Convert your Markdown articles to Substack-ready HTML for newsletters. Clean paste, paywall markers, embed-friendly links — free for writers worldwide, no sign-up.
Open Editor for Substack →%%paywall%% or <!--paywall-->Choosing a home for your newsletter or long-form writing? Read our free guides:
These rules target Substack the newsletter product — web reader and email client, not just an editor.
| Rule | What Formatio does | Why it matters on Substack |
|---|---|---|
| Title | Strips the leading H1 | Substack keeps the title in a separate field above the body |
| Paywall | Normalizes %%paywall%% and [paywall] markers to the paywall comment | Substack recognizes its paywall marker and splits free and paid content there |
| Embeds | Hints for YouTube, X/Twitter, Spotify and SoundCloud URLs | Substack auto-embeds bare URLs on their own line |
| Links | Flags relative URLs | Newsletter emails are more reliable with absolute URLs |
| Code | Cleans code blocks to simple markup | Substack renders lightweight code blocks in posts and emails |
Comparing newsletter platforms? See Medium vs Substack and Substack vs LinkedIn.
Formatio converts your content into clean HTML that Substack’s editor accepts. Copy as rich text, paste into a Substack post, and put the title in Substack’s title field. Keep embed URLs on their own line for auto-embeds.
Yes. Add a paywall marker such as %%paywall%% or <!--paywall--> in your content. Formatio normalizes it for Substack so paid-only content can sit below the marker.
Yes. Formatio is free, runs in your browser, and works for global audiences. Optional AI features use a secure proxy only when you choose them.
Add a line with the paywall marker in Formatio. It is normalized to Substack's paywall comment, and the preview shows exactly where the free portion ends.
Rich embeds like YouTube and Spotify are auto-embedded on the web version; in emails Substack falls back to a link card. Formatio keeps the URLs on their own lines so both paths work.