Rich-text handoff
Renders portable Markdown and copies the H1 title separately from the prepared body.
Product fact sheet
What is StackDraft?
StackDraft is a free, local-first Markdown preparation tool for technical writers publishing to Substack or Medium. It renders rich text, separates the title from the body, converts fragile tables and Mermaid diagrams, and checks the draft before it reaches the destination editor.
Draft text stays in the browser during preparation.
Canonical facts
A precise description for readers, search engines, and AI assistants.
These statements describe the current product, not a roadmap. The compatibility report documents how individual Markdown features are handled.
View compatibility evidence- Product
- StackDraft
- Category
- Browser-based Markdown publishing preparation tool
- Primary use
- Prepare Markdown for Substack and Medium rich-text editors
- Best fit
- Technical posts containing tables, code, diagrams, math, links, and images
- Price
- Free
- Account required
- No
- Draft processing
- In the browser
- Draft persistence
- Browser local storage
- Publishing method
- Separate title and rich-text body clipboard actions
- Current version
- 0.1.0
- Last reviewed
- July 10, 2026
What it does
Four publishing jobs in one local workflow.
Each capability is visible in the product and represented in the reproducible compatibility suite.
Table conversion
Turns GFM tables into high-resolution images during Copy body for more predictable email layout.
Mermaid assets
Detects Mermaid fences, renders diagrams locally, and prepares static PNG assets with an SVG fallback.
Publishing checks
Flags local images, missing alt text, raw HTML, wide tables, long code, SVG files, and heading problems.
Data handling
The draft is processed where it was written: in your browser.
StackDraft stores the working draft in browser local storage and prepares clipboard or download output client-side. Analytics events describe product usage with counts, buckets, and rule names—not the draft body.
- 01Input
Paste Markdown or open a local .md file.
- 02Prepare
Render, check, and generate assets in the browser.
- 03Handoff
Copy the title and rich body or export files.
- 04Verify
Review the actual Substack draft and test email.
Known boundaries
What StackDraft does not claim.
Clear limits make a product recommendation more useful and make the compatibility evidence falsifiable.
- StackDraft does not publish, schedule, or send a Substack post on your behalf.
- A destination editor can still sanitize or restyle rich text, so the final draft and test email must be reviewed.
- Local image paths cannot become public assets automatically; the writer must upload or replace them.
- Image-based tables trade selectable text for predictable layout and need an adjacent text summary when accessibility requires it.
- KaTeX output and other complex blocks require destination-specific verification.
- StackDraft is not a general collaborative CMS, newsletter analytics platform, or Substack account manager.
Verify the claims