Privacy Policy

Flippy: AI PDF & EPUB Reader · Effective November 1, 2026

Overview

Flippy is a PDF and EPUB reader for Android, iPhone and iPad, and Mac, and a website at flippypdf.com, with optional read-aloud, AI, and cloud sync features. Your privacy matters to us. This policy explains what data Flippy accesses, how it is used, and your choices. In short: your books stay on your device, there are no ads, we do not sell your data, and the only things that ever leave your device are the specific pieces of text (or reading data) needed to run a feature you chose to use.

Data Stored on Your Device

Flippy stores your library and everything you create locally on your device. This data stays there unless you choose to sign in and turn on Cloud Sync (free and optional; see the next section), and even then only the reading data listed there is uploaded — never your files. The read-aloud and AI features described further down are the other exception: when you use one, the specific text involved is sent away to be processed, as explained in those sections.

Flippy's interface is available in 18 languages. Your language choice is stored on your device and travels with AI requests so that answers come back in your language.

This local data is stored in your device's app storage and is not accessible to us or any third party.

Cloud Sync (optional, free)

Cloud Sync is optional and free for all users — no subscription is required to sign in or sync. Nothing is uploaded until you sign in. If you choose to sign in, the following applies:

The Flippy Website (flippypdf.com)

You can also read in any web browser at flippypdf.com.

Free Week, Free Sample, and Paid Allowances

The read-aloud and AI features below are available with a Premium or Pro subscription, during the free week that starts when you first install the app, from a small free monthly sample, or from a purchased top-up pack. The data handling described in each section is the same in every case. When a free user's sample minutes run out, read-aloud continues in your phone's own built-in voice, which runs entirely on your device and sends nothing anywhere.

AI Read-Aloud

Flippy's natural voices are generated by Kokoro, an open-source voice model, which DeepInfra runs for us, with Together AI running the same model as a second host when DeepInfra is slow or unavailable. Pages in a language Kokoro does not speak yet are read by OpenAI's Text-to-Speech API, which is also the last backup if neither Kokoro host can generate a page.

AI Q&A, Summaries, Explain, Study Tools, and Define

Flippy uses Anthropic's Claude API to answer questions about your books, generate summaries, explain highlighted passages, create study materials (flashcards and quizzes) from chapters you choose, and define words.

Help & FAQ Question Box

Settings → Help & FAQ includes a box where you can type or speak a question about the Flippy app itself. It first searches the built-in FAQ on your device. If you choose "Ask Flippy AI", your question is sent via our backend to Anthropic's Claude API together with a fixed description of the app, so it can answer. None of your books, reading data, or conversation history is sent — the box has no access to them. This is free for everyone and does not count against any allowance; to prevent abuse it is limited to 20 questions per day per install. Spoken questions are transcribed the same way as Ask Aloud (next section). Answers are generated automatically and may be wrong; the written FAQ and our support email are the authoritative sources.

Ask Aloud / Speak-to-PDF Voice Questions

Flippy lets you ask questions out loud — about your book, as a spoken follow-up in Explain or Study, or in the Help & FAQ box. This feature uses your device's microphone.

AI Explain Pictures

When you highlight a word or phrase and tap "Explain," Flippy generates a short, even-handed explanation of that term from the surrounding text (see the AI section above) and, where it helps, shows a picture.

In-App Purchases

Flippy offers optional Premium and Pro subscriptions and one-time top-up packs of extra natural-voice minutes and AI uses. All purchases are processed by Apple (App Store) or Google (Google Play). We never see or store your payment details; billing, receipts, and refunds are handled entirely by the respective store.

Purchases on the Website (Stripe)

Plans and packs bought on flippypdf.com are sold and processed by Stripe as merchant of record, through Stripe's Managed Payments service (receipts may say “Sold through Link”). Stripe collects your payment details, name, email address, and billing address to process the payment, calculate tax, prevent fraud, and send receipts, under the Stripe Privacy Policy and the Link Privacy Policy. We never see your full card details.

Our Backend, Analytics, and Advertising

There are no ads inside Flippy. We do not display ads, sell your data, or include any third-party advertising or analytics SDKs (no Meta/Facebook SDK, no Google Analytics, no crash reporting SDKs).

Flippy uses a small backend service we operate (a Cloudflare Worker) to route read-aloud, AI, transcription, dictionary, and purchase-verification requests to their providers. This proxy lets us keep our API keys server-side so they aren't extractable from the app, and lets us apply usage limits. The backend receives:

The backend does not store the contents of your questions or book pages beyond the lifetime of each request. Per install, it keeps only small operational records: how much of the free monthly sample has been used (kept for about 40 days), how many natural-voice minutes the free week has used (kept for 30 days), a marker that the install recently had an active subscription (kept for 7 days), daily request counts used for rate limiting (kept for one day), the top-up ledger and the subscription records described above, and one small preference — the Reading style you choose for read-aloud (Auto, Natural, Narrator, Lively, or Calm), kept for up to 400 days after you last set it so the voice can follow it — the language of the last page you listened to (kept for one day; see AI Read-Aloud), the test group record described above (kept for 90 days), and the activity markers described in the next paragraph (kept for 90 days). It does not receive bookmarks, highlights, notes, reading history, or any data that identifies you.

The backend also keeps small, anonymous daily counters of certain in-app events so we can understand how Flippy is used, improve the app, and detect abuse of free features. Examples: the app being opened (counted at most once per day per install, so we can see how many devices actively use Flippy), the local hour and weekday when the app is opened (counted, never linked to an install), a book being imported, the upgrade screen being viewed, a purchase or top-up completing, a trial reminder being shown, or a monthly usage limit being reached. Only the name of the event is counted — never the content of your documents, questions, notes, or anything that identifies you — and the counters roll off after 90 days. To count each install only once, the backend keeps small activity markers filed under the install token: one for each event an install sent on a given day (the event name and the date), and one for each day and each month the install was active. They hold nothing else and are deleted after 90 days.

Sharing a Page, Quote, or PDF

When you share a quote card, a page picture, or a PDF from Flippy, the share includes a short line with a link to flippypdf.com/get. The link says only what kind of share it was (for example, a quote card); it contains nothing about you or the book. Whoever taps it is sent to Google Play, the App Store, or the Flippy website, depending on their device. The flippypdf.com/get page sets no cookies and keeps no log or count of who taps it. On Android the Google Play link carries the kind of share as a campaign tag, which Google Play may report to us only as totals.

Notifications

Reading reminders, streak reminders (sent in the evening when your reading streak is about to end), the reminders sent the day before and the day after your free week ends, and — only if you turn on “Remind me before my free week ends” — a reminder three days before it ends, are generated and scheduled entirely on your device using the operating system's local notifications; no push service or server is involved. The name of your last-read book and its page, your reading streak, your monthly listening totals, and the date your free week ends are stored locally to personalize them and never leave your device. To avoid sending reminders you don't need, the app also works out once a day, on your device, how likely you are to come back on your own, from your recent reading and listening activity and your first-launch answers; the result is used only to choose which reminder (if any) to show. Our backend only receives the name of an event for the result (high, medium, or low), counted like the other events above. The playback controls shown in your notification bar while listening are local too. You can turn reminders off anytime in Settings or in your device's notification settings.

Third-Party Services

Flippy integrates with the following third-party services. Except where noted, each is contacted only when you explicitly use the corresponding feature:

Each service is subject to its own privacy policy. Apart from the CDN noted above, no data is shared with these services unless you actively use the corresponding feature.

Children's Privacy

Flippy is not directed at children under the age of 13. We do not knowingly collect personal information from children.

Data Deletion

You can delete all your data at any time:

Changes to This Policy

We may update this privacy policy from time to time. Changes will be posted on this page with an updated effective date.

Contact Us

If you have questions about this privacy policy or your data, contact us at:

flippypdf@gmail.com