Privacy Policy

Last updated: October 2026

The sections below describe privacy for the Stemulus app and service, followed by information about this website.

Stemulus is intended for users aged 13 and older.

To request account and data deletion, see Delete your Stemulus account. You can make a request without the app installed.

1. Data Collection

Stemulus processes submitted problem images and text, account identifiers, profile information returned by your sign-in provider, purchase transactions, and usage records. Solutions are saved locally on your device. The service also stores solution text and usage records in Cloudflare storage; successful arithmetic-checked solutions may be cached for up to 30 days.

When the service hits an error, it sends an error report to Sentry (Functional Software, Inc.) so we can find and fix the problem. A report contains the type of request, the address path it was sent to, and the error details. It never contains your problem content, your name, email address, account identifiers or sign-in tokens.

2. Server Result Retention

Our daily cleanup removes server solution and study-result content, cached database copies, and diagnostic solution records older than 30 days. Cleanup may take up to one additional day. Minimal request and purchase records remain for duplicate-charge prevention and account access. Saved solutions on your device remain until you remove them. Provider processing and retention are governed by the providers’ service settings and policies.

3. AI Services

Stemulus asks for your permission before it first sends anything to AI services. After you agree, each time you choose Check Problem, generate a study guide or practice set, or request feedback, the content for that request is sent to this service to produce your result:

• Cloudflare Workers AI (Cloudflare, Inc.), which runs the models that read problems and generate solutions and study results.

For a check, that content is the problem photo or text you reviewed. For study tools and feedback, it is your saved problem text, the saved solution steps, your review marks and your attempts. Your name, email address and account identifiers are not sent to this service. We use this service only to provide Stemulus, and we share data only with providers that protect it at least as well as this policy requires.

You can withdraw this permission at any time in the app under Account & Settings on Android, or Your Account on Apple devices, then Withdraw AI Sharing. Stemulus will then ask again before sending anything. You can delete your account and saved work in the app using Delete Account, or request account and data deletion by email without reinstalling the app.

4. No Third-Party Advertising

We do not track you across apps or sell your data. The app does not include third-party advertising SDKs.

5. Camera & Photos Access

Camera and screen-capture access lets you select a problem. After you choose Check Problem, the selected image and problem text are sent over HTTPS to our service and Cloudflare Workers AI for processing. Capturing an image alone does not submit it.

6. Feedback & Support

If you choose Send Feedback in the app, it sends your message, the category you pick, the email address you optionally enter, and the app and operating system versions to our support system at api.heardkit.com. Messages sent with the form on our support page, or emailed to [email protected], reach the same system. We use them only to answer you and improve Stemulus. Nothing is sent unless you press send.

When reporting an answer, you can also choose to include an answer excerpt. The app shows the message and included excerpt for review before sending.

This website

This marketing website uses Abner, a cookieless analytics tool, to count page visits. It does not set cookies and does not track individuals across sites. The website has no sign-in. Its one form, on the support page, sends what you type (and your email address, if you enter one) to our support system, and uses Cloudflare Turnstile to keep out spam.

Contact

Questions about this policy: [email protected]

Stemulus is operated by Serious Business Software LLC.