Markdown Preview with outline and publishing checks
Preview GitHub-flavored Markdown locally, inspect headings, tables, links, task lists, and code blocks, then copy the draft into README files, docs, issue comments, or support articles.
Rendered locally with GitHub-flavored Markdown support. Raw HTML is not executed by this preview.
Rendered preview
Markdown preview is a publishing rehearsal, not a guarantee that every platform renders exactly the same.
Release checklist
Use this draft to review a Markdown document before publishing.
Summary
**FreeToolsBox** focuses on local-first developer utilities with clear examples and safety notes.
Tasks
• [x] Check headings
• [x] Preview tables
• [ ] Confirm links
Example table
| Area | Status | Note || --- | --- | --- || JSON | Ready | Tree preview added || Markdown | Review | Outline and health checks |Code snippet
const safe = "Use sanitized examples";Avoid pasting private drafts, customer records, or unreleased roadmap details into shared devices.
Markdown health checks
Publishing readiness signals
A single H1 helps readers understand the page purpose.
H2 sections make longer docs easier to scan.
Check destination URLs before publishing or sharing.
Use fenced code blocks for snippets that should not be reformatted.
GFM tables are useful, but some editors may render them differently.
Task items are convenient in GitHub issues and project docs.
Common Markdown mistakes (and how to fix them)
These formatting errors can break rendering on GitHub and documentation platforms.
<div style="color: red">Important note</div>
Why it is a problem
GitHub, many CMS platforms, and static site generators sanitize or strip raw HTML in Markdown for security. The preview here may show HTML that your target platform silently removes.
How to fix
Prefer Markdown syntax over raw HTML when possible. Use blockquotes (>), bold (**), and tables instead of inline styles. If HTML is essential, test rendering on the target platform before publishing.
Paragraph text - List item 1 - List item 2
Why it is a problem
Without a blank line between a paragraph and the following list, many Markdown renderers treat the list as a continuation of the paragraph rather than a separate block. The same applies to code blocks and blockquotes.
How to fix
Always add a blank line before and after lists, code blocks, tables, and blockquotes. This ensures consistent rendering across GitHub, GitLab, documentation generators, and CMS platforms.
| Column 1 | Column 2 | | Cell 1 | Cell 2
Why it is a problem
Tables require a header separator row with dashes: |---|---|. Without it, the table renders as plain text. Inconsistent column counts across rows also break table rendering.
How to fix
Always include the separator row: | Column 1 | Column 2 | |---|---| | Cell 1 | Cell 2 |. Ensure every row has the same number of pipe-delimited columns. The health checks panel flags common table issues.
[Click here](https://example.com/old-page-that-no-longer-exists)
Why it is a problem
Broken links in documentation undermine reader trust and harm SEO. Links that work in preview may point to internal staging URLs, expired paths, or pages that require authentication.
How to fix
Click every link in the preview to verify it resolves correctly. Use relative paths for internal documentation links (./other-page.md) rather than absolute URLs that may break when the domain changes.
Real-world use cases
Previewing README changes
Draft a README update and preview the rendered output before pushing to GitHub. Check heading hierarchy, code block formatting, link text, and table alignment — all in one view.
Drafting GitHub issues and pull requests
Write an issue description or PR summary with task lists, code snippets, and links. The preview shows exactly how it will look after submission, reducing edits after posting.
Writing documentation drafts
Compose documentation pages for a static site, wiki, or knowledge base. The outline view helps verify heading structure; health checks catch broken tables and missing sections.
Checking table alignment
Paste a Markdown table to see how it renders. The health checks panel warns about inconsistent column counts — a silent error that makes tables unreadable on platforms like GitHub.
Creating task lists for team coordination
Use GitHub-flavored task lists (- [ ] and - [x]) to create checklists in issues, PRs, and project documentation. The preview confirms checkboxes render correctly.
Frequently asked questions
What flavor of Markdown does this preview support?
This preview renders GitHub-flavored Markdown (GFM): tables, task lists (- [ ]), strikethrough (~~), autolinks, and fenced code blocks with language hints. It does not support platform-specific extensions like Mermaid diagrams, math formulas (LaTeX), or custom shortcodes.
Is raw HTML rendered in the preview?
No. Raw HTML is displayed as text, not executed. This is a security boundary: executing arbitrary HTML in a preview would risk XSS. If you need HTML rendering, test on your target platform directly.
Can I upload or embed images?
No. This is a text-only Markdown preview. Image Markdown syntax () is recognized in the outline, but images are not fetched or rendered. Use your target platform to verify image embedding.
Is my document saved or stored?
No. Markdown input is processed entirely in your browser and is never transmitted or persisted by this tool. When you close the tab, your draft is gone. For long-form writing, compose in a local editor and paste here for final preview.
Why does my table look broken in the preview?
Common causes: missing separator row (the |---|---| line), inconsistent column counts across rows, or missing leading/trailing pipe characters. The health checks panel flags specific table issues. Also check for blank lines between the table and adjacent content.
Related tools you might need
Compare two versions of Markdown before and after edits to review every change.
Format CSS embedded in Markdown documentation and code blocks.
Format JSON code blocks copied from API documentation into readable shape.
Count words, characters, and estimate reading time for longer documentation drafts.
Tool guide
About Markdown Preview
Markdown preview lets you write plain-text Markdown and see the rendered result in real time. It is useful for README files, documentation, notes, changelogs, blog drafts, support articles, and GitHub-style content.
The live preview helps catch broken headings, lists, links, tables, code blocks, and formatting before you publish or paste the content elsewhere. GitHub-flavored Markdown support is helpful for technical documentation workflows.
Markdown rendering can vary between platforms. Always check the final output in the target system when exact formatting matters.
Privacy note
Most FreeToolsBox tools run directly in your browser for processing. Some pages may still load analytics, ads, or third-party services. Avoid entering passwords, private keys, production tokens, personal IDs, or other sensitive data.
Validation-grade guide
How to use Markdown Preview well
Best for
Preview GitHub-flavored Markdown drafts with tables, lists, code blocks, links, and document outline checks.
Lets writers and developers inspect Markdown structure before pasting docs into GitHub, README files, CMS fields, issue comments, or support knowledge bases.
Example workflow
- Input: Paste a README section, release note, documentation draft, or issue template.
- Action: Preview rendering, inspect the outline and checks, then copy the cleaned Markdown for publishing.
- Expected result: Formatting mistakes, missing headings, broken structure, and risky raw HTML assumptions are easier to catch before publishing.
Quality checks
- Renders GitHub-flavored Markdown and keeps raw HTML disabled by default.
- Shows outline, word count, code block, table, and link checks beside the preview.
- Includes practical guidance for safer sharing and documentation review.
Watch out for
- Markdown rendering differs between GitHub, Slack, CMS editors, and documentation generators.
- Raw HTML may be ignored or sanitized depending on the target platform.
- Very large documents can be slow to render on low-end devices.
Do not use it for
- Publishing private drafts, customer data, unreleased roadmap details, or regulated information from a shared browser.
- Assuming the preview exactly matches every downstream Markdown renderer.
What to measure in the 90-day validation
- tool_used:load-example
- tool_used:clear
- tool_copied
- outline inspected
Markdown preview renders locally in the browser; raw HTML is not executed by this preview component.
Learn the concept
Safe Markdown preview workflow
A practical guide to previewing Markdown structure, links, tables, code blocks, and task lists before publishing documentation or support content.
Read the guide →Common use cases
- Preview a README before committing it to a repository.
- Draft documentation with headings, lists, links, and code blocks.
- Check Markdown tables and task lists before publishing.
- Write release notes, changelogs, or support articles in a lightweight editor.
- Clean up copied Markdown before pasting it into GitHub, GitLab, or a CMS.
Examples
- Write a README section with headings, bullet lists, and code fences, then verify the preview.
- Paste a Markdown table and check whether columns render correctly.
- Draft release notes with links and task lists before copying them into a repository.
Practical tips
- Use fenced code blocks with language names for clearer technical docs.
- Preview tables on smaller screens because wide Markdown tables can overflow.
- Different platforms may handle line breaks and HTML tags differently.
- Keep Markdown source readable; future edits are easier when formatting is consistent.
Related tools
Frequently asked questions
What is Markdown preview?
Markdown preview renders plain-text Markdown into formatted HTML so you can see how headings, lists, links, code blocks, and tables will look.
Does it support GitHub-flavored Markdown?
The tool is designed for common GitHub-style Markdown workflows, including technical documentation patterns.
Why does my Markdown look different elsewhere?
Markdown processors vary. GitHub, CMS platforms, chat tools, and documentation systems may support different extensions or styling.
Can I use it for README files?
Yes. It is especially useful for checking README structure before committing or publishing.
Is Markdown the same as HTML?
No. Markdown is a lightweight writing syntax that is usually converted into HTML for display.
Is Markdown Preview free to use?
Yes. Markdown Preview is free to use in your browser with no signup required.