Privacy policy
Effective 2026-10-18. This policy explains what personal information Chyuo (operated by Yucho Ho, trading as Chyuo, "we") collects through its apps and websites, what we do with it and the choices you have. If you are in Japan, the Japanese version at /ja/privacy applies to you.
1. What we collect
- Account: your email address, your name if you give one, and the identifier our identity provider assigns you when you sign in.
- Content you add: the photos, documents, text and other content you put into an app, and the information the app extracts from it (for example the attributes of an item in a photo).
- Purchases: whether your account has an active purchase or subscription, which product, and the store's or payment processor's reference for it. Card numbers are handled by Apple, Google or Stripe and never reach us.
- Technical data: logs of requests to our services, error reports and performance measurements, including IP address, device and app version. We use no advertising identifiers and no third-party analytics cookies on this website.
- Support: what you send to support@chyuo.com.
2. What we use it for
To provide the apps and keep you signed in; to extract information from your content, which is the point of some apps; to grant what you paid for; to keep the services reliable and secure; to answer you; and to meet legal obligations such as tax records. We do not sell personal information, we do not share it for advertising, and we do not use your content to train AI models.
3. Who processes it for us
We run the apps on services operated by other companies, which process data only on our instructions and for the purposes above:
| Provider | What for |
|---|---|
| Zitadel | sign-in and accounts |
| Fly.io | running the apps' servers (Tokyo region) |
| Neon | the apps' databases (United States) |
| Cloudflare | file storage, this website, mail routing, network security |
| Anthropic and Voyage AI | extracting information from and indexing your content, when an app does so |
| Apple, Google and Stripe, with RevenueCat | purchases and subscription status |
| Grafana Labs | logs, error reports and performance data |
| Resend | the emails the apps send you |
4. Where it is stored
Our databases and file storage are in the United States, and some processing happens in Japan and wherever the providers above operate. If you use the apps from outside the United States, your information is transferred there. We rely on the providers' contractual commitments to protect it.
5. How long we keep it
For as long as your account exists. When you delete your account, your account data and content are deleted within 30 days, except what we must keep for legal reasons (such as purchase records, which we keep for seven years) and backups, which expire on their own schedule. Technical logs are kept for up to 90 days.
6. Your choices and rights
You can read, correct, export and delete your information. Until the apps have these controls built in, email support@chyuo.com from your account's address and we act within 30 days, after confirming it is you. We will not treat you differently for exercising a right. If you live in California or another US state with a privacy law, these are the rights those laws give you; we do not sell or share personal information as those laws define it, so there is nothing to opt out of.
7. Children
The apps are not directed at children under 13, and we do not knowingly collect their information. If you believe a child has given us information, contact us and we delete it.
8. Security
Data travels encrypted and is stored with the providers above, access to it is limited to what operating the apps requires, and credentials are kept out of the code. No system is perfectly secure; tell us if you find a problem.
9. Changes
We may update this policy. The current version is always here with its effective date, and we tell you in the app or by email about material changes before they apply.
10. Contact
support@chyuo.com. Our business details are on the business page.