Markdown Preview is designed for technical content where prose and diagrams live together. It helps writers check headings, lists, code blocks, and Mermaid diagrams before publishing to a repository or documentation site.

The preview supports GitHub-flavored Markdown and renders Mermaid fences as SVG, making it practical for README files, architecture decision records, and product specifications.

Use the copy and export actions when you need to move rendered content into another writing or review workflow.

Demo: review Markdown docs with Mermaid blocks

A Markdown preview becomes more useful when diagrams render beside headings, lists, and release notes. This catches broken fences before the document is pushed to GitHub, GitLab, or an internal wiki.

Use fenced code blocks with a language tag such as mermaid.
Keep diagram source close to the paragraph that explains it.
Preview tables and code fences together because one broken fence can corrupt the rest of the page.

# Checkout Flow

```mermaid
sequenceDiagram
  Browser->>API: POST /checkout
  API->>Payment: authorize
  Payment-->>API: approved
```

Publishing checklist: avoid Markdown preview surprises

Markdown engines differ. A browser preview should help you catch structural problems, but final rendering still depends on the platform where the document will live.

Check heading order and avoid jumping from h1 to h4.
Verify code fences close before the next section starts.
Confirm that image URLs and Mermaid syntax are accepted by the target platform.

## Incident Summary

- Impact: checkout latency
- Fix: cache inventory lookup
- Follow-up: add p95 alert

Review checklist for Markdown Preview

Use Markdown Preview when you need to inspect source content visually before it becomes documentation, a pull request note, an incident write-up, or a handoff artifact. Preview Markdown with Mermaid code block rendering.

Before exporting, check that labels are readable, relationships match the source, generated examples do not contain private data, and the preview still makes sense after you edit the input.

Limits and troubleshooting

If the preview fails, reduce the input to the smallest complete example, confirm the format syntax, and then add sections back one at a time. Many rendering failures come from partial files, indentation mistakes, missing diagram headers, or copied snippets that depend on hidden context.

Treat the preview as a review surface rather than a source of truth. Generated diagrams, converted files, dashboards, and rule examples should be checked before they are used in production documentation or operations.

Example inputs to test

Docs: # API Notes Use this document to describe a workflow. - Fast preview - Diagram support - Export actions ```ts const ready = true; ```
Mermaid block: # Checkout flow ```mermaid sequenceDiagram participant Buyer participant Store Buyer->>Store: Place order Store-->>Buyer: Confirmation ``` The diagram is rendered inside the Markdo...
Release notes: # Release notes ## Added - Mermaid preview - PlantUML preview - Markdown preview ## Fixed - Cleaner export toolbar

Tool maturity

Stable renderer

Stable tool

This tool has a dedicated renderer or preview surface, useful exports, and a repeatable browser-first workflow.

The maturity label is not a quality score. It tells visitors whether the tool is best for stable export, deeper debugging, quick parsing, or AI-assisted generation.