Research / Constructs / Raw HTML
Raw HTML inside Markdown in five publishing editors
One Markdown fixture, five real publishing editors, tested 2026-08-24. For raw html the observed result was untested in LinkedIn; a manual step in X; degraded in WordPress, Substack, and Beehiiv. Every row below is a rule with its own page and its own dated record.
Matches html_raw. 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 |
|---|---|---|---|---|---|---|
| Math, Mermaid, Obsidian syntax, raw HTML, and heading anchors are not live-verified on LinkedIn. | Unknown | Evidence gap | LI-SPECIAL-01 | Unknown | 2026-08-24 | |
| X | Math, Mermaid, Obsidian syntax, and raw HTML are resolved to readable text or a media task. | Manual step | Action | X-SPECIAL-01 | Verified | 2026-08-24 |
| WordPress | Raw HTML is removed; its visible text is kept. | Degraded | Review | WP-HTML-01 | Verified | 2026-08-24 |
| Substack | Raw HTML is removed; its visible text is kept. | Degraded | Review | SUB-HTML-01 | Verified | 2026-08-24 |
| Beehiiv | Raw HTML is removed; its visible text is kept. | Degraded | Review | BEE-HTML-01 | Verified | 2026-08-24 |
Manual steps this creates
- LinkedIn: Check this part of the output yourself before posting. (The focused standard-post test did not isolate these constructs, so no reliable claim exists yet.)
- X: Check each one reads correctly, or attach it as an image. (The composer has no control for any of these and the focused test did not isolate each one.)
- WordPress: Rebuild with a reviewed Details or Custom HTML block if you need the behavior. (Gutenberg flattened the details structure and the Markdown Block escaped raw HTML.)
- Beehiiv: Use the native HTML snippet control if you need the markup. (Raw paste showed literal markup in the tested editor.)
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-HTML-01,LI-SPECIAL-01,SUB-HTML-01,WP-HTML-01,X-SPECIAL-01 - Every construct, side by side
- The full five-destination matrix