Privacy / Edition 1.0
Your notes stay
in your browser.
Backend Drills is an educational practice app. This page describes the data used by the online edition and the services that help run it. Updated October 6, 2026.
Free practice and local progress
The three free drills can be used without an account. Confirmed choices, notes and study-plan checkmarks are stored in your browser's local storage when it is available. The app does not send this learning data to our server and does not sync it between devices.
Signed-in practice uses a separate browser storage key for each account. This prevents accidental mixing in the interface; it does not make notes private from someone who can inspect that browser's storage. Avoid entering confidential production data. Clearing site data or private browsing can remove progress.
Accounts and payments
Clerk handles email verification, account profiles and sessions. Stripe processes checkout, payment details and receipts. Backend Drills does not store full card details or passwords. Cloudflare hosts the application and its access database.
To deliver and recover paid access, the app stores an opaque account identifier, order and Stripe payment references, price, amount, currency, access status and timestamps. Refund and dispute references prevent older payment notifications from restoring revoked access. The app also keeps processed webhook event IDs and short-lived account request counters to handle retries and limit repeated purchase requests.
Retention
Browser learning data remains until you or the browser clears it. Successful purchase and revocation references are kept while they are needed for continuing access and purchase support. Failed checkout attempts and processed webhook IDs are scheduled for deletion after 35 days. Request counters expire after two minutes and are removed during daily cleanup. These are the application's configured policies; each provider retains its own records under its policies.
Hosting and external services
Cloudflare, Clerk and Stripe may process ordinary connection, security and service information under their own practices. Sign-in uses Clerk's session cookies; our protected API uses short-lived bearer tokens, which the app does not save in local storage. External documentation links also have their own privacy practices.
The app does not include advertising scripts, third-party analytics, newsletter collection or AI grading. Shared links may include campaign labels; no custom visitor tracking is configured.
Provider information: Cloudflare, Clerk, and Stripe.
Your controls and questions
Use About this edition to export or clear the current account's browser progress. A progress export can contain your written notes, so keep it private. Automatic import is not included.
For account or payment-data questions, or to request deletion, email support@slicknext.com. We may need to verify account ownership before changing access records. Deleting purchase references can prevent recovery of that access; provider records may remain subject to their own retention requirements. Do not send passwords, verification codes or card details.