Substack content guides.

A letter, not a feed post.

The long-form section of our multi-platform guide covers Substack beside Medium and your own website, and separates the three by two questions: who owns the audience, and how a reader finds you. Substack is the list you keep — you can export your subscribers as a file — so it is the one social-style platform where the audience is yours.

A newsletter built from what a business knows shouldn't be a digest of links to its other posts. It should be a letter: one argument told properly, more personally than a feed post allows, with the detail there was no room for anywhere else. This page collects every guide on the blog that covers Substack; today that is one guide, and the section above is the place to start.

Substack for a business, in detail.

What a publication is allowed to be

Substack's content guidelines describe the platform as being for high-quality editorial content, not conventional email marketing. They do not permit publications whose primary purpose is to advertise products or services, drive traffic to other sites or improve search rankings, and they say brands and commercial organisations may be asked for additional verification. So a business newsletter on Substack has to teach. A mention of your own work belongs late in an issue, briefly, where it is genuinely relevant.

Posts, Notes and the inbox

Substack has two formats. A post is the article: it sits in the publication's archive, carries its own SEO title, description and URL, and can be sent to subscribers' inboxes or published to the web only — a choice made post by post. A Note is a short public post on the web and in the app, and it is never emailed. Long-form always goes out as a post; a Note is one idea taken from it.

What can be automated

The preparation, almost entirely; the publishing, no. Substack's developer API reads public profile and publication data only, so it cannot publish a post or read a subscriber list. A system can draft each issue from your knowledge base, set out its title, subtitle, URL and SEO fields, and remind someone when it is due. A person pastes it into Substack's editor, sends a test email to themselves, and publishes or schedules it.

AI, and being honest about it

Since July 2026, Substack has let readers scan a post to estimate how much of it was written by hand or with AI assistance, and let a publication add a “How I make this” statement explaining its process. If AI drafts and a person edits, the statement should say so plainly. Readers who were told already are not surprised by a scan; readers who were not told, are.

How a newsletter grows

Slowly, and mostly through readers: the Substack app, Notes, and recommendations between publications, which Substack shows to new subscribers as they sign up. None of that rewards volume. An emailed issue cannot be resent, and a subscriber who feels flooded unsubscribes for good, so publishing steadily to the web and emailing only the strongest issues is usually the better rhythm.

Substack, built for you.

A newsletter drafted from what a business knows, and published by a person, is one of the systems we build.