Research / Constructs / Front matter
YAML front matter in five publishing editors
One Markdown fixture, five real publishing editors, tested 2026-08-24. For front matter the observed result was a manual step in WordPress, Substack, Beehiiv, X, and LinkedIn. Every row below is a rule with its own page and its own dated record.
Matches front_matter. Fixture markdown-portability-test-v1. Tested 2026-08-24. How these tests are run.
What happens, per destination
| Destination | What happens | Result | Severity | Rule | Confidence | Last tested |
|---|---|---|---|---|---|---|
| WordPress | Front matter is removed from the body. | Manual step | Action | WP-FM-01 | Verified | 2026-08-24 |
| Substack | Front matter is removed from the body. | Manual step | Action | SUB-FM-01 | Verified | 2026-08-24 |
| Beehiiv | Front matter is removed from the body. | Manual step | Action | BEE-FM-01 | Verified | 2026-08-24 |
| X | Front matter is removed from the post. | Manual step | Action | X-FM-01 | Verified | 2026-08-24 |
| Front matter is removed from the post. | Manual step | Action | LI-FM-01 | Verified | 2026-08-24 |
Manual steps this creates
- WordPress: Copy title, excerpt, slug, tags, and categories into the post fields yourself. (Pasted front matter became separators and a stray paragraph in the tested editor.)
- Substack: Set the post title and subtitle in Substack directly. (A generic renderer turned front matter into a stray heading and divider in the tested paste.)
- Beehiiv: Set the title and any other metadata in Beehiiv directly. (Pasted front-matter fields stayed as visible paragraphs in the tested editor.)
- X: Decide whether the title belongs in the opening line, and carry any other field you still need into the text yourself. (A post has no title, slug, or tag field, so front-matter metadata has nowhere to go, and left in place it would publish as literal text.)
- LinkedIn: Decide whether the title belongs in the opening line, and carry any other field you still need into the text yourself. (A feed post has no title, slug, or tag field, so front-matter metadata has nowhere to go, and left in place it would publish as literal text.)
Limits of what was tested
- Each result describes the surface named beside it, on the date named beside it, and nothing wider.
- A result marked unknown means no dated test covers it. It is not a prediction.
- Rendering is not the same across platform versions, themes, plugins, or email clients.
Prepare a draft
- Check your own draft against all five destinations
- Markdown to WordPress, handoff mode: gutenberg paste
- Markdown to Substack, handoff mode: rich html clipboard
- Markdown to Beehiiv, handoff mode: clean markdown paste
- Markdown to X, handoff mode: plain text
- Markdown to LinkedIn, handoff mode: plain text
Related
- The 5 rules behind this page:
BEE-FM-01,LI-FM-01,SUB-FM-01,WP-FM-01,X-FM-01 - Every construct, side by side
- The full five-destination matrix