Privacy Policy

1. Information We Collect

We collect the minimum information necessary to operate the Service:

• Account information — if you sign in with Google, we receive your name, email address, and profile picture.
• User content — calculator inputs and results you choose to save, and calculators you bookmark as favorites.
• Usage data — pages visited, calculators used, and approximate device/browser information, collected via privacy-conscious analytics.
• Technical data — IP address and request metadata processed transiently by our hosting provider for security and performance.

We do not collect or store passwords. We do not require payment information to use the core Service.

2. Google Authentication Data

SinaumeSync uses Google Sign-In as its only authentication method — we never collect or store passwords. When you sign in with Google, our authentication provider (Supabase Auth) requests the following limited scope of information from your Google Account:

• Your name
• Your email address
• Your Google profile picture (avatar)

This data is used solely to create and identify your SinaumeSync account, personalize the navigation bar, and associate your saved calculations and favorites with your account. We never request access to your Gmail, Google Drive, contacts, or any other Google data beyond basic profile information, and we never post on your behalf or share your Google data with advertisers.

You can revoke SinaumeSync's access to your Google Account at any time from your Google Account permissions page.

3. Payment Information

SinaumeSync is free and does not process payments. We never collect or store card numbers, virtual account, or e-wallet details.

4. AI Assistant Usage Data

If you use the SinaumeSync AI engineering assistant, the questions you submit and the responses generated are processed by our underlying AI model provider to generate a reply. We do not use your conversations to train public AI models, and we do not sell AI usage data. We may retain a limited history of your AI conversations within your account so you can revisit past answers; you can delete this history from your account settings or by requesting account deletion.

5. Cookies & Analytics

We use a small number of cookies and browser storage mechanisms:

• Session storage — to keep you signed in across page loads and browser refreshes.
• Preference storage — to remember interface choices such as recently used calculators.
• Analytics cookies — to understand aggregate usage patterns (e.g., which calculators are most popular) so we can improve the Service. Analytics data is aggregated and not used to build advertising profiles.

You can clear cookies and local storage at any time through your browser settings. Doing so will sign you out and reset any locally stored preferences.

6. Email Communication

We send transactional emails (sign-in confirmations, and replies to your support requests) — these are necessary to operate your account and cannot be opted out of while you hold an active account. We do not currently send marketing newsletters; if we introduce them, you will be able to opt out of marketing email independently of transactional email.

7. How We Use Your Data

We use the information we collect to:

• Authenticate you and maintain your signed-in session
• Save and retrieve your calculations, bookmarks, and favorite calculators
• Provide access to downloadable engineering resources you request
• Operate, maintain, and improve the reliability and performance of the Service
• Communicate with you about your account or material changes to our policies, when necessary
• Detect, prevent, and address technical issues, abuse, or security incidents

We do not sell your personal information, and we do not use your data to serve third-party advertising.

8. Data Retention & Account Deletion

We retain your account information, saved calculations, and favorites for as long as your account remains active. If you delete your account or request deletion, we will remove your personal data and associated saved content from our production database within a reasonable period, except where retention is required to comply with a legal obligation, resolve disputes, or enforce our agreements.

To request deletion, email support@sinaumesync.com from the email address on your account; we will confirm once deletion is complete.

9. Third-Party Services

SinaumeSync relies on the following third-party infrastructure providers to operate the Service:

• Google — provides Google Sign-In (OAuth 2.0) used for authentication. See Google's Privacy Policy.
• Supabase — provides our authentication backend and database (PostgreSQL), where account, saved calculation, and favorites data is stored under row-level security so only you can access your own records. See Supabase's Privacy Policy.
• Vercel — hosts our website and serverless functions and processes standard web request logs for delivery and security purposes. See Vercel's Privacy Policy.
• Google Analytics — provides aggregate usage analytics described in Section 5. See Google's Privacy Policy.

Each provider processes data only to the extent necessary to deliver their service to us and is contractually and/or technically restricted from using your data for their own purposes.

10. Security

We apply industry-standard safeguards to protect your information, including encrypted connections (HTTPS/TLS) for all traffic, OAuth 2.0 / PKCE for authentication (so we never see or store your Google password), and database-level row security so a signed-in user can only read or modify their own saved calculations and favorites. No method of transmission or storage is 100% secure, and we cannot guarantee absolute security, but we work to continuously improve our safeguards.

11. Your Rights

Depending on your jurisdiction, you may have the right to:

• Access the personal data we hold about you
• Request correction of inaccurate data
• Request deletion of your account and associated data
• Export your saved calculations and favorites
• Withdraw consent for optional analytics where applicable
• Object to or restrict certain processing of your data

To exercise any of these rights, contact us using the details below. We will respond within a reasonable timeframe and in accordance with applicable data protection law.

12. Contact Information

If you have questions about this Privacy Policy or how your data is handled, you can reach us at:

We may update this Privacy Policy from time to time. Material changes will be reflected by updating the "Last updated" date at the top of this page.