Privacy Policy

Who we are

StackCheck is a supplement scheduling and protocol-planning tool. This Privacy Policy explains what information we collect, how we use it, and the choices you have when you use the site.

Information stored on your device

Supplement stack and selected goal - The supplements you enter, your goal selection, dietary preference, and pending checkout state are stored in your browser using localStorage. This lets StackCheck remember your current analysis and restore your results after checkout.

Beta access token - If you are part of a private beta group, an access token may also be stored in your browser so the site can keep your access state between visits.

We do not send this local browser data to our servers as part of the normal analysis flow. You can remove it at any time by clearing your browser storage for StackCheck.

Information you choose to send us

Email address - If you enter your email on the site, we store the email address together with limited context such as your selected goal and supplement count.

Feedback submissions - If you submit product feedback, we store the answers you provide, including whether the analysis felt useful, whether you would have paid for it, your written comments, your goal, dietary preference, supplement count, and the supplement IDs included in that analysis.

Payment confirmation data - When you complete payment through Stripe, we may receive confirmation that payment succeeded and the email address associated with the Stripe checkout session.

Product analytics we collect

We record limited product-usage events to understand how StackCheck is used and where the funnel is working or breaking. These events may include actions such as starting an analysis, seeing the preview, starting checkout, completing checkout, unlocking beta access, capturing an email, or submitting feedback.

These event logs are stored as aggregate counters and mode-based metrics. We do not intentionally attach your name, full supplement stack text, or contact details to analytics events.

What we do not collect

• Your full stack as part of the normal on-site analysis flow
• Medical records, lab results, or healthcare-provider records
• Payment card numbers or full payment credentials
• Browser fingerprinting data for advertising purposes
• Personal data purchased from data brokers

How we use your data

• To operate the site and restore your analysis locally in your browser
• To process and confirm payments through Stripe
• To store and review feedback you choose to send us
• To manage optional email capture and related product communications
• To understand aggregate usage patterns and improve the product
• To prevent abuse, debug issues, and maintain service reliability

We do not sell your personal information or share it with third parties for their own advertising or marketing.

Third-party services and processors

Stripe - We use Stripe to process payments. When you leave StackCheck for checkout, Stripe handles the payment transaction under Stripe's own privacy terms. We may receive payment status and the email tied to the checkout session.

Hosting and infrastructure providers - StackCheck is hosted using third-party infrastructure providers that may process request metadata such as IP address, timestamps, and technical logs for security, delivery, and uptime purposes.

Cloud data storage - Emails, analytics counters, payment confirmations, and submitted feedback may be stored using our hosted key-value data infrastructure.

Data retention

Local browser data remains on your device until you clear it.

Emails, feedback submissions, and payment-confirmation records may be retained until they are no longer needed for product operations, support, analytics, or legal/compliance purposes, or until you ask us to delete them where applicable.

Usage-event counters may be retained for historical analytics and product-performance reporting.

Your choices and rights

You can avoid sending personal information to us by using StackCheck without entering an email address and without submitting feedback.

You can clear browser-stored stack data at any time by clearing your site storage.

You may request access to, correction of, or deletion of personal information we hold about you by contacting us through the feedback form. Please include enough detail for us to locate your record, such as the email address you used.

Cookies and similar technologies

StackCheck uses your browser's localStorage to remember your stack, goal, dietary preference, beta access token, and pending checkout state. This is similar in function to a cookie but stays on your device. We do not use cookies or localStorage for cross-site advertising or third-party tracking. Hosted analytics and infrastructure providers may set small technical identifiers as part of their own operation. Because we do not track you across other sites, Do Not Track browser signals do not change how we handle your data.

European Economic Area, UK, and Swiss residents

If you are in the European Economic Area, the United Kingdom, or Switzerland, the General Data Protection Regulation (GDPR) or equivalent local law may apply. In that case you may have the right to access the personal data we hold about you, correct inaccurate data, request deletion, object to or restrict certain processing, receive a copy of your data in a portable format, and withdraw any consent you previously gave. You also have the right to lodge a complaint with your local data protection authority. To exercise any of these rights, contact us through the feedback form.

Our legal bases for processing personal data under GDPR include performance of our agreement with you (such as delivering paid access), your consent (such as when you choose to submit feedback or an email address), and our legitimate interests in operating, securing, and improving the service.

California residents (CCPA / CPRA)

If you are a California resident, the California Consumer Privacy Act, as amended by the California Privacy Rights Act, may apply. You may have the right to know what personal information we collect and how we use it, request a copy of that information, request correction or deletion, and limit the use of sensitive personal information. We do not sell your personal information and we do not share it with third parties for cross-context behavioral advertising. To exercise any of these rights, contact us through the feedback form. We will not discriminate against you for exercising a privacy right.

International users

If you use StackCheck from outside the country where our services are operated, your information may be processed and stored in other countries where our service providers operate infrastructure. By using the service, you understand that your information may be transferred to and processed in those countries.

Children's privacy

StackCheck is not intended for children under 13, and we do not knowingly collect personal information from children.

Changes to this policy

We may update this Privacy Policy from time to time. If we do, we will update the "Last updated" date on this page. Your continued use of StackCheck after an update means you accept the revised policy.

Contact

If you have a privacy question or want to make a request about your information, use the feedback form and include enough detail for us to understand the request.