joanathan McIntosh is listed as a founder of Billow AI Labs. Billow handles the work of Accounting and FP&A FTEs keeping teams compliant and audit-ready. We work within existing stacks (NetSuite, Coupa, and 80+ other systems) and complex spreadsheets, chasing down information and coordinating approvals across stakeholders. Built by repeat founders; Joan built and exited an accounting/ERP platform (45,000 businesses in 4 years) and Phil built Bloomberg's financial “brain” data infrastructure, and as CTO of a trading platform ($1B in volume). Advisors include CFOs, controllers, auditors from publicly-traded biopharma, and a Big-4 Accounting firm.

Founder traction evidence

Public posts and activity attributed directly to this founder.

  1. X

    We did $100k in revenue after realizing that our customers hate software.

    We did $100k in revenue after realizing that our customers hate software. Our first product was an AI accounting tool for CFOs. I did 35 sales calls and got $0. So we switched to being a service. The pitch became: "We're an outsourced accounting firm that's faster/cheaper with

  2. X

    Introducing Billow (YC S26) We're killing Deloitte.

    Introducing Billow (YC S26) We're killing Deloitte. Accounting is a $700B industry, but 80% of companies still do it by hand. Billow is an AI-native accounting firm that replaces humans with agents. We connect to your existing tools (NetSuite, QuickBooks, and 80+ other

  3. X

    I left my home country of Indonesia for the United States when I was 16.

    I left my home country of Indonesia for the United States when I was 16. My parents weren't supportive, so I worked three jobs to survive, from selling chocolate to driving Ubers. Today, I'm a 2x founder (45k customers, raised $2m) and just launched my company on YC

  4. LinkedIn

    The Billow AI (YC S26) is now backed by Y Combinator

    The Billow AI (YC S26) is now backed by Y Combinator. Excited for the next 12 weeks and to build AI employees for finance teams.

  5. X

    Our YC launch hit 350k views and 1.2k likes.

    Our YC launch hit 350k views and 1.2k likes. 42 sales calls booked in 3 days, including a consumer brand doing $400m in revenue. Onwards to Demo Day!

  6. X

    need advice: cofounder is a maga

    need advice: cofounder is a maga

  7. X

    I used to be terrified of public speaking because people laughed at my accent.

    I used to be terrified of public speaking because people laughed at my accent. So I spent my college weekends tabling at a Farmer's Market to practice English. Eventually, I got a job at Merrill Lynch, and now I'm building a startup in @ycombinator I don't think I'll ever

  8. X

    Critics will say that AI-native services aren't scalable because we still need to hire people.

    Critics will say that AI-native services aren't scalable because we still need to hire people. They're right. We still need human accountants to help us serve customers. But this is a temporary solution. Our bet is that over the next 6-12 months, LLMs & AI agents will get