隐私政策

What Folio.md sends to us, why, and how we handle it.

本页面目前仅提供英文版。

Effective date: September 23, 2026

Folio.md is a Markdown editor made by Cythrus Software ("we", "us"). It is designed to work on your own computer: your documents stay with you, and the app talks to our servers only for a few narrow reasons. This page explains what Folio.md and this website send to us, why, and what we do with it.

1. Summary

  • Your documents never leave your computer unless you choose a feature that sends them somewhere (for example, syncing to your own Google Drive or OneDrive account). Even then, they go directly from your computer to that service, not to us.
  • To run the free trial and to check licenses, the app sends us an anonymised device identifier and, for the web version, your license key and a few details about the device.
  • Crash reports are sent only when you choose to send one, and you can read the whole report before sending it.
  • The app contains no advertising and no usage-tracking or analytics code. We do not record what you type, what you read, or how you use the app.
  • We do not sell or share your information with third parties, other than the service providers listed in section 8.

2. Information the app sends to us

2.1 Trial and license checks

To manage the 30-day free trial and, for the web version, your paid license, the app contacts our license server. Depending on what you are doing, it sends the following.

  • Device identifier. A one-way hash (SHA-256) of an identifier that Windows or macOS assigns to your computer. The original identifier is never sent, and the hash cannot be turned back into it. It lets us tell devices apart without knowing who you are. Starting a trial sends this identifier and nothing else.
  • License key (web version only) when you activate the app, when it re-checks the license periodically, and when you manage your registered devices.
  • Device details when you activate (web version only): the operating system type (Windows or macOS), your computer's name as set in the operating system, and a device name you can optionally type in yourself. These appear in the list of registered devices so that you can recognise which computer is which. A computer's name can contain your own name if you named it that way.

No other information about you or your computer is sent for license purposes.

2.2 Crash reports (only if you send one)

If Folio.md crashes, it can show you a report and ask whether you want to send it to us. Nothing is sent unless you press the send button. A report contains:

  • the technical details of the error (the error type, message and stack trace);
  • the app version, the operating system name and version, the processor architecture, the .NET runtime version and the number of processor cores;
  • the folder the app is installed in and the folder where it stores its settings, which can include your Windows or macOS user name;
  • any comment you write and any files you choose to attach.

Before the report is saved, strings that look like passwords, tokens or keys are masked on a best-effort basis in the error details. Your own comment and attached files are sent exactly as you provide them and are not masked, so please check them before attaching.

When a report arrives, our server also records the IP address it was sent from and stores it with the report. We use it only to prevent and investigate abuse of the crash-report service. It is not part of the report you review before sending.

3. Information we do not collect

  • The content of your documents, your keystrokes, your file names, or your search terms.
  • Your browsing or reading history, or statistics about how you use the app.
  • Nothing is collected by advertising or analytics software, because the app contains none.

4. Purchases

4.1 Microsoft Store version

If you install Folio.md from the Microsoft Store and subscribe there, Microsoft handles the purchase and payment. The app asks Windows only whether an active subscription exists and when it expires, and it does that on your computer. It does not send that information, your Microsoft account details, or any payment details to us, and we do not receive them from Microsoft. Microsoft's privacy statement applies to the Store purchase.

5. Features that connect your computer to other services

Some optional features connect directly from your computer to a service you choose. We are not part of that connection and do not receive the data that passes through it.

  • Cloud sync. You can sync a folder with your own Google Drive or OneDrive account. The sign-in tokens for that account are stored only on your computer, in encrypted form, and are never sent to us. Your files travel directly between your computer and the cloud service, under that service's privacy policy.
  • AI chat, MCP servers and external tools. If you configure an AI service or an external program, whatever you choose to send goes directly from your computer to that service or program.
  • Link previews and images from the web. When a document contains links or images hosted on the web, the app can fetch them to show a preview. Those requests go straight from your computer to the website in question, just as a web browser would. Our servers are not involved.

6. Why we use the information

  • To run the free trial and to check and manage licenses, including the number of devices registered to a license.
  • To deliver license keys and respond to purchase-related questions (web version).
  • To investigate crashes and fix defects (crash reports).
  • To prevent abuse of the crash-report service (the IP address a report was sent from).
  • To answer your support requests.

We do not use the information for advertising or profiling.

7. Where the information is stored and for how long

  • Location. Our servers run on Amazon Web Services in the Tokyo region (Japan). Data is stored in encrypted form.
  • License and trial records are kept for as long as they are needed to manage the trial or license, and for a reasonable period afterwards so that we can handle support questions and reactivations.
  • Crash reports are deleted automatically 180 days after we receive them.
  • Email you send us is kept as long as needed to deal with your request.

8. Sharing with others

We do not sell, rent or trade your information, and we do not share it with third parties for their own purposes. The following companies process data on our behalf, or handle a purchase as the seller, each under its own privacy policy:

  • Amazon Web Services: hosting of our license server and crash-report storage.
  • Cloudflare: delivery of this website.
  • Microsoft: seller and payment processor for the Microsoft Store version.

We may disclose information if required to do so by law.

9. Your choices and rights

  • You can use the app without ever sending a crash report.
  • You can remove a device from your license at any time from the license screen in the app (web version).
  • You can ask us to show you, correct or delete the information we hold about you by writing to the address in section 12. To find your license record we will need your license key or the email address used at checkout.

10. This website

This website uses no analytics or tracking cookies. Cloudflare, which delivers the site, may process connection information such as your IP address for security and performance reasons under its own privacy policy.

11. Changes to this policy

When we change this policy, we update it on this page and change the effective date at the top.

Revision history

  • September 23, 2026: first published version.

12. Contact

Cythrus Software
Privacy inquiries: contact@cythrus-software.com