J4 Ventures

J4 Ventures is an early-stage technology venture capital firm founded in 2021 and based in New York City. The firm backs exceptional entrepreneurs addressing large markets with technology-driven or tech-enabled businesses, with a particular focus on finance, workplace, climate, and AI sectors. General Partners Bruce Jaffe, Jamie Rapperport, and John Mitchell lead the firm, supported by Venture Partner Brian Jacobs. Rapperport brings more than 25 years of software entrepreneurship experience as co-founder and CEO of Eversight, acquired by Instacart, and as co-founder of Vendavo, a leading B2B pricing platform. Collectively, the team brings three decades of venture experience, 25 years in Big Tech, and involvement in over 500 prior investments across two funds — Fund I and Fund II (2024 vintage). J4 Ventures invests at the pre-seed and seed stages in US-based startups, with check sizes between $500K and $1 million. The portfolio of 15 companies includes Molten Industries (clean graphite and hydrogen, which raised a $25 million Series A), Yoodli (AI speech coaching), Gooey AI, LearnLux (financial wellness), Wordware (LLM deployment), Take2 AI (job simulation platform), Upwage (workforce platform), Ruby Money, Learn to Win, and Atomic Limbs. Exits include Zelta and UpLink. J4 Ventures operates with a stated commitment to humility and integrity, prioritizing deep trust and genuine collaboration with founders. The firm seeks to back founders building scalable businesses across AI, fintech, climate, and the future of work, with a hands-on approach that reflects the team's own decades of operating and investing experience.