Last updated: 2026-10-17 · Applies to MDViewer for Mac and iPhone
MDViewer does not collect, store, transmit, or sell any personal data. There are no accounts, no analytics, no tracking, no advertising, and no telemetry of any kind.
MDViewer renders Markdown files entirely on your device (Mac or iPhone). Parsing, syntax highlighting, math, and diagrams all run locally inside the app. The app has no servers and never sends your documents, filenames, or usage anywhere.
MDViewer runs in the operating system's app sandbox (the macOS App Sandbox on Mac; iOS's own app sandbox on iPhone) and only accesses files you explicitly open, plus — with your permission — folders you choose to grant (for example, the folder of a document that references local images, or a folder you browse in the app). It does not scan or read anything else on your device. A list of the folders you granted is stored only on your device, inside the app, so access can be restored on the next launch.
By default MDViewer makes no network connections. It contacts the network
only when a document you open references a remote (http/https)
image and you allow it via Preferences → Privacy (the default is to
ask). When you allow it, your device fetches those images directly from the servers that host
them — the same as any web page loading an image — which discloses your IP address to those
third-party servers. MDViewer itself receives nothing and stores nothing about this.
None. MDViewer bundles open-source rendering libraries (marked, Shiki, KaTeX, Mermaid, DOMPurify) that run locally; none of them phone home.
MDViewer is rated 4+ and collects no data from anyone, including children.
If this policy ever changes, the updated version will be posted at this URL.
Questions: open an issue at github.com/devicemanager/mdviewer.