Privacy Policy

Last updated: July 27, 2026

This policy explains how we collect, use, and protect your data.

1. Information We Collect

Information You Provide

  • Account information: Email address, name, and password when you create an account.
  • Child details: Name, age, description, interests, and other details you provide to personalize stories. This information is used solely for story generation.
  • Photos you upload: Where you choose to upload a photo of a child (or other person) to personalize illustrations, that image is used solely as a visual reference to generate the artwork for your book. To create the illustrations, the photo is sent to the third-party AI providers named in Section 3, who process it as our processors under their own data-processing terms. We never sell your photos, and we do not use uploaded photos for any purpose other than generating your book. We keep an uploaded photo only so you can regenerate illustrations or order a reprint later; you can request deletion of any uploaded photo at any time by emailing info@booku.design, and we will delete it within a reasonable period.
  • Payment information: Processed securely through Stripe. We do not store your credit card details.

Information Collected Automatically

  • Usage data: Pages visited, features used, and interaction patterns. We use PostHog (see Section 3) to understand how the site is used — for example how many people reach a finished preview, and where people get stuck.
  • Device information: Browser type, operating system, and device identifiers.
  • Cookies: We use essential cookies for authentication, session management, and security (including bot protection). These are required for the site to work and are always active.

We also use analytics and advertising cookies — PostHog, to measure how the site is used, and the Meta (Facebook) pixel, to measure whether our ads bring people who go on to make a book. These are only set if you accept them when you first visit — we ask before anything non-essential is stored on your device, and if you decline, nothing is. You can change your mind at any time using the Cookie settings link in the footer, and withdrawing consent stops them immediately.

We do not record your screen or session, and we do not sell any of this data.

2. How We Use Your Information

  • To generate personalized stories and illustrations.
  • To process payments and deliver purchased content.
  • To improve our service and user experience.
  • To communicate with you about your account and purchases.
  • To comply with legal obligations.

3. Data Sharing

We do not sell your personal data. We share your information only with the following third-party providers, who act as our processors under their own data-processing terms, strictly for service delivery:

  • Google — Gemini (via the Gemini API and Vertex AI), Google Cloud Vision, and Firebase / Google Cloud — Google is our main AI provider and receives the child details you provide (name, age, description, interests) and the photos you upload. Photos are used to generate the illustrations, to describe the person's appearance so the artwork is consistent, and — through Google Cloud Vision — to check an uploaded photo automatically for unsafe content and image quality before we accept it. Google Cloud also stores your account, book, and photo data and hosts the website. We use Google's paid AI services, under which Google does not use your prompts or the generated results to improve its own products, and processes them as our data processor under Google's Data Processing Addendum. May be processed on servers outside the European Economic Area (EEA), such as in the United States — see Section 4a.
  • OpenAI — An additional AI provider, used for certain illustration styles, for some story and editorial text, and for automated quality checks on generated images. Receives the child details and photos needed for those steps, under OpenAI's data-processing terms; may be processed in the United States — see Section 4a.
  • Anthropic — Used to write and edit the story text. Receives text only — the child's first name, age, gender, interests, and anything you type in the personalization field — together with the story being written. It does not receive any photograph. Anthropic processes this as our data processor and does not use it to train its models. Because of the model we use, these prompts are retained by Anthropic for a limited period (at least 30 days) before deletion. May be processed in the United States — see Section 4a.
  • Claid.ai — For printed (hardcover) orders only. Receives the finished illustrations from your book in order to increase their resolution for print. It does not receive the photos you uploaded.
  • PostHog — Product analytics, hosted in the European Union. Only used if you accept analytics cookies. Receives usage events (pages viewed, features used, whether a preview completed), your email address if you have an account, and your device and browser information. It does not receive uploaded photos, and we have disabled session recording. See Section 1.
  • Meta (Facebook and Instagram) — Advertising measurement. Only used if you accept analytics and advertising cookies. If you arrive from one of our ads, Meta receives the fact that you viewed a page, started a book, or completed a purchase, along with the purchase amount, so we can tell which ads actually work. Where we send this from our server, any email address is hashed before it leaves us — Meta never receives it in readable form. Meta does not receive uploaded photos, the child's details, or the story text. Processed in the United States — see Section 4a.
  • Stripe — Processes payment transactions, and for hardcover orders collects your delivery address and phone number. We do not store your card details. No information about the child is sent to Stripe. Subject to Stripe's privacy policy.
  • Resend — Sends transactional emails (order confirmations, your finished book, reminders). Receives your email address, the relevant order details, the child's first name, and a link to your book's cover illustration so it can be shown in the email.
  • Lulu — For printed (hardcover) orders only. We provide your name, shipping address, and the finished book file to our print partner so your book can be printed and shipped. This step is carried out by a member of our team rather than automatically.

4. Children's Privacy

Booku is a service for parents and guardians to create content for children. We do not knowingly collect information directly from children under 13. All child-related information is provided by the parent or guardian.

4a. International Data Transfers

We are based in the European Union. Some of our processors — in particular the AI providers (Google, OpenAI, and Anthropic) we use to generate stories and illustrations, and our hosting provider — may process the data you provide (including child details and any uploaded photos) on servers located outside the European Economic Area (EEA), such as in the United States. Where this happens, we rely on the data-transfer safeguards and data-processing terms that these providers make available, which they offer to support compliance with the EU General Data Protection Regulation (GDPR). You can find details in each provider's own privacy and data-processing terms (Google Cloud, OpenAI, Anthropic), and you can ask us for more information — including which providers are involved — by contacting us at info@booku.design.

5. Data Retention

We keep your account, your books, and any photos you uploaded for as long as you keep them, so that you can re-download, regenerate, or reprint your book. If you have an account, you can delete an individual book — or permanently delete your entire account and all its data (books, uploaded photos, and order history) — yourself at any time from your library. You can also ask us to delete your data by contacting us at info@booku.design, and we will delete it within a reasonable period. After deletion, copies may persist for a short time in routine backups before being overwritten.

6. Your Rights

Depending on your location, you may have the right to:

  • Access the personal data we hold about you.
  • Request correction of inaccurate data.
  • Request deletion of your data.
  • Object to or restrict processing of your data.
  • Data portability.
  • Withdraw consent to marketing emails.

To exercise any of these rights, contact us at info@booku.design, and we will respond within a reasonable period. Registered users can also permanently delete individual books or their entire account — including all uploaded photos and order history — directly from their library at any time.

7. Security

We implement appropriate technical and organizational measures to protect your data, including encryption in transit and at rest, access controls, and regular security reviews.

8. Changes to This Policy

We may update this privacy policy from time to time. We will notify you of significant changes via email or through a notice on our website.

9. Contact

For privacy-related questions or requests, contact us at info@booku.design.

Mind Technologies s.r.o.

Rixdorfská 2924/6, 130 00 Praha 3, Czech Republic

IČO: 22042024

Registered at the Municipal Court in Prague, file C 410100

info@booku.design