Privacy Policy

Tetsuro Miyagawa built the sand1 app as a Free app. This SERVICE is provided by Tetsuro Miyagawa at no cost and is intended for use as is.

This page is used to inform visitors regarding my policies with the collection, use, and disclosure of Personal Information if anyone decided to use my Service.

If you choose to use my Service, then you agree to the collection and use of information in relation to this policy. The Personal Information that I collect is used for providing and improving the Service. I will not use or share your information with anyone except as described in this Privacy Policy.

The terms used in this Privacy Policy have the same meanings as in our Terms and Conditions, which is accessible at sand1 unless otherwise defined in this Privacy Policy.

Anonymous by Design

sand1 is designed to be used anonymously.

No account registration is required. I do not collect your name, email address, or phone number.

Your precise location is never sent to my servers. Before a post leaves your device, its coordinates are rounded to a grid of roughly 150 meters, and only that rounded value is transmitted and stored.

Location is used only while the app is in use. The app does not track your location in the background.

No other user can see who wrote a post. Posts are shown only as part of a group ("trend"), never as an individual on a map.

Information Collection and Use

For a better experience, while using our Service, the app handles the following information.

Anonymous user ID

An identifier issued per installation. It contains nothing that identifies you personally. Obtained through Firebase Authentication (anonymous sign-in).

Post content

The word you post (up to 30 characters) and the time of posting. Obtained through your posting action.

Approximate location

Location rounded to about 150 meters. Precise coordinates are never transmitted. Obtained through your posting action, with your permission.

Usage data

Events such as posting and joining, app version, device model and OS version. Location and post text are not included. Obtained through Google Analytics for Firebase.

Anti-abuse data

Information used to verify that the request comes from a genuine device and app. Obtained through Firebase App Check.

Reports

The content reported and the time of the report, when you report a post. Obtained through your reporting action.

The following are kept on your device only and are not collected by me in any way: your language setting, your muted list, your posting history used for cool-down timers, and in-app suggestion state.

Two features process your text entirely on your device, and the text is not sent anywhere for these purposes.

Personal information check before posting. Before a post is sent, the app checks it for phone numbers, email addresses, ID-like strings and similar personal information. On devices that support Apple Intelligence, an on-device language model performs an additional check.

Translation. When you tap the translate button, translation is performed by the translation feature built into your device's operating system (Apple). See Apple's Privacy Policy at https://www.apple.com/legal/privacy/ for details.

The app does use third party services that may collect information used to identify you.

Link to privacy policy of third party service providers used by the app:

Google Analytics for Firebase

https://firebase.google.com/policies/analytics

Firebase Authentication

https://firebase.google.com/support/privacy

Cloud Firestore

https://firebase.google.com/support/privacy

Firebase App Check

https://firebase.google.com/support/privacy

OpenFreeMap (map tiles)

https://openfreemap.org/

The app does not use advertising, does not collect the advertising identifier (IDFA), and does not ask for App Tracking Transparency permission.

Purpose of Use

Information collected is used only for the following purposes:

1. To provide the Service (grouping posts into trends and displaying them on the map)

2. To prevent abuse (rate limiting, handling reports, suspending use)

3. Statistical analysis to improve the Service

Map Display

Map tiles are delivered by OpenFreeMap. When the map is displayed, your device requests tiles directly from OpenFreeMap's servers, and those servers may receive your IP address and the area you are viewing. This request is separate from posting, and the rounded location described above is not attached to it.

Log Data

I want to inform you that whenever you use my Service, in a case of an error in the app I collect data and information (through third party products) on your phone called Log Data. This Log Data may include information such as your device Internet Protocol ("IP") address, device name, operating system version, the configuration of the app when utilizing my Service, the time and date of your use of the Service, and other statistics.

Cookies are files with a small amount of data that are commonly used as anonymous unique identifiers. These are sent to your browser from the websites that you visit and are stored on your device's internal memory.

This Service does not use these "cookies" explicitly. However, the app may use third party code and libraries that use "cookies" to collect information and improve their services. You have the option to either accept or refuse these cookies and know when a cookie is being sent to your device. If you choose to refuse our cookies, you may not be able to use some portions of this Service.

Service Providers

I may employ third-party companies and individuals due to the following reasons:

To facilitate our Service;

To provide the Service on our behalf;

To perform Service-related services; or

To assist us in analyzing how our Service is used.

I want to inform users of this Service that these third parties have access to your Personal Information. The reason is to perform the tasks assigned to them on our behalf. However, they are obligated not to disclose or use the information for any other purpose.

Data collected by the Service is stored on servers operated by Google LLC (Firebase / Google Cloud), including servers located in the Tokyo region.

Retention

Posts and trends are deleted automatically once a trend's lifetime ends. This is typically a few hours to about a day.

Anonymous user IDs and records of reports are retained for the period necessary to prevent abuse.

Your Rights

The Service identifies users only by an anonymous ID, and I have no means of matching that ID to a specific individual. For this reason, I may be unable to respond to requests for disclosure, correction, or deletion that require identifying you as an individual. Deleting the app removes the link between your device and its anonymous ID.

If you have any request regarding the handling of your information, please contact me at the address below.

Security

I value your trust in providing us your Personal Information, thus we are striving to use commercially acceptable means of protecting it. But remember that no method of transmission over the internet, or method of electronic storage is 100% secure and reliable, and I cannot guarantee its absolute security.

Links to Other Sites

This Service may contain links to other sites. If you click on a third-party link, you will be directed to that site. Note that these external sites are not operated by me. Therefore, I strongly advise you to review the Privacy Policy of these websites. I have no control over and assume no responsibility for the content, privacy policies, or practices of any third-party sites or services.

Children's Privacy

These Services do not address anyone under the age of 13. I do not knowingly collect personally identifiable information from children under 13. In the case I discover that a child under 13 has provided me with personal information, I immediately delete this from our servers. If you are a parent or guardian and you are aware that your child has provided us with personal information, please contact me so that I will be able to do necessary actions.

Changes to This Privacy Policy

I may update our Privacy Policy from time to time. Thus, you are advised to review this page periodically for any changes. I will notify you of any changes by posting the new Privacy Policy on this page.

This policy is effective as of 2026-08-02

If you have any questions or suggestions about my Privacy Policy, do not hesitate to get in touch. You can reach the Operator from inside the App (Settings → Contact the Operator), which sends your message directly to the Operator, or through the contact page at https://1023site.wixsite.com/sand/contact.