QueryCraft SQL is a free SQL learning product. It includes a public website, a learning app, optional sign-in, progress sync, Daily Challenge tokens, and a contact form.

Account data: if you sign in, we collect your email address and an account identifier so we can authenticate you and connect progress to your account.

Learning progress: we store completed lessons, practice attempts, exam scores, current learning location, streak information, mistakes/review data, Daily Challenge progress, and token totals.

Completion certificates: if a signed-in learner chooses to issue a certificate after passing the final exam, we store the display name they choose, a credential ID, issue date, and completion result. The verification page for that credential is public so employers and profile visitors can verify it; it does not show the learner's email address or account ID.

Contact messages: if you contact us, we collect the email address you provide, the message subject, and the message body so we can respond.

Guest/local data: if you use guest mode, progress may be stored only on the device or browser you are using. Clearing local storage, reinstalling the app, or changing devices can remove guest progress.

We use account and progress data to provide login, save learning progress, calculate scores and tokens, resume your last activity, sync progress, issue and verify an optional completion certificate, troubleshoot issues, and improve lessons and practice flows.

We use contact messages only to read, route, and respond to your request.

QueryCraft may use Supabase for authentication and progress storage, Cloudflare for website hosting and analytics, Resend for contact-form email delivery, Expo and Apple for mobile app builds and distribution, and PayPal for optional website support payments.

These providers process data only as needed to provide their services to QueryCraft.

You can use QueryCraft without an account in guest mode. Signed-in users can delete their account and cloud course data in the app: Settings, Account, Delete account.

If you delete local app/browser data, guest progress may be removed. Signing out keeps cloud progress for a later return; deleting the account permanently removes the account and cloud course data.

QueryCraft is not designed specifically for children under 13. If you believe a child provided personal information without appropriate consent, contact us so we can review and delete it where required.

If we make material changes, we will update this page and its Last updated date.