Privacy

Privacy Policy & Disclaimer

This policy explains what the MailDeck website and the MailDeck app handle, and the disclaimer that applies to their use. The Japanese version is the original; this English version is a translation.

Effective: September 14, 2026 · Revised: September 24, 2026 · Operator: K386

Scope

This policy covers the MailDeck website operated by K386 (introduction, user guide and downloads) and the MailDeck app it distributes.

Please use MailDeck and this website only if you agree to this policy, including the disclaimer below.

What the website does not use

• Tracking cookies: none are set for visitors.
• External analytics: no Google Analytics or other third-party analytics scripts.
• Advertising: no ad tags or retargeting.
• Registration or forms: there is no place to enter your name, address or card details.

Server logs and counts

For stable operation and maintenance, the hosting provider may record standard access logs (IP address, time, User-Agent and so on).

This website also counts page views, daily visitors and downloads. It does not store IP addresses or User-Agents themselves. To avoid counting the same visitor twice on the same day, it uses a value that cannot be turned back into the original, and deletes that value after 2 days.

What the app connects to

MailDeck does not send usage data (telemetry) and does not contact any analytics service. It connects to only these two:

1. Google services: the Google services you open (Gmail, Calendar, Keep, Contacts and the sign-in page) and the Google profile picture shown in Gmail. To count unread mail, it asks each account's Gmail about every 5 minutes. What is sent is the same as when you use Google in a browser.
2. Update check: by design, 5 seconds after launch, every 30 minutes, and when you choose "アップデートを確認…" (Check for Updates) in the menu, it reads https://k386.sub.jp/MailDeck/api/version.json to see if a new version exists. Only what any HTTPS request carries is sent (your IP address and a User-Agent containing the MailDeck version), nothing about your accounts or mail. It may appear in the server logs above. Only when you press "アップデートして再起動" (Update and Restart) in the new-version window (from 1.3.3), it also downloads the new DMG from the same site. However, 1.3.1 does not make this request because of a defect.

Links in emails open in your default browser, not in MailDeck. What happens after that is up to the browser.

Google data and where it is stored

MailDeck displays Google's web pages in a separate area for each account.

• Password: you sign in on Google's page. MailDeck never stores or reads your Google password.
• Sign-in state: cookies and cache issued by Google are stored on your Mac, separately for each account.
• Settings: account display names, colors, window position and other settings are also stored on your Mac.
• Location: ~/Library/Application Support/maildeck. "MailDeckを初期化…" (Reset MailDeck) in the app's settings removes accounts and sign-ins.

The developer never receives your mail, events, contacts or sign-in information.

Disclaimer

The developer (K386) accepts no liability whatsoever for any direct, indirect, incidental, special or consequential damages, loss or corruption of data, failure of computers or peripherals, business interruption, loss of profits, or any other damage or disadvantage arising from the use of, or inability to use, this website or the MailDeck app (the "App").

The App is provided "as is", without any warranty as to its accuracy, completeness, timeliness, usefulness, fitness for a particular purpose or safety.

The App displays Google's web services and is not provided or endorsed by Google. Changes to Google's services may cause part or all of the App to stop working.

Changes to this policy

If this policy changes, this page will be updated along with the revision date.

Contact

For questions about this policy or MailDeck, please email:

info@k386.sub.jp

MailDeck is developed and run by one person, so a reply may take a few days.