A newsletter and subscription publishing platform where writers publish long-form posts to email and web, charge for subscriptions, and grow through a built-in recommendation network.
Last verified · 2026-07-10 · by Moe Ameen
Substack is a publishing platform for writers, not an AI tool. It was founded in 2017 in San Francisco by Chris Best (its CEO, previously a co-founder of Kik), Hamish McKenzie, and Jairaj Sethi. The core idea is simple: you write a post, and Substack sends it to your subscribers by email and publishes it on your own Substack page at the same time. There is a built-in editor with formatting and scheduling, and you own your subscriber list — you can export it and leave.
The business model is what made Substack distinct. Publishing is free, and Substack makes money by taking a flat 10% cut of any paid-subscription revenue you earn. On top of that, Stripe (which processes the payments) charges roughly 2.9% plus $0.30 per transaction along with a recurring-billing fee, so the real all-in cost of a paid subscription lands closer to 13–16% of gross once processing is included — but there is no monthly platform fee, so you pay nothing until your readers pay you.
Beyond newsletters, Substack has grown into a wider content network. Notes, launched in April 2023, is a short-form Twitter/X-style feed where writers post ideas and readers discover new publications. There is support for podcasts, audio, and video posts; Substack Chat for group conversations; live streaming; comments; and a recommendation network plus in-app discovery that helps existing subscribers find new writers. Native iOS and Android apps give readers a single feed of everything they subscribe to, and creators get analytics on open rates, subscriber growth, and revenue.
The honest framing: Substack is a distribution and monetization home for one channel — your newsletter and its subscriber relationship. It does not generate content for you, and it does not publish to Instagram, TikTok, YouTube, LinkedIn, or the other social platforms where creators also need to show up. It is the place your written work lives and earns, not an engine that makes or fans out that work across the web. Treat the fee structure and feature set as current as of the verification date and confirm specifics on Substack's own pages.
Substack is where a piece of writing lives and earns; it is not built to carry that writing to the platforms where the rest of your audience scrolls. A 1,500-word essay that took you all morning publishes to email and your Substack page — and then it sits there. It does not become a TikTok, a set of Reels, a LinkedIn carousel, a quote graphic, or an X thread. That last-mile fan-out is exactly the job Kompozy is built for, and it is the difference between a post that reaches your existing list and one that pulls new subscribers back to Substack.
Point Kompozy at a published Substack post and it treats the essay as a source, then generates a full week of derivative content from it: Clipped Shorts and Persona Shorts for TikTok, Reels, and Shorts, brand-exact Carousel Posts for Instagram and LinkedIn, Quote Graphics and Infographic Photos pulling the sharpest lines, native Text Posts, and an X thread — all held to one voice by your Persona Brief and banned-word filters so nothing reads like generic AI. Kompozy then schedules and publishes that set across all nine connected social platforms from one queue, with every social post able to drive readers to the Substack subscribe page. It also works the other direction: Kompozy generates Email Newsletter drafts as one of its native formats, so you can draft the issue in Kompozy, keep it on-brand, and paste or pipe it into Substack to send. Substack owns the subscription and the send; Kompozy owns the generation and the cross-platform reach that grows it.
Substack is a publishing platform, founded in 2017, where writers publish newsletters to email and web, charge for subscriptions, and grow through a built-in recommendation network. It also includes Notes (a short-form feed), podcasts, video, chat, and mobile apps. It is a distribution and monetization tool, not an AI content generator.
Publishing is free with no monthly platform fee. When you charge for subscriptions, Substack takes a flat 10% of that revenue, and Stripe adds roughly 2.9% plus $0.30 per transaction along with a recurring-billing fee — so the real all-in cost of paid subscriptions lands closer to 13–16% of gross once processing is included. Confirm current numbers on Substack's pricing page.
No. Substack distributes within its own ecosystem — email, your Substack page, Notes, and the app. It does not generate short-form video or carousels and does not schedule or publish to Instagram, TikTok, YouTube, LinkedIn, or X. A content engine like Kompozy handles turning a Substack post into posts for those platforms.
Bring the published post (or an episode transcript) into Kompozy. Kompozy generates Clipped and Persona Shorts, carousels, quote graphics, native text posts, and an X thread from it — kept on-brand by your Persona Brief — then schedules and publishes them across nine platforms, each pointing back to your Substack subscribe link.
Kompozy generates Email Newsletter drafts as one of its native text formats, governed by your Persona Brief and banned-word filters. You can draft the issue in Kompozy to keep it consistent with the rest of your content, then paste or pipe it into Substack to schedule and send to your subscribers.