The ToolMint Markdown Previewer lets you write, paste or upload Markdown and see a live rendered preview in the same browser tab. It supports common Markdown plus practical GitHub Flavored Markdown features such as tables, task lists and strikethrough. You can copy the original Markdown, copy the generated HTML, download a .md file or download a standalone HTML file without sending your document to ToolMint servers.
Markdown previewing is useful when you are drafting README files, documentation notes, changelog entries, technical articles, support snippets or content that will later be pasted into a CMS. The goal is simple: keep the source text readable while checking how headings, lists, links, code blocks and tables will render before you publish or share the file.
What a Markdown previewer does
A Markdown previewer converts Markdown syntax into HTML for display. A line that begins with # becomes a heading, text wrapped in ** becomes bold, fenced code blocks become formatted code, and table syntax becomes an HTML table. The source stays editable as plain text, while the preview shows the rendered structure that a reader will see.
ToolMint uses the existing Markdown parser in the project and runs it locally in the browser. The preview updates as you type, paste or load a file. The generated HTML is sanitized before it is displayed, copied or downloaded, so the tool is designed for previewing content rather than executing embedded markup.
How to preview Markdown
Start by typing or pasting Markdown into the editor. If you already have a file, choose one .md or .markdown file or drag it into the upload area. The browser reads the file as text and places the contents in the editor. The tool shows the filename, file size, character count, word count and estimated reading time so you can evaluate the document before exporting it.
Use split view when you want to edit and preview side by side. Use editor-only view when you need more room for writing. Use preview-only view when you want to review the rendered result on a smaller screen. On mobile, split view stacks the editor and preview vertically so both remain readable.
Standard Markdown and GitHub Flavored Markdown
Standard Markdown covers headings, paragraphs, emphasis, lists, blockquotes, inline code, fenced code blocks, links, images and horizontal rules. GitHub Flavored Markdown adds practical extensions used in many developer workflows, including tables, task lists and strikethrough.
This previewer supports those common patterns where they are implemented by the parser. That makes it useful for README drafts, issue templates, documentation tables and short technical notes. It does not promise identical output to every publishing platform because GitHub, static site generators, CMS editors and chat tools may apply different Markdown settings and CSS.
Tables, task lists and code blocks
Tables can become too wide for a phone screen, especially when headings or code values are long. ToolMint keeps preview tables in a horizontal scroll container instead of forcing columns to collapse into unreadable narrow text. Code blocks also scroll horizontally so long lines stay intact.
Task lists render as checkboxes in the preview. They are disabled because the preview is a rendering surface, not a task manager. Fenced code blocks preserve their text and language class when the parser provides one, but the tool does not execute code or fetch packages. Inline code remains visible inside normal paragraphs.
Markdown to HTML conversion
The Copy HTML action copies the sanitized HTML fragment generated from the current Markdown body. The Download HTML action creates a standalone HTML document with minimal readable styling for headings, code, blockquotes, images and tables. This is useful for sharing a rendered draft, checking the output in another browser or saving a quick local preview.
Generated HTML is still an export of your content, not a complete website template. If you are publishing to a CMS, documentation site or application, review the final platform output because its styles and Markdown settings may differ from the ToolMint preview.
Safe rendering and raw HTML
Raw HTML is disabled by design. If Markdown contains HTML such as <script> or <div onclick="...">, the preview treats it as visible text instead of executable markup. Links are filtered so unsafe URL schemes such as javascript: are not used. External links in generated preview HTML receive safe relationship attributes.
Images are allowed when they use safe URL patterns, but remote image URLs may still be requested by your browser when the preview displays them. ToolMint does not upload the Markdown document to its own servers, and analytics do not include document text, generated HTML, filenames, links, headings or code blocks.
Common Markdown mistakes
Many rendering problems come from small syntax issues. A table needs a separator row such as | --- | --- | after the header. A fenced code block needs matching opening and closing backticks. Nested lists need consistent indentation. A URL with spaces usually needs angle brackets or percent encoding.
Another common mistake is assuming raw HTML will behave the same everywhere. Some platforms allow it, some sanitize it and some disable it. ToolMint disables raw HTML for safety, so use normal Markdown syntax whenever possible. If you need to prepare links or query strings, the URL Encoder / Decoder can help. If you need to compare Markdown revisions, use the Text Diff Checker. If you need word and reading-time estimates for prose, use the Word Counter.
Privacy and local processing
Markdown parsing, preview rendering, copying and downloads happen in the browser. Uploaded files are read through browser file APIs and are not uploaded to ToolMint servers. Resetting the tool clears the editor and file information in the current tab, while refreshing or closing the tab removes the in-memory workspace.
Analytics are limited to privacy-safe interaction events such as file upload, view-mode changes, copying, downloading, loading the example and reset. They do not include Markdown content, generated HTML, filenames, headings, links, code blocks or private document text.
Limitations
The file-size guidance is about 5 MB for this browser tool. That is practical guidance, not a universal browser limit. Very large Markdown files can take longer to parse and render, especially on older phones or low-memory devices.
The preview is intentionally not a full documentation engine. It does not run plugins, execute embedded code, compile MDX components, syntax-highlight code with a theme, resolve local image files from an uploaded Markdown document or guarantee exact parity with GitHub, npm, a static site generator or a CMS. For structured data work, use the JSON Formatter, CSV to JSON Converter or JSON to CSV Converter. You can browse more utilities in the Developer category.
Related ToolMint tools
Use the Word Counter to measure document length, Text Diff Checker to compare Markdown revisions, JSON Formatter for structured examples, Base64 Encoder / Decoder for encoded snippets and URL Encoder / Decoder for safe link values.
The FAQ section below is generated from the ToolMint registry so visible answers and FAQ structured data stay synchronized.