Md viewer: open an .md file and read it formatted

An .md file is a text file written in markdown: ordinary words with a few marks among them saying which line is a heading, which words are emphasised, and where a list or a table begins. Because it is plain text, almost anything will open it and almost nothing will format it. Double-click one on your desktop and you will most likely get a text editor showing you the marks themselves — hashes in front of headings, asterisks around words, pipe characters between the cells of a table. Nothing is wrong: that is the file being read correctly and shown raw. What you usually wanted was the file read and laid out, and that is what this page is for.

Four ways to get a document in

Choose a file from your machine with the file picker. Drag one out of a folder and drop it onto the page. Paste text straight in as a new document, which is the quickest route when what you have is on your clipboard rather than in a file. Or hand it the address of a raw markdown file on the web and let it fetch that one. The fourth has a real limit worth knowing before you try it: the fetch runs from your own browser, so it reaches only addresses whose host allows being read from another site. Raw file addresses on the common code hosts generally do; an ordinary web page generally does not. When it cannot, saving the file and opening it, or copying the text and pasting it, always works.

It renders rather than displays

Opening a document here formats it. Headings arrive at their sizes, lists indent, and a table is a table with ruled columns rather than a row of pipe characters. Code blocks are set in a monospaced face and coloured by language when the language is named after the opening fence. Formulas written in TeX are drawn as formulas. Diagrams written as text in a mermaid block are drawn as diagrams. Task lists arrive as boxes, ticked or empty, exactly as the file has them. And nothing inside a document is allowed to run: any script written into it is removed before you are shown anything.

The file is opened by the browser tab you are looking at and goes nowhere else. There is no upload, no account and no server keeping a copy — what you open is held in your own browser's storage and is still there the next time you visit in the same browser. Clearing your browser data clears it, which is the other half of the same fact: there is no copy anywhere else, so export anything you need to keep.

The page you land on is the editor as well as the viewer. Once a document is open you can type in it from either side, the markdown or the formatted view, search and replace inside it, watch the line, word and character counts move as you go, put two documents beside each other to see what differs, and export the result as markdown, as a single HTML file or as a PDF. If you only came to read something, none of that is in your way — it is simply there when you want it.