What does the Markdown and MDX Formatter do?
Use this tool when you need a browser utility that formats Markdown or MDX with stable wrapping and whitespace using Prettier. It accepts Markdown or MDX source text and returns formatted Markdown or MDX. Results are deterministic for the same input except where cryptographic randomness, current time, or a live provider response is part of the task.
Format source; preview content separately
Use the formatter to normalize repository source and the Safe Markdown Preview to inspect rendered CommonMark-style content. Validate MDX in its actual application build.
How do you use it?
- Choose Markdown or MDX and paste the document.
- Select preserve, always, or never for prose wrapping.
- Format, review the source diff if needed, then copy or download it.
Worked example
Normalize a compact Markdown list
Input
# Notes
* one
* twoOutput
# Notes
- one
- twoThe formatter normalizes spacing and list markers without rendering the document.
Common errors and fixes
| Symptom | Likely cause | Fix |
|---|---|---|
| MDX fails while Markdown succeeds. | The input contains JSX or expressions requiring the MDX parser. | Select MDX and ensure embedded JSX and braces are balanced. |
| Paragraph lines wrap differently. | The prose-wrap option and print width control reflow. | Use preserve when existing manual wrapping must remain. |
Important behavior of Markdown Formatter
MDX runtime semantics depend on the consuming framework and plugin versions, which this formatter does not execute or validate.
Standards and implementation references
- Prettier Markdown documentation (opens in a new tab)Explains Prettier formatting support for Markdown.
- MDX specification (opens in a new tab)Explains how JSX and expressions extend Markdown.
Frequently asked questions about Markdown Formatter
Does the Markdown Formatter upload my input?
No. Processing runs in the current browser tab, and the page does not send tool input to a KitLumi processing endpoint.
What input does the Markdown Formatter accept?
It accepts Markdown or MDX source text. The workspace checks the input and reports malformed or unsupported values before it produces a result.
What does the Markdown Formatter produce?
It produces formatted Markdown or MDX. Copy and download controls appear when the output format supports them.
What limitation should I know?
MDX runtime semantics depend on the consuming framework and plugin versions, which this formatter does not execute or validate.
What changed?
Added Markdown formatting, MDX formatting, Configurable prose wrapping, Local text download, responsive controls, explicit runtime disclosure, and task-specific examples and limitations.