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Cosmin Nicolaescu

Cosmin Nicolaescu

Engineer, operator, and entrepreneur building an AI-native professional services company

cosmin-nicolaescu
Los Angeles, California
San Francisco, California
Joined April 2025
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Summary

Cosmin is a seasoned engineering leader and operator with a proven track record of scaling high-growth technology companies. He was instrumental in scaling Brex from 40 to over 1,000 employees as CTO and previously built core global payments infrastructure and launched Stripe Terminal as an early engineer and manager at Stripe. His career began at Microsoft, working on early versions of Azure and Office365, showcasing a deep technical foundation. cosn+3
He is currently embarking on a new entrepreneurial journey, founding Accrual, a stealth-mode venture focused on modernizing professional services using AI. This move highlights his continuous drive for innovation and his ability to identify and build solutions in new technological frontiers. He has also shared his insights into the challenges and motivations of being a founder in his blog post "Founding fears." cosn+3
Cosmin is an active angel investor and mentor, supporting early-stage founders and executives. He collaborates with venture capitalists to assist portfolio companies and has made numerous angel investments. He also coaches and advises other leaders, demonstrating a commitment to fostering talent and contributing to the startup ecosystem. drexelmagazine+1
His career trajectory reflects a 'pragmatic optimism' and a belief in the compounding effect of investing in growth, valuing time as the most precious resource, and the importance of speed in execution. He believes in smaller, more focused teams and a balanced approach to problem-solving, avoiding extreme positions. He also emphasizes the underrated importance of Emotional Intelligence (EQ) in achieving success, particularly in tech. cosn+1
Cosmin maintains a personal blog where he shares long-form thoughts on building, leadership, and technological trends, including his perspectives on test-driven development and executive transitions. This demonstrates his analytical thinking and willingness to openly share his experiences and insights with the wider tech community. cosn+2

Work

Education

Projects

Writing

Founding fears

August 1, 2024

A reflective piece discussing the anxieties and motivations behind starting a new venture.

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The end of test-driven development

August 1, 2024

An opinion piece on the declining popularity of Test-Driven Development (TDD) and the impact of AI on coding productivity.

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Executive transitions

June 1, 2024

Shares insights and practical guidance on the process of senior-level career transitions, reflecting on his own experience transitioning from Brex CTO.

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A week of stripes

July 1, 2014

A blog post recounting his thrilling first week at Stripe in July 2014, detailing the company culture and work environment.

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Notes

MMMatthew McGrigorsaid they've seen
CNCosmin Nicolaescu
make a big impact as a product or engineering leader at a top FinTech company like Stripe, Adyen, Checkout.com, Brex, or Ramp.

Aug 7, 2025

MSMeg Schedingsaid
CNCosmin Nicolaescu
is one of the most skilled and thoughtful product engineers they've worked with.

Jul 24, 2025