Privacy Policy

This tool (the “Service”) respects the privacy of your personal information and data, and works to manage data safely.

This is an English translation of the Japanese privacy policy. If there is any difference between the two, the Japanese version prevails.

Your data stays with you

The Service is designed with privacy and safety in mind.

Nothing is sent to external servers

Files you load and the data behind the charts you create are never uploaded to an external server. All processing happens inside your browser on your own device, so your data is not exposed over the internet.

Your data is kept only in your browser

Data is stored only in your own browser’s storage (such as LocalStorage). No third party, including the developer, can access it.

Trusted libraries

We use widely used, standard libraries such as D3.js for drawing charts and SheetJS for reading Excel files. These also run only in your browser.

Analytics and cookies

To understand how the Service is used and to improve it, we may use cookies and analytics tools such as Google Analytics.

Data collected: traffic data (such as time of access, pages viewed and browser information) is collected anonymously. This data does not identify you personally.

Turning off cookies: you can refuse cookies in your browser settings.

Advertising (Google AdSense)

The Service uses Google AdSense, an advertising service provided by Google, a third-party vendor.

Third-party vendors, including Google, use cookies to serve ads based on your past visits to this Service and other websites.

You can turn off personalized advertising in Google Ads Settings. You can also opt out of third-party vendors’ use of cookies for personalized advertising at www.aboutads.info.

For details on how Google uses cookies in advertising, see Google’s advertising policies.

Personal information in inquiries

When you contact us through our contact form, you may provide personal information such as your name or email address.

Purpose: we use it only to reply to your inquiry and to contact you about improving the Service.

Sharing with third parties: except as required by law, we will not disclose or provide your personal information to third parties without your consent.

Changes to this policy

We may update this privacy policy as needed. Changes take effect when they are posted on this site.