How to Write and Preview Markdown Online
Getting started with this online Markdown editor takes seconds. Open the tool and you are presented with two editing modes: a WYSIWYG rich editor and a Monaco raw code editor. Both modes write the same underlying Markdown — the difference is how you interact with it.
In WYSIWYG mode, a formatting toolbar sits above the writing area. Click the B button to bold selected text, the heading buttons to set H1 through H6, and the list buttons for ordered and unordered lists. You never need to type a single asterisk or hash — the editor handles the syntax for you while you focus on the words.
In Monaco mode, you write raw Markdown syntax directly. Monaco is the same editor that powers Visual Studio Code, which means you get syntax highlighting, multi-cursor editing, find-and-replace, and keyboard shortcuts you already know. This mode is ideal when you are working with precise formatting, pasting Markdown from another source, or troubleshooting rendering issues.
The live preview pane updates in real time on every keystroke regardless of which mode you are in. You see the rendered output — headings, tables, code blocks, bold, italic, blockquotes — exactly as a Markdown renderer would display it. No need to switch tabs or click a preview button.
To work with an existing file, click Import and select any .md file from your computer. The file contents load instantly into the editor. When you are done writing, click Export to download your content as a .md file, ready to commit to a repository, upload to a documentation platform, or share with a colleague.
What Is Markdown?
Markdown is a lightweight markup language created by John Gruber in 2004, with significant contributions from Aaron Swartz. The core philosophy is simple: Markdown source text should be readable as plain text even before it is rendered. A heading marked with # still looks like a heading in a plain text file. Bold text wrapped in **asterisks** still communicates emphasis. The syntax was designed to mirror conventions people already used when writing plain-text email.
Under the hood, Markdown is converted to HTML by a parser. The parser reads Markdown syntax tokens — hashes, asterisks, backticks, brackets — and emits the corresponding HTML elements. This means Markdown is ultimately just a friendlier way to write HTML without embedding angle brackets everywhere.
Developers love Markdown for several reasons. First, it is version-control friendly. Because Markdown is plain text, Git diffs show exactly what changed — a sentence, a word, a heading. Binary formats like .docx produce opaque diffs. Second, it is portable. A .md file opens correctly in any text editor without specialized software. Third, it is widely supported: GitHub renders Markdown automatically in repositories, READMEs, issues, and pull request descriptions. Notion, Confluence, Slack, Discord, and dozens of other tools accept Markdown input. Fourth, it is fast. Experienced writers move through headings, lists, and code blocks without taking their hands off the keyboard.
Over the years, several Markdown flavors have emerged. CommonMark is a standardized specification that resolves ambiguities in the original Gruber spec. GitHub Flavored Markdown (GFM) extends CommonMark with tables, task lists, strikethrough, and auto-linked URLs. MultiMarkdown adds footnotes, metadata, and table of contents generation. Most tools and renderers support at minimum CommonMark, with GFM being the de facto standard for developer documentation.
WYSIWYG vs Raw Markdown: Which Mode Should You Use?
The choice between the WYSIWYG editor and the Monaco raw editor depends on your background, your workflow, and the type of content you are writing.
Choose WYSIWYG when: you are new to Markdown and want to learn by doing. The toolbar makes formatting discoverable — you can bold text, create a table, or add a link without memorizing any syntax. WYSIWYG mode is also ideal for non-technical collaborators such as product managers, technical writers, and content authors who need to produce Markdown for a documentation site or CMS but prefer a word-processor interface. If you are writing a long document with many headings and mixed formatting, the WYSIWYG mode reduces cognitive overhead because you see the final rendered appearance as you type.
Choose Monaco raw mode when: you are a developer who already knows Markdown syntax and wants full control. Monaco lets you paste raw Markdown from a clipboard, edit frontmatter YAML blocks, and write complex nested list structures that WYSIWYG editors sometimes misinterpret. The Monaco editor also handles large files more gracefully — if you are pasting a 500-line README or a full API reference page, the code editor environment feels more natural. Raw mode is also better when you need to see exactly which syntax tokens are present, because rendering can obscure whether text is actually bold or just appears bold due to a font.
Switching between modes: you can toggle between WYSIWYG and Monaco at any point. The editor preserves your content when you switch. This is useful when you start drafting in WYSIWYG, then switch to Monaco to fine-tune a table or a fenced code block that the rich toolbar makes awkward to edit precisely.
For teams that mix technical and non-technical contributors — for example, an engineering team writing documentation alongside a product team writing release notes — having both modes available in the same tool eliminates the need to use separate applications for different audience segments.
Markdown Live Preview: See Your Content Render as You Type
The live preview feature is one of the most practical aspects of this online Markdown editor. As you type in either editing mode, the right-hand pane renders the output in real time. There is no delay, no refresh button, and no compile step.
Live preview matters because Markdown syntax errors are silent. If you accidentally leave a code fence unclosed — forgetting the closing triple backtick — everything below it gets rendered as a code block. Without a live preview, you would only discover this error after exporting the file and opening it in another tool. With live preview, the rendering problem is immediately visible and you fix it in seconds.
The preview also helps with tables. Markdown tables require careful column alignment and pipe characters. A misaligned column or a missing pipe produces a broken table. Seeing the rendered table live as you type columns and rows lets you catch these issues row by row rather than discovering a broken table after the document is complete.
For content authors writing for the web — blog posts, documentation pages, README files — the live preview answers the question "will this look right?" before the content ever reaches a CMS or a static site generator. You see heading hierarchy, paragraph spacing, blockquote styling, and image alt text rendering exactly as a compliant Markdown renderer would display them.
This is the same workflow professional technical writers use in paid tools. Having it available free in the browser, with no installation required, makes previewing Markdown online accessible to anyone.
Writing README Files and Technical Documentation
README files are the front page of a software project. GitHub renders the README.md file at the root of any repository automatically, making it the first thing visitors read. A well-structured README increases contributor confidence, reduces onboarding time, and communicates the purpose and scope of the project at a glance.
A complete GitHub README typically includes: a project title and one-paragraph description, a badges row (build status, license, version), an installation section with shell commands in fenced code blocks, a usage section with examples, a configuration reference, a contributing guide link, and a license footer. This Markdown editor is ideal for drafting all of these sections because the live preview shows exactly how badges, code blocks, and tables will render on GitHub.
Code blocks are essential in technical documentation. Wrap shell commands and code samples in fenced code blocks using triple backticks followed by the language identifier:
```bash
npm install my-package
```The language identifier enables syntax highlighting in most Markdown renderers including GitHub, GitLab, and documentation generators like Docusaurus, MkDocs, and VitePress.
Tables in Markdown use pipe characters and hyphens to define columns and rows. They are commonly used in README files for configuration option references, environment variable listings, and API parameter descriptions. The live preview in this editor shows rendered tables immediately, so you can verify column widths and alignment as you build the table row by row.
Images in Markdown use the syntax . For GitHub README files, screenshots and architecture diagrams are stored in the repository (often in a docs/ or .github/ folder) and referenced with a relative URL. The alt text is important both for accessibility and for SEO when documentation pages are indexed by search engines.
Beyond GitHub READMEs, this editor works well for any documentation that targets a Markdown-based pipeline: Docusaurus, MkDocs, Hugo, Astro, Eleventy, or any static site generator that accepts .md files as content sources.
Markdown Syntax Reference
Below is a quick reference for the most commonly used Markdown syntax elements. All of these are supported in the editor's live preview.
| Element | Syntax | Output |
|---|---|---|
| Heading 1 | # Heading | Large heading |
| Heading 2 | ## Heading | Section heading |
| Heading 3 | ### Heading | Subsection heading |
| Bold | **text** | text |
| Italic | *text* | text |
| Bold italic | ***text*** | text |
| Strikethrough | ~~text~~ | |
| Inline code | `code` | code |
| Fenced code block | ```lang | Highlighted code block |
| Unordered list | - item | Bullet list |
| Ordered list | 1. item | Numbered list |
| Task list | - [ ] task | Checkbox list (GFM) |
| Blockquote | > text | Indented quote block |
| Horizontal rule | --- | Thematic break line |
| Link | [label](url) | Hyperlink |
| Image |  | Inline image |
| Table | | col | col | | Data table (GFM) |
| Footnote | [^1] | Numbered footnote |
Task lists, tables, and strikethrough are GitHub Flavored Markdown (GFM) extensions and are supported by GitHub, GitLab, Notion, and most modern Markdown renderers. If you are targeting a stricter CommonMark renderer, stick to headings, emphasis, lists, code blocks, blockquotes, links, and images.
Exporting Markdown Files for Documentation Pipelines
Once you have finished writing, the Export button downloads your content as a .md file. This file is immediately usable in any tool or pipeline that accepts Markdown input.
GitHub and GitLab: commit the .md file directly to your repository. GitHub renders README.md, CONTRIBUTING.md, CHANGELOG.md, and any Markdown file in a docs/ directory automatically in the browser.
Documentation generators: Docusaurus, MkDocs, VitePress, and Hugo all ingest .md files as page content. Add frontmatter YAML at the top of your exported file (title, description, sidebar position) and the documentation generator handles navigation and theming automatically.
Notion and Confluence: both platforms support Markdown import. In Notion, paste Markdown content directly into a page or use the import function to load a .md file. Confluence accepts Markdown through the Markdown Macro plugin or through direct paste in many editor versions.
CMS platforms: Ghost, Contentful, Sanity, and many other headless CMS platforms accept Markdown as a content format, either natively or through a Markdown field type. Your exported .md file drops directly into these workflows.
Static site generators (Astro, Next.js, Nuxt): these frameworks process .md and .mdx files in their content collections or pages directories. Export from this editor, add a frontmatter block, and your page is ready to render.
Pair this tool with the Diff Viewer when you need to compare two versions of a Markdown file — paste both versions into the diff tool to see exactly what changed between drafts or between versions in a pull request.
Markdown Editor Use Cases for Teams
Individual developers are the most obvious users of an online Markdown editor, but teams across disciplines find practical value in a fast, browser-based writing and preview tool.
Developers writing READMEs: the most common use case. A developer opens the tool, drafts a README with installation instructions, usage examples, and a configuration table, previews it live to verify rendering, and exports the .md file to commit. The Monaco mode is particularly useful here because developers are comfortable with code editors and want to paste shell commands, code snippets, and YAML configuration blocks directly.
Technical writers: documentation teams that work in Markdown-based systems (Docs-as-Code workflows, MkDocs sites, Docusaurus portals) use the WYSIWYG mode to draft content quickly, then export to their documentation repository. The live preview lets them verify that admonitions, code blocks, and tables render correctly before committing.
Blog authors: many blog platforms — Ghost, Hashnode, Dev.to, and Markdown-based static sites — accept Markdown content. Writing in a dedicated Markdown editor with live preview is faster than writing directly in a CMS editor, especially for posts with heavy formatting, multiple code examples, or embedded images.
API documentation teams: API reference pages, endpoint descriptions, and SDK guides are often written in Markdown and fed into tools like Redoc, Swagger UI, or ReadMe. Drafting in this editor with live preview ensures the documentation structure is correct before it enters the documentation build pipeline.
Students and educators: Markdown is increasingly used in academic contexts — Jupyter notebooks, course notes, and assignment submissions often use Markdown for prose formatting. A free online editor with no installation requirement is accessible from any classroom computer or shared machine.
When your workflow involves structured data alongside documentation — for example, generating a JSON configuration reference to embed in a README — the JSON Editor pairs well with this Markdown editor for a complete documentation workflow. Koodisi offers both tools and more as part of a free developer toolset.
Frequently Asked Questions
- Is this Markdown editor free to use?
- Yes. This is a completely free online Markdown editor with no registration, no account, and no usage limits. Open the tool and start writing immediately.
- Does the editor save my content automatically?
-
Content is preserved in the browser session while the tab is open. To persist your work beyond the session, use the Export button to download a
.mdfile. There is no cloud save or server-side storage — your content stays local to your browser. - Does the editor support GitHub Flavored Markdown (GFM)?
- Yes. The live preview renders GitHub Flavored Markdown including tables, task lists (checkboxes), strikethrough text, fenced code blocks with language identifiers, and auto-linked URLs. These are the extensions GitHub adds on top of CommonMark, and they are fully supported in the preview pane.
- Can I export Markdown as HTML instead of a .md file?
-
The Export button currently saves your content as a
.mdfile. To convert Markdown to HTML, you can paste the rendered preview content or use a command-line tool likepandocor a Markdown-to-HTML converter on your exported file. HTML export is a planned feature. - Can I paste images into the editor?
-
Markdown references images by URL rather than embedding them as binary data. To include an image, upload it to a hosting service (GitHub, Imgur, Cloudinary, your own CDN) and reference it in your Markdown with
. The live preview renders linked images from external URLs in real time.