Substack
San Francisco-based platform founded in 2017 for independent writers and creators to publish newsletters, podcasts and video and charge subscribers. It raised a 100 million dollar Series C in July 2025.
Industry: Subscription publishing platform | Location: San Francisco, United States | Founded: 2017 | Total Funding: USD 100M
About Substack
Substack is a publishing platform that gives writers and other creators tools to publish newsletters, podcasts and video and to charge readers for them. Its website says writing is free to start, creators keep 90 percent of their revenue less card fees, and the platform has about 5 million paid subscriptions. The company is headquartered in San Francisco and says it has more than 150 people, with offices in New York City and London.
Substack was founded in 2017 by Chris Best, Hamish McKenzie and Jairaj Sethi, and was part of Y Combinator's winter 2018 batch. Best, formerly a co-founder of Kik Messenger, is chief executive; Sethi, who led platform engineering at Kik, is chief technology officer; and McKenzie, a former PandoDaily reporter, is chief writing officer.
The product started with email newsletters and added podcasts in 2019. Substack Chat followed in November 2022 and Notes, a short-form feed, in April 2023. Video posting and monetisation reached the app in February 2025, and a Substack TV beta for Apple TV and Google TV followed in January 2026. In April 2024 it partnered with Spotify on podcast distribution.
In May 2021 Substack took on the team of People & Company, a Brooklyn community consulting startup. Wikipedia reports a 2018 seed round from investors including The Chernin Group, Zhen Fund, Emmett Shear and Justin Waldron, and a 2019 Series A in which Andreessen Horowitz put in 15.3 million dollars.
On 17 July 2025 Substack announced a 100 million dollar Series C led by BOND and The Chernin Group, with Andreessen Horowitz, Rich Paul of Klutch Sports Group and Jens Grede of Skims also taking part. BOND's Mood Rowghani was to join the board. TechCrunch, citing The New York Times, put the valuation at 1.1 billion dollars, nearly 70 percent above its 2021 level, and reported more than 5 million paid subscriptions in March 2025. Substack said the money would fund creator tools and international growth.
TechScoop reported in July 2026 that Substack uses the AI-text detector Pangram to let readers filter AI-written posts.
Leadership
- Chris Best, Co-founder and Chief Executive Officer
- Hamish McKenzie, Co-founder and Chief Writing Officer
- Jairaj Sethi, Co-founder and Chief Technology Officer
- Mood Rowghani, Board member; general partner, BOND