Is It Safe to Open a .md File?
Can a Markdown file have a virus?

Short answer: a .md file is plain text, so opening it runs nothing

A Markdown file is just text with a few markers in it, the #, *, and - you see in the source. There is no program inside it and nothing to execute. When you open a .md, a text editor or a Markdown reader simply displays that text. The file cannot install anything, change settings, or run on its own, because there is no code in it to run. New to what those markers are? See why AI uses Markdown.

Can a Markdown file contain a virus or malware?

Not the way an executable can. Markdown has no scripting, no macros, and no executable payload, so a .md cannot infect your machine by being opened. It helps to compare it to the file types people actually worry about:

The worst a .md can do is contain something: a link, or, in some renderers, a bit of raw HTML. That is where the two mild risks come from.

The real (mild) risks: links you click, and raw HTML in some renderers

• Links inside the file. A .md can hold a link that points somewhere bad, the same way any text or email can. The file is still safe; the risk is only if you click a malicious link. Hover to check where a link goes before clicking, exactly as you would anywhere else.
• Raw HTML in the preview. Markdown lets you embed raw HTML, and while most modern renderers ignore or neutralize anything risky, not all do. If you are cautious about a file from an unknown source, read the source (the raw text) first instead of jumping straight to a rendered preview.

Both of these are ordinary web-safety habits, not something unique to Markdown. The file will not run on its own; you just avoid clicking things you should not.

How to open a .md safely: read the source, locally, with nothing uploaded

Two simple habits cover the caveats above. First, open the file locally rather than uploading it to a random online viewer, because an online tool sends your file to its server to render it. Second, look at the source (raw text) first, so you see exactly what is in the file, links and any raw HTML included, before it is rendered.

This is a good fit for NoteLoom: it opens the .md straight off your disk in the browser, its source view shows the raw text with nothing executed, and because it reads the file locally, nothing is uploaded to any server. That makes it a calm way to inspect an unfamiliar .md before you trust what is inside. For the different local vs cloud tradeoff, see the local-first Markdown editor.

To be clear about the boundaries: NoteLoom does not scan for viruses and has no AI. A plain-text .md does not need virus scanning the way a program would; NoteLoom simply shows you the file locally and saves it back, and the reading stays with you.

How you use it: open app.noteloom.cc in Chrome / Edge / Arc, mount the folder the file is in, and open it in source view to read the raw text. Nothing leaves your device, no cloud, no account.

Is it safe to open a .md you got from AI or downloaded?

• From an AI answer (ChatGPT, Claude, and so on): yes. It is just the Markdown text of the answer, plain text, safe to open. See how to open the Markdown ChatGPT gives you.
• Downloaded or from a repo: the .md itself is safe text, like a README or docs file. Apply the same two habits, do not click unknown links, and read the source if you are unsure, and you are fine.

Once you know it is safe, the next question is usually just how to read it comfortably, which is covered in how to open a .md file.