Eidendo Inc. ("we") sets out below how information is handled on the StudyRiver website, web app, MCP tools and related channels (the "Service").
Learning records — the skills you choose, the settings used to generate problems, when you practiced, which answers were right or wrong and how hard it felt — are saved in your browser's local storage. You can export and import them as a JSON file.
If you clear your browser data, the records on your device may be lost. We recommend backing up the JSON file regularly yourself.
If you use StudyRiver MCP from Claude, ChatGPT, Codex or another external AI service, your conversation and any JSON file you attach may be sent to that AI provider and are handled under that provider's terms and privacy policy. Please choose for yourself what you share.
We may use Google Analytics to understand how the site is used and to improve its content and usability. Browsing information may be sent to Google through cookies or similar technologies; we do not link it to learning records. Google's policies apply to that data.
To keep the Service free, we may use Google AdSense on the StudyRiver website and web app. Google or other ad vendors may use cookies and similar technologies to collect browsing information, device information and ad impression or interaction data. We do not link this to learning records in the web app. You can learn how Google uses information in Google's policy.
Because minors may use the Service, ads are served in line with Google's age-appropriate treatment and applicable laws and policies. Choices about ad settings and personalization are available in Google's My Ad Center. Ads appear only on web pages — never on the printed worksheets.
We may use cookies and other device identifiers for advertising or analytics. Where consent is legally required, we show choices through Google's consent tools or a Google-certified consent management platform. You can also disable cookies in your browser settings, though some features may then display differently.
We may use the APIs of TikTok, Instagram and YouTube to post educational content created by StudyRiver to accounts that we own and manage.
The permissions we request are limited to what is needed to post our own content and to confirm basic information of the connected accounts. We do not collect personal data of viewers or third parties, nor direct messages. OAuth tokens and the IDs of posted videos are kept in a private environment only as long as needed to prevent duplicate posts and to operate.
Except where required by law, we do not provide personal information to third parties without the person's consent.
You can delete web app learning records in your own browser. To confirm or delete data held by us, please contact us:
Operator: Eidendo Inc. / StudyRiver
Email: study@eidendo.co.jp
We may revise this policy as laws or the Service change. Important changes will be announced on this page. If versions in different languages differ, the Japanese version prevails.