Bailey Pumfleet
Bailey Pumfleet is a British developer and entrepreneur who co-founded Cal.comCal.comCal.com is a scheduling software company founded in 2021 by Peer Richelsen and Bailey Pumfleet as Calendso, an open-source alternative to Calendly, and renamed Cal.com later that year. It raised a $7.4 million seed round led by OSS Capital in 2022, and its backers also include Seven Seven Six; in April 2026 it announced it was moving from open source to closed source, citing AI-driven security risks, while keeping an open version as Cal.diy.Open the full entry and is its chief executive. He joined Peer RichelsenPeer RichelsenPeer Richelsen is a German-born entrepreneur who co-founded the scheduling company Cal.com (originally Calendso) with Bailey Pumfleet in 2021 and leads its product and engineering. He previously founded Mage Market, a Magic: The Gathering card marketplace that was accepted into Y Combinator in 2019 and shut down during the pandemic in 2020.Open the full entry within weeks of the first Calendso commit and built much of the early product; in April 2026 he announced that Cal.com was moving from open source to closed source.
Contents5 sections
Key facts
2021Joining Calendso
Cal.com describes Pumfleet as a British developer who joined Peer Richelsen within weeks of the first Calendso commit and built much of the early product. In an interview recorded in May 2022 he said he wrote the first line of code in February 2021 and that the company launched its brand on September 15, 2021; he and his co-founder each drew a $70,000 salary, with all pay disclosed publicly under an open startup model.[1][2]
Role: Chief Executive
As chief executive he leads Cal.com’s go-to-market, marketing, sales and everything else, and is on X as @baileypumfleet.[1]
April 2026Announcing the Move to Closed Source
On April 14, 2026, he announced that after five years as an open-source company Cal.com was going closed source, calling it a difficult decision made for one reason, security: AI can be pointed at an open-source codebase to scan it systematically for vulnerabilities, and protecting customer data had to come first; Cal.diy would remain open for hobbyists.[3]
Related Organizations, Websites, and Public Accounts
Cal.com: Official website: https://cal.com/ (opens in a new window).[1]
LinkedInLinkedInLinkedIn is a social networking platform for professionals. It was founded in 2002 by Reid Hoffman and others, launched in 2003, and listed on the New York Stock Exchange in 2011; after Microsoft acquired it for approximately $26.2 billion in 2016, it became a wholly owned Microsoft subsidiary. Its revenue comes from membership subscriptions, advertising, and recruitment solutions.Open the full entry: https://www.linkedin.com/in/baileypumfleet/ (opens in a new window).[1]