Privacy Policy

1. Browser-Only Architecture & Zero Accounts

KDP Toolkit operates as a free, client-side Production & Profit Sheet. It does not require user registration, account sign-in, passwords, or payment credentials.

• No server-side sheet storage: We do not store your entered manuscript specifications, trim dimensions, page counts, royalties, list prices, or advertising assumptions on our servers.
• Fresh sessions on refresh: An ordinary page refresh opens an empty worksheet. A URL containing a share fragment can restore the inputs encoded in that link.
• Local execution: Royalty formulas, spine width measurements, printing cost computations, baseline comparisons, plain-text exports, and print formatting run locally within your device's JavaScript engine.
• No manuscript access: We never request, receive, process, or store book interior files, manuscript text, or full cover art.

2. Book Inputs & Share Links (#sheet=)

While working in the tool, inputs stay in your browser unless you choose to copy and share them in a link.

If you intentionally choose to click Copy share link, the tool serializes your current specifications and pricing inputs into the URL fragment identifier (the portion following #sheet=).

3. Network Delivery & Cloudflare Workers

This website is hosted and distributed globally via Cloudflare Workers. When you load the site, Cloudflare receives standard network transmission metadata necessary to deliver files and protect the infrastructure against denial-of-service (DDoS) attacks and malicious traffic.

This metadata may include IP addresses, request headers, browser user agents, and request timestamps. For full details on Cloudflare's data processing practices, please consult the Cloudflare Privacy Policy.

4. Anonymous Usage Analytics (Self-Hosted Umami)

To understand site usage and improve the worksheet, this preview deployment uses self-hosted Umami Analytics. It records the following limited information:

• Visits and actions: Umami records page views and anonymous events for the first manual edit, the first valid result, exports, print requests, and safe error categories. Individual events are stored before they are summarized in reports.
• Zero book inputs: Interaction events never include book titles, trim dimensions, page counts, dollar amounts, share fragments, or freeform text.
• Fragment and search exclusion: The analytics script runs with both data-exclude-hash="true" and data-exclude-search="true" enabled, ensuring URL hashes (including #sheet= data) and query parameters are stripped before telemetry is sent.
• No analytics cookies or named profiles: Umami does not use cookies, and this site does not call its identify function. Actions can still be grouped within an anonymous visit.
• Session generation: Umami derives an anonymous, rotating session hash based on your IP address and User-Agent string. For implementation details, refer to Umami Sessions, the Umami FAQ, and Umami Metric Definitions.

5. Data Retention & User Requests

Self-hosted Umami database records are retained until deleted by the site administrator; there is currently no automated 30-day or 90-day rolling purge policy.

Events are not linked to an account or name. We may not be able to reliably identify one visitor's events for an individual deletion request. Contact us below with privacy questions or requests.

The worksheet has no account data or server-side sheet records to delete. It does not offer an in-app data deletion control.

6. External Links & Amazon KDP Non-Affiliation

This website provides informational outbound links to official Amazon Kindle Direct Publishing (KDP) help documentation, official calculators, and pricing matrices.

If you follow an external link, that site applies its own privacy practices and terms. KDP Toolkit is an independent project and is not affiliated with, operated by, sponsored by, or endorsed by Amazon.com, Inc. or Kindle Direct Publishing.

7. Contact & Updates

If you have questions, corrections, or inquiries regarding this Privacy Policy or the tool's technical data handling, you may reach the administrator via email at:

This policy was last reviewed and updated on September 24, 2026.