Privacy Policy
Last updated: August 31, 2026
1. Introduction
BookHalo (the "Service") is a Chrome extension that transcribes pages into personal reading-note text and a reference PDF from pages visible in Kindle Cloud Reader. This policy explains how the Service handles data.
2. Information we handle
- Page images and transcribed text: The extension captures pages visible in Kindle Cloud Reader and uses them to produce the transcribed text and the ZIP. Supported languages are Japanese, English, Portuguese, Spanish, French, German, and Italian.
- Book metadata: ASIN, title, page or location, progress, selected book language, and other information displayed by Kindle Cloud Reader.
- Account information: Your email address and authentication state. We use the address for registration and authentication, one follow-up after a completed use, and support replies.
- Payment information: Payments are processed by Stripe. BookHalo does not directly store credit-card numbers.
- Processing records and diagnostics: Page positions, image hashes, character counts, processing duration, job status, browser and book metadata, and error details used for quota management, integrity checks, reliability, and support. The completed ZIP containing the transcribed text and the reference PDF is kept on your device.
- Export ID in output files: The generated PDF and text files carry an identifier for that job (the Export ID). It is not anonymous: matched against our records, it leads back to the account. We use it only to investigate a report of unauthorized redistribution. While the output stays on your device, we do not hold its contents.
- Website analytics: When you visit book-halo.com, we may record the page path, referring page, acquisition parameters (
src,medium, andcampaign), browser language, country or region, and a hash of the User-Agent. We do not store the raw IP address in the analytics database.
3. Purposes
- Transcribe pages and create downloadable reading-note files.
- Verify capture integrity (detect duplicate or missing pages).
- Authenticate users, manage subscriptions, and enforce usage limits.
- Send authentication codes, a one-time review request after a completed use, and support replies.
- Investigate errors, improve reliability, and provide support.
- Measure website usage and acquisition sources.
4. Recipients and processors
We use the following processors. Each processes data only on our instructions and not for its own purposes.
- Cloudflare, Inc. (United States) — application hosting, database, file storage, and website delivery.
api.book-halo.comreceives account, usage, processing, diagnostic, and website-analytics data over HTTPS. - Stripe, Inc. (United States and Ireland) — payment processing. Card details are not stored by BookHalo.
- Resend (United States) — email delivery. It processes the recipient address and message content needed to deliver authentication codes, the one-time review request, and support replies.
- Discord Inc. (United States) — operational alerts for the operator. Account, billing, and cancellation alerts include the email address. Alerts about a job carry no book title: only a partial internal user identifier and the book's ASIN.
Where personal data is transferred from the EEA or the UK to the United States, the transfer relies on appropriate safeguards such as the Standard Contractual Clauses.
5. Retention
| Data | Where | Retained for |
|---|---|---|
| Page images, transcribed text, completed ZIP | Your device only | 7 days after the last update (you can delete it any time from the extension) |
| Book metadata and processing records (ASIN, title, page positions, hashes) | Our database | 180 days, after which information identifying the book (ASIN, title) is erased and only the records needed for quota accounting remain |
| Error and diagnostic records | Our database | 90 days. They do not include book titles |
| Contact messages and the reply-to email address | Our database | 1 year |
| Website analytics | Our database | 180 days |
| Account information (email address, subscription state) | Our database | Until you delete your account |
| Transaction records | Stripe | As required by law |
| Authentication token | Your browser | Until you log out |
6. Legal bases (for users in the EEA and the UK)
- Performance of a contract (GDPR Art. 6(1)(b)) — providing transcription, authenticating your account, billing, and sending authentication codes.
- Legitimate interests (Art. 6(1)(f)) — investigating faults, preventing abuse, keeping the service reliable, understanding usage, and the single follow-up after a completed use. We limit this to what is necessary and balance it against your rights.
- Legal obligation (Art. 6(1)(c)) — retaining transaction records required by law.
7. Sharing
We do not sell personal data. We share it only with service providers needed to operate the Service, such as Stripe, Cloudflare, Resend, and Discord, or when disclosure is required by law.
8. Browser access and permissions
The extension runs content scripts only on supported Kindle Cloud Reader / Kindle for Web domains. It uses activeTab for visible-tab capture, scripting for Kindle-page interaction, storage for authentication state, downloads to save completed ZIPs through Chrome's standard download manager and observe completion, offscreen to transcribe, build the reference PDF, TXT, and ZIP, and delete working data without disrupting the visible Kindle page, and host permissions for supported Kindle and BookHalo server domains.
9. Your rights
You can exercise the following rights over your personal data by contacting us at the address below.
- Access — obtain a copy of the data we hold about you
- Rectification and erasure
- Restriction of processing
- Objection to processing based on legitimate interests
- Data portability — receive your data in a machine-readable format
- Withdraw consent at any time, where processing is based on consent
If you are in the EEA or the UK, you also have the right to lodge a complaint with your local data protection authority.
10. Account deletion
Cancelling your subscription and deleting your account are two different things. To cancel only, use the “Manage plan / cancel” button in the extension popup, or the billing page. To remove your account entirely, use the Delete account command in the extension popup. Deleting it removes all data linked to you: account information, processing records, error and diagnostic records, acquisition records, and any completed ZIP held in private cloud storage. If you have an active subscription, deletion happens once the cancellation completes.
11. Contact
Use the contact form — you do not need to be a BookHalo user. You can also email contact@book-halo.com.
12. Changes
We may update this policy. Material changes will be reflected on this page with a revised update date.