Substack is a hosting platform for newsletters, video and podcasts, with paid subscriptions built in. A newsletter is a series of posts that subscribers receive by email as they are published. A writer starts a publication on Substack, and readers subscribe to it on the web or in the Substack app.
Posts are written in a built-in editor, a CMS (content management system) for formatting posts, embedding media, scheduling and keeping the archive. Each post can be free or only for paid subscribers. Substack handles payments, distribution and subscriber management, and adds podcasts, live video, subscriber chats and comment threads. Readers discover new publications inside Substack's own network, through recommendations, Notes, trending topics and collaborations. The writer keeps ownership of the content, the mailing list and the subscriber payments.
Starting and leaving Substack is free, with no platform fees, tiers or contracts. When a publication charges for subscriptions, the writer keeps 90% of the revenue minus credit card fees, and Substack keeps the rest.