Privacy

Overview

Quantary is an independent project. We collect only what's needed to provide the service and improve it. We don't sell your data, serve ads, or use tracking pixels.

For privacy inquiries, contact privacy@quantary.dev.

What we collect

Account information

If you create an account, your email address and authentication method (e.g. Google, GitHub, or email/password) are stored by our authentication provider. This is used solely to identify you and manage your session.

Challenge progress

If you're signed in, your challenge completion progress is stored on our servers so it persists across devices. If you're not signed in, progress is stored in your browser's localStorage and never leaves your device.

Payments

If you subscribe, payment processing is handled by a third-party payment processor. We store your subscription status and billing period — not your card number or full payment details. The payment processor may collect your email, billing address, and card information as needed to process the transaction and calculate applicable taxes.

Email updates

If you subscribe to launch updates, your email address is stored by our newsletter provider. Every email includes an unsubscribe link.

Analytics and advertising

We use analytics tools to understand how visitors use the site (pages visited, general usage patterns). We may also use advertising pixels from platforms where we run campaigns to measure ad effectiveness. These tools may set cookies in your browser. They collect anonymous usage data — not personal information like your name or email. You can block these via your browser's cookie settings or an ad blocker.

Feedback

If you submit the optional feedback form after completing a module, we store your rating, difficulty selection, and any comment you provide. We also record a hashed IP address (for rate limiting) and device type.

How we use it

Account and progress data: to provide the service and let you resume where you left off. Payment data: to manage your subscription and comply with tax obligations. Email: to send updates you opted into. Feedback: to improve module quality and difficulty calibration.

Third-party services

We use third-party providers for authentication, payment processing, data storage, email delivery, rate limiting, and hosting. These providers process data on our behalf and are bound by their own privacy policies. Data may be processed in regions outside the EEA, relying on Standard Contractual Clauses (SCCs) as the transfer safeguard where applicable.

Retention

Feedback records are automatically deleted after 24 months. Rate-limiting data expires within 1 hour. Account and progress data are retained as long as your account exists. Subscription records are retained as required for tax and legal compliance.

Your rights

You can unsubscribe from email updates at any time using the link in any email. You can request access to, correction of, or deletion of your personal data. If you're in the EEA, you also have the right to object to processing based on legitimate interest and to lodge a complaint with your local data protection authority. Contact privacy@quantary.dev to exercise any of these rights.

Browser storage

We use localStorage to store challenge progress (for users not signed in) and optional form preferences. This data never leaves your device. You can clear it at any time via your browser settings.

Changes

We may update this policy as the service evolves. Significant changes will be noted by updating the date at the top of this page.