Terms of Service

1. Who can use Stackweight

You must be at least 16 years old to use the Service. By using it, you confirm you can form a binding agreement with us and that the information you provide is accurate.

2. Accounts

You are responsible for your account, for keeping your login credentials secure, and for all activity under your account. Authentication is provided through Better Auth. Notify us promptly at [email protected] if you suspect unauthorized use.

3. The Service

Stackweight lets you log body weight, calories, fasting, and related information, organize it into campaigns, and view trends such as weekly averages, change, pace, and projections. Trainers can invite clients and view, create, and edit campaigns on a linked client's behalf.

We may add, change, or remove features over time, including introducing AI-assisted analysis in the future.

4. Plans, billing, and payments

Billing and subscriptions are handled by Polar, our merchant of record. By purchasing a plan you also agree to Polar's applicable terms.

Individual plans.

• Light is a one-time purchase for a single 12-week campaign. It does not renew. When the 12 weeks end, the campaign becomes read-only. You may purchase Light again for a new campaign; prior Light campaigns remain read-only on your account.
• Individual is a recurring subscription (monthly or yearly) providing full client-app access, including the ability to create and continue campaigns and edit your history.

Trainer plans. Starter, Pro, Scale, and Unlimited are recurring subscriptions (monthly or yearly) that allow a trainer to manage up to a stated number of linked clients (5, 25, 100, and no cap, respectively) and include personal tracking for the trainer at no additional client-seat cost.

Renewals and cancellation. Recurring plans renew automatically until cancelled. You can manage or cancel your subscription through the Polar customer portal. Cancellation stops future charges; it does not retroactively refund the current period unless required by law.

Price changes. We may change prices going forward. Changes will not affect the period you have already paid for.

5. Trainer and client relationships

If you are a client who accepts a link to a trainer, you authorize that trainer to view your logged data and to view, create, and edit campaigns on your behalf, for as long as the link is active. You can end this relationship; when a link ends, the trainer loses access going forward.

If you are a trainer, you agree to use client data only for legitimate training purposes, to have the necessary permission from your clients, and to comply with applicable law in handling their information. You are responsible for your conduct toward your clients.

When a trainer's subscription ends, linked clients keep full access through the trainer's paid-through date, then have 30 days of read-only access before needing their own plan to continue.

6. Your content and data

You retain ownership of the data you log. You grant us a limited license to store, process, and display that data solely to operate and provide the Service to you (and, where applicable, to a trainer you have linked with). How we handle personal and health data is described in our Privacy Policy.

7. Acceptable use

You agree not to:

• Use the Service unlawfully or to violate others' rights.
• Access accounts or data that are not yours, or attempt to breach security.
• Interfere with, overload, or disrupt the Service.
• Reverse engineer or resell the Service except as permitted by law.

We may suspend or terminate accounts that violate these Terms.

8. Not medical advice

Stackweight is a tracking and informational tool, not a medical service. The Service, including any trends, projections, or future AI-generated insights, does not constitute medical, nutritional, or professional health advice, and is not a substitute for consultation with a qualified healthcare provider. Do not use Stackweight to diagnose or treat any condition. Always consult a professional before making decisions about diet, weight, fasting, or health. You use the Service and rely on its outputs at your own risk.

9. Third-party services

The Service relies on third parties including Polar (payments), Better Auth (authentication), Resend (email), Railway (hosting), Cloudflare Turnstile (bot protection), and PostHog (analytics), and may use additional providers in the future. We are not responsible for third-party services, and their terms may also apply to you.

10. Disclaimers

The Service is provided "as is" and "as available," without warranties of any kind, express or implied, including merchantability, fitness for a particular purpose, and non-infringement. We do not warrant that the Service will be uninterrupted, error-free, or that data will never be lost. You are responsible for keeping your own records if needed.

11. Limitation of liability

To the maximum extent permitted by law, Aberrant Engineering LLC will not be liable for any indirect, incidental, special, consequential, or punitive damages, or for lost profits, data, or goodwill, arising from or related to your use of the Service. Our total liability for any claim relating to the Service will not exceed the greater of (a) the amount you paid us in the 12 months before the claim, or (b) USD $50.

Some jurisdictions do not allow certain limitations, so some of the above may not apply to you.

12. Indemnification

You agree to indemnify and hold harmless Aberrant Engineering LLC from claims, damages, and expenses (including reasonable legal fees) arising from your misuse of the Service, your violation of these Terms, or — if you are a trainer — your handling of client data.

13. Termination

You may stop using the Service and delete your account at any time. We may suspend or terminate access if you violate these Terms or if we discontinue the Service. Provisions that by their nature should survive (ownership, disclaimers, liability limits, indemnification) survive termination.

14. Changes to these Terms

We may update these Terms as the Service evolves. We will post the updated Terms here and update the "Last updated" date. Material changes will be communicated where required, and continued use after changes take effect means you accept them.

15. Governing law

These Terms are governed by the laws of the State of Illinois, USA, without regard to its conflict-of-laws rules. Disputes will be handled in the state or federal courts located in Illinois, unless applicable law requires otherwise.

16. Contact

Aberrant Engineering LLC
[email protected]