Free tool
Markdown Reader by Twistag
Markdown Reader by Twistag is a free Chrome extension that renders Markdown files as clean, readable documents — with Mermaid diagrams, LaTeX math, syntax-highlighted code, dark mode and PDF export. Every file is processed locally inside your browser: nothing is uploaded, and there is no account, no advertising and no tracking.
What does Markdown Reader do?
It turns a raw .md file into a formatted, readable document the moment you open it in Chrome — no editor, no preview pane, no copy-and-paste into a web tool.
Markdown is where a lot of working context lives: specifications, architecture decisions, runbooks, research notes, the README you were sent five minutes ago. Opening one in a browser normally means reading the raw syntax, hashes and pipe characters and all, or switching to an editor just to see it properly.
With the extension installed, the file renders instead. Headings become headings, tables become tables, fenced Mermaid blocks become diagrams and LaTeX becomes typeset math. A small toolbar in the corner lets you switch theme, flip back to the raw source, copy the document, or export it to PDF.
How do I preview Markdown in Chrome?
Install the extension from the Chrome Web Store, then open any Markdown file in a tab — it renders automatically, with no further setup.
Add it to Chrome
Install Markdown Reader by Twistag from the Chrome Web Store. It is free, and there is no account to create or sign in to.
Open a Markdown file
Open a local or remote .md file in a tab, the same way you would open any other file or URL. Nothing else needs configuring first.
Read it, then take it with you
The document renders immediately. Use the toolbar to switch between automatic, light and dark themes, view the raw source, copy the text, or export a PDF.
What does Markdown Reader look like?
Rendered output is deliberately plain: a single measured column, generous line height, and diagrams and math rendered inline where they appear in the source.
What can Markdown Reader render?
Standard Markdown plus the three things that usually break in a browser preview: Mermaid diagrams, LaTeX math and syntax-highlighted code.
Mermaid diagrams
Fenced Mermaid blocks render as real diagrams rather than as code. Flowcharts, sequence diagrams and quadrant charts all draw inline, in the position they occupy in the source, so an architecture document reads as a document instead of a wall of diagram syntax.
LaTeX math
Inline and block mathematics are typeset properly, so notation embedded in a sentence sets on the same line as the surrounding prose. Useful for anything that mixes explanation with real notation — model documentation, evaluation write-ups, research notes.
Syntax-highlighted code
Fenced code blocks are highlighted by language. Long technical documents stay skimmable, because code reads as code at a glance rather than as an undifferentiated grey block.
Tables, quotes and collapsible sections
Tables render with proper column alignment and row banding. Blockquotes, ordered and nested lists, and collapsible details sections all render as you would expect, which matters for decision records and runbooks that lean on them for structure.
Light, dark and automatic themes
The theme control cycles between automatic, light and dark. Automatic follows your system setting, so a document opened at night is not a page of white light, and one opened in a bright room is not needlessly dim.
Copy, raw source and PDF export
The toolbar exposes three actions beyond theming: copy the document, switch to the raw Markdown source and back, and export the rendered page to PDF. The PDF keeps the rendered formatting, diagrams included, which makes it a reasonable way to send a document to someone without the extension.
Does Markdown Reader send my files anywhere?
No. Every file is parsed and rendered locally in your browser. Nothing is uploaded, and the extension makes no network calls with your document.
This is the part most worth checking before you install any extension that reads your files, so it is worth stating plainly: there is no account, no sign-in, no analytics and no advertising. Documents are not transmitted to Twistag or to anyone else, which means the extension is safe to point at a file you would not paste into a web tool — an unreleased specification, a client document, an internal decision record.
You do not have to take our word for it. Google independently verifies developer data declarations on the Chrome Web Store, and the listing shows that this developer “has disclosed that it will not collect or use your data.”
How does it compare to other ways of reading Markdown?
The trade-off is between formatting, privacy and effort. Reading raw source keeps the file private but is hard to read; pasting into an online viewer is readable but sends the file to a third party.
| Approach | Markdown Reader | Raw .md in a browser tab | Online Markdown viewer | Open in an editor |
|---|---|---|---|---|
| Renders formatting | Yes | No — raw syntax | Yes | Yes |
| Diagrams and math | Yes, inline | No | Varies by tool | Usually needs a plugin |
| File leaves your machine | No | No | Yes — uploaded or pasted | No |
| Works offline | Yes | Yes | No | Yes |
| Effort per file | Open the file | Open the file | Copy, paste, wait | Switch apps, open, preview |
| Cost | Free | Free | Free or freemium | Free or paid |
Who built Markdown Reader?
Twistag, an AI, data and product engineering company in Lisbon. We built it for ourselves first: Markdown is the format our project context, technical decisions and product specifications live in, and reading those documents well turned out to matter more than we expected once agentic systems started reading them too.
It is a small tool from the team behind Refraction, a code-generation product used by 20,000 engineers, and an AI communications assistant that runs as a Chrome extension inside the tools 6,000 utility employees already use. Building software people keep open all day is most of what we do; if you have something larger in mind, that is our product engineering practice.
What's changed?
Markdown Reader is at version 1.0.0, released on 16 August 2026.
- First public release on the Chrome Web Store.
- Renders local and remote Markdown files with Mermaid diagrams, LaTeX math and syntax-highlighted code.
- Automatic, light and dark themes, plus raw-source, copy and PDF export from the document toolbar.