Substack is a publishing platform where writers send newsletters and charge readers for subscriptions. It was founded in 2017 in San Francisco by Chris Best, Jairaj Sethi and Hamish McKenzie, and it became the best known home of independent paid newsletters.
What it is
Writers can offer free or paid subscriptions and make selected posts public. Substack usually takes ten percent of subscription payments and earns no revenue from advertising placed by publishers. Over time it added podcasts, discussion threads, the Notes feed in April 2023, a reader app and, in January 2026, a beta app for television.
History
Wikipedia lists a 2018 seed round from The Chernin Group and others, and 15.3 million dollars from Andreessen Horowitz in 2019. In July 2025 it raised 100 million dollars at a valuation of 1.1 billion dollars. Wikipedia reports more than 500,000 paying subscribers in November 2021 and about five million paid subscriptions in March 2025, and in October 2025 the company said 50,000 creators were earning money on the platform.
Debates
The platform has been criticized over its light moderation policy, including coverage in November 2023 of extremist newsletters, and Wikipedia also reports a security breach disclosed in February 2026. The founders have defended minimal censorship.
Why it matters to founders
Substack defined the paid newsletter model and its network features, such as recommendations and Notes, make it both a publishing tool and a discovery channel. See Newsletter growth.
Related entries
See Chris Best, Substack, Beehiiv and Newsletter growth.
Substack is part of Communities and communication.
Sources
Wikipedia entry for Substack. Reviewed October 2026.
