Privacy Policy

This Privacy Policy explains how BUILD STACK SOLUTIONS LTD ("Fluentist", "we", "us") collects, uses, and protects information when you use the Fluentist mobile application and the website at fluentist.app (together, the "Service").

The short version: Fluentist is a learning app, not a data business. Most of your data — your learning progress, streaks and settings — stays on your device. We don't show ads, we don't use third-party tracking or advertising profiles, and we don't sell your personal information. You can delete your account and data at any time from inside the app.

1. Information we collect

a. Information stored on your device

By design, your learning data is stored locally on your device — not on our servers. This includes your learning progress and review history, experience points (XP), streaks, daily goals, saved words and phrases, badges, and your app settings. If you never create an account, this information generally stays on your device.

b. Account information (only if you sign in)

Creating an account is optional. If you choose to sign in with Google, Apple, or email, we process your name, email address, and a unique user identifier provided by that sign-in method, so we can authenticate you and associate your subscription with your account. We do not receive your Google or Apple password.

c. A device identifier for fair use

When you download language content, the app sends a randomly generated identifier to our content service at api.fluentist.app. We use it only to enforce reasonable download limits and language caps and to prevent abuse of our content delivery. This identifier is not your name, email, or a stable advertising ID.

d. Purchase information

Purchases and subscriptions are processed by the Apple App Store and Google Play — not by us. We do not receive or store your full payment card details. We may receive a purchase receipt or transaction identifier from the store to confirm and restore your entitlements.

e. Diagnostics & crash reports

To keep the app stable, we may collect anonymous crash and error diagnostics (for example, the type of error, device model, and operating system version). Where this is enabled, it is provided by Google's Firebase Crashlytics. These reports are used only to find and fix bugs.

f. What we do not do

• We do not show advertising.
• We do not use third-party advertising or tracking SDKs, and we do not build cross-app or cross-site advertising profiles of you.
• We do not sell or rent your personal information.

2. How we use information

• To provide the core learning experience and save your progress.
• To authenticate you and sync your subscription across your devices (if you sign in).
• To deliver downloadable language content and enforce fair-use limits.
• To process and restore purchases through the app stores.
• To diagnose crashes and improve reliability and performance.
• To respond to your support requests.
• To comply with legal obligations and protect the Service against abuse.

3. Legal bases (EEA/UK users)

Where the UK GDPR or EU GDPR applies, we rely on: performance of a contract (to provide the Service and your purchases); legitimate interests (to secure the Service, prevent abuse, and fix bugs); consent (where required, which you can withdraw); and legal obligation (where the law requires us to retain or disclose information).

4. Sharing & service providers

We do not sell your personal information. We share limited information only with providers that help us run the Service, and only as needed:

• Apple & Google — app distribution, sign-in, and payment/subscription processing.
• Cloudflare — hosting of this website and delivery of language content.
• Google Firebase — authentication (if you sign in) and, where enabled, crash diagnostics.

We may also disclose information if required by law, to enforce our Terms, or to protect the rights, safety, and property of our users or us. If our business is transferred, your information may be part of that transaction, subject to this policy.

5. Data retention

Data stored on your device remains until you delete it, delete your account, or uninstall the app. Account and entitlement records we hold are kept for as long as your account is active and as needed to provide the Service, then deleted or anonymised, except where we must retain them to meet legal, tax, or accounting obligations.

6. Your choices & rights

Delete your account and data. You can delete your account and erase your on-device learning data at any time in the app: Profile → Account → Delete account.

Depending on where you live, you may have the right to access, correct, delete, or export your personal information, to object to or restrict certain processing, and to withdraw consent. If you are in California, you may have rights under the CCPA/CPRA, including the right to know and to delete — and we do not sell or "share" personal information as those terms are defined. To exercise any right, email support@fluentist.app. You also have the right to complain to your local data protection authority.

7. Children's privacy

Fluentist is intended for users aged 13 and over and is not directed to children under 13 (or the minimum age of digital consent in your country). We do not knowingly collect personal information from children under that age. If you believe a child has provided us personal information, contact us and we will delete it.

8. Security

We use reasonable technical and organisational measures to protect information, including encryption in transit. No method of transmission or storage is completely secure, so we cannot guarantee absolute security.

9. International transfers

We and our service providers may process information in countries other than yours. Where we transfer personal information internationally, we take steps to ensure it receives an appropriate level of protection as required by applicable law.

10. Changes to this policy

We may update this policy from time to time. When we do, we will revise the "Last updated" date above and, for material changes, provide a more prominent notice. Your continued use of the Service after an update means you accept the revised policy.

11. Contact us

Questions or requests about privacy? Contact:

BUILD STACK SOLUTIONS LTD (Company No. 17233840)
Registered address: 2 Gold Crest Apartments, 61a Upton Lane, London, England, E7 9FL
Email: support@fluentist.app