Privacy policy

Last updated: 5 November 2026. The Japanese version is the binding one.

Shironuki (operated by Shige Mizuno, "we") removes the background from product photos. This policy describes what we collect and what we do not, exactly as the service works.

1. What we collect

There is no account and we never ask for your name or e-mail address. We collect three things only.

• A browser id (cookie): on your first visit we store a random string in a cookie named shironuki_id. It counts the free allowance (100 photos a month) per browser and contains nothing that identifies you. It lives for 365 days and disappears when you clear your browser's cookies (a new id is then created).
• A hash of your IP address: to stop the free allowance being reused by clearing cookies, we record a SHA-256 hash of your IP address (the upper 64 bits for IPv6) combined with a secret string, together with a monthly count. The hash cannot be turned back into the address, and we do not store the address itself. One address is limited to 5,000 photos a month.
• The photos you upload: we receive the image data for the time it takes to remove the background. See section 3.

2. What we use it for

• Counting the free allowance and stopping use beyond it (the cookie, the IP hash)
• Removing the background and returning the result (the photos)
• Protecting the service from abuse and excessive load (the IP hash)

3. Your photos

• A photo is used only to remove its background and is discarded the moment the result is returned. We do not store photos. The service is built without any storage for them.
• Photos are never used to train or improve AI or machine-learning models.
• The background removal itself is performed by Cloudflare Images, a service of Cloudflare, Inc. (United States). The photo is processed on their servers and, under their terms and privacy policy, is not retained after processing.
• The white-background JPEG and the zip file are produced inside your browser and never sent to us.

4. Where and for how long

• The monthly count behind the cookie id and the monthly count behind the IP hash are kept on Cloudflare, Inc. servers, which may be outside Japan. Both are per calendar month (Japan Standard Time); the first use in a new month replaces the record, and the previous month's count is gone.
• Photos are not stored (section 3).
• We keep no access logs. Cloudflare, Inc. handles connection data as part of running its network, under its own policy.

5. Sharing and processors

We never sell or hand over what we collect. Image processing and hosting are entrusted to Cloudflare, Inc. (United States), which handles the data only within that role; see Cloudflare's privacy policy. Disclosure required by law is the exception.

6. Analytics and advertising

We currently use no analytics tool and no advertising. If that changes, this policy will be updated with the tool's name and purpose.

7. What the paid plans will add

When the paid plans (in preparation) open, we will handle an e-mail address for signing in and payment details for billing. Card details are handled by our payment processor, Stripe, and never stored by us. This policy will be updated when the plans open.

8. Access, correction and deletion

All we hold is a monthly count behind a cookie id and behind an IP hash, neither of which can be linked to a person. To drop the record behind your cookie id, clear the cookie in your browser. For anything else, e-mail us at the address below.

9. Contact

Shironuki — Shige Mizuno
E-mail: support@shironuki.com
Postal address and phone are in the legal notice.

10. Changes to this policy

When what we collect or how we handle it changes, this page is updated and the date at the top is renewed. Important changes are also announced on the tool's page.