Mark Milastsivy

Founder & CEO Firstbase

Last Reviewed: September 19, 2026

Executive Summary

Mark Milastsivy is the founder and Chief Executive Officer of Firstbase.io, a New York-based platform that lets an entrepreneur anywhere in the world start and then actually run a United States company. The problem Firstbase attacks is not incorporation itself, which is a one-day transaction, but everything that follows it: registered agent service, state compliance filings, payroll tax registration, bookkeeping and federal tax filing, each of which is individually mundane and collectively enough to defeat a founder operating from another country and another legal tradition. Milastsivy describes the ambition as an “all-in-one company OS” — one place to launch, manage and grow a business online. Firstbase is unusual among its competitors in that it owns and operates its own registered-agent entities across all fifty states rather than reselling someone else’s network, which is a deliberately capital-intensive choice in a category where most players are brokers.

Career Highlights

• Founded Firstbase.io in 2019 and has led it as Chief Executive Officer since, growing the company to roughly 50 employees headquartered in New York.
• Took Firstbase.io through Y Combinator’s Winter 2021 batch.
• Announced a $3 million seed round in July 2021 backed by Y Combinator, Uncommon Capital, Carta Ventures, Graphene Ventures, Amino Capital and Oyster Ventures.
• Attracted an angel list drawn from the cross-border fintech and digital-residency world, including Taavet Hinrikus of TransferWise, Henry Ward of Carta and Sten Tamkivi of Estonia’s e-Residency programme.
• Built Firstbase into a licensed commercial registered agent operating its own entities in all fifty states, rather than depending on a third-party agent network.
• Reached more than 6,000 companies incorporated for founders in roughly 170 countries by mid-2021, with Brex, Carta and AWS among the platform’s partners.
• Bootstrapped the company to that scale before raising outside capital, running on minimal funding until the seed round.

Professional Journey

Milastsivy’s own account of his pre-Firstbase career is thin by design: he describes himself as a tech entrepreneur and product strategist who launched ventures from a young age and spent that time navigating cross-border business problems and building growth on very little money. No company from that period is named on his own team page or in any interview located, and none is asserted here.

He founded Firstbase in 2019 out of direct experience of the problem. A founder outside the United States who wants access to American customers, American banking and the American investor base has to incorporate there, and the path to doing so runs through registered agents, state filing deadlines, an employer identification number and an annual franchise tax process that assumes local knowledge the founder does not have. Firstbase packaged that path into a product.

The company was bootstrapped through its early growth, raising very little before it had thousands of customers. It entered Y Combinator’s Winter 2021 batch and announced a $3 million seed round in July 2021. The investor roster is the most legible signal of what Firstbase is: TransferWise’s Taavet Hinrikus, Carta’s Henry Ward and Estonia’s e-Residency architect Sten Tamkivi are all people whose own work is about detaching financial and corporate infrastructure from geography.

Since the seed round, Milastsivy has pushed the company past formation into ongoing operations — compliance monitoring, bookkeeping and tax. The strategic decision underlying that expansion was to become a licensed commercial registered agent in its own right across all fifty states, owning the entities rather than brokering access to someone else’s. That gives Firstbase direct control over the compliance layer it sells, which is the part of the product that generates recurring revenue rather than a one-time formation fee. He publishes regularly on corporate compliance and international company formation through contributor platforms including HackerNoon, Entrepreneur and the Forbes Business Council.

Education

No education record for Mark Milastsivy was found in any public source, including Firstbase’s own team page and the company’s Y Combinator listing. It is left unstated here rather than inferred.