Privacy — FilePrepLab KDP Size Companion

Last updated: 14 October 2026

This policy describes the FilePrepLab KDP Size Companion Chrome extension. FilePrepLab website visits are covered separately by the website privacy policy.

Information used on your device

The extension uses three settings you type into its own interface: manuscript page count, trim size, and ink/paper combination. It calculates paperback spine and full cover dimensions locally. It does not ask for a book title, ISBN, Amazon login, email address, manuscript, or cover file.

If you turn on Remember settings on this device, those three settings are saved in Chrome extension local storage. They are not synced or transmitted to FilePrepLab. Invalid settings are not saved. Turn remembering off or select Reset to remove the extension's saved settings. They otherwise remain until you clear the extension's data or remove it through Chrome.

After you click the extension's sidebar button, it checks the active tab's URL to confirm the exact https://kdp.amazon.com origin. The URL is used temporarily for this check. It is not saved, logged, or transmitted. This is a current-tab check, not a browsing-history record.

KDP companion panel

A content-script listener is limited to the top-level pages matching https://kdp.amazon.com/*. After installation with the relevant site access, the listener loads on those pages. It adds the companion panel only when you click Open KDP sidebar in the extension. Closing the panel removes the extension's own elements.

The extension does not read Amazon form values, uploaded files, account details, private messages, or page text. It does not detect actual rejection errors, change Amazon form fields, upload files, or submit publishing actions. Manual book settings entered in the popup may be passed locally to the extension's own panel so that you can continue the same calculation.

Permissions

• activeTab: checks the current tab's URL after your action to limit the sidebar to the intended KDP origin.
• storage: saves the three manual book settings locally only when you opt in, and deletes them when you turn remembering off or reset.
• KDP-only content-script access: receives messages from this extension and displays its own manual calculator panel on the exact HTTPS KDP host. No other website is matched.

Transmission, sharing, and limited use

The extension does not send your book settings or current-tab URL to FilePrepLab or another server. It has no analytics, advertising, account system, cloud sync, remote executable code, or background network fetch. User information is not sold or shared for advertising, credit decisions, or purposes unrelated to the sizing companion. The extension uses its permissions only to provide the described sizing and manual-panel features, consistent with the Chrome Web Store User Data Policy and Limited Use requirements.

External links open only when you choose them. Opening FilePrepLab's web calculator, PNG reference exporter, 150-page PSD working files, or Amazon's official help requires the internet. The destination website may process ordinary web requests under its own privacy policy. Book settings are not automatically included in those links; review and enter the correct settings on the website before exporting.

Your choices and contact

Remembering settings is off by default. You can reset saved settings, restrict or revoke the extension's KDP site access through Chrome, disable the extension, or remove it. Revoking site access prevents the KDP panel from opening; the offline popup calculator remains available.

Questions: support@filepreplab.com.