Turn Any Text Editor into a Powerful Markdown Viewer with Markdeep

Markdeep is a pure‑text plugin that renders Markdown syntax, tables, mathematical equations, and charts directly in a web page without requiring any installation or network connection.

Project homepage: https://casual-effects.com/markdeep/

Below is a side‑by‑side view of a plain‑text editor and the rendered result in a browser.

Markdeep is extremely easy to use and does not require any plugins or online services. Adding the line <!-- Markdeep: --> at the end of a plain‑text file turns it into a full‑featured Markdown document.

How to Use Markdeep

Open any text editor, write your content, then append the simple marker line at the bottom. Save the file with the .md.html extension.

<!-- Markdeep: --><style>body{visibility:hidden;white-space:pre;font-family:monospace}</style><script src="markdeep.min.js" charset="utf-8"></script><script src="https://casual-effects.com/markdeep/latest/markdeep.min.js" charset="utf-8"></script><script>window.alreadyProcessedMarkdeep|| (document.body.style.visibility="visible")</script>

If you want Unicode support, add the meta tag <meta charset="utf-8"> at the top of the document.

Drag the file into a browser or double‑click it to view the formatted output, even offline. To keep the formatting offline, store markdeep.min.js alongside the document.

Appending ?noformat to the URL shows the raw Markdeep source.

What Markdeep Can Do

Markdeep supports everything that Markdown does and is widely used in both industry and academia. It can produce a variety of document types:

API documentation

Course outlines

Game design documents

Homework assignments

Presentation slides (PPT)

Software library websites

Personal blogs

Resumes

Academic papers

Examples of these outputs are shown below.

Markdeep’s source code is open‑source ( markdeep.js, over 5,000 lines). The author maintains the project as a hobby, fixing bugs and adding features regularly since its first release in October 2015.

In short, Markdeep offers a convenient, offline‑friendly way to write and preview Markdown‑style documents with rich features such as tables, LaTeX math, and ASCII‑art charts, all from a simple text editor.