This policy explains what personal information Euler Tech Co., Limited collects when you use our apps, websites, and services, how we use it, who we share it with, and the choices you have. It is written in plain language on purpose.
Euler Tech Co., Limited ("Euler Tech", "we", "us", "our") is a private company limited by shares incorporated in the Hong Kong Special Administrative Region, with its registered office at Flat 3305, 33/F, Tower 1, Lippo Centre, 89 Queensway, Admiralty, Hong Kong.
This Privacy Policy applies to personal information collected through our website at eulercore.com, our mobile applications distributed through the Apple App Store and Google Play, and our browser‑based products. Where one of our products has additional privacy notices specific to that product, those notices sit alongside this policy and are linked from the product's support page.
We comply with the Personal Data (Privacy) Ordinance (Cap. 486) of Hong Kong. Where users are located in jurisdictions with additional requirements — including the European Union and the United Kingdom (GDPR and UK GDPR), Singapore (PDPA), mainland China (PIPL), and the United States (including the CCPA/CPRA for California residents) — we apply those requirements to residents of those jurisdictions.
We process personal information for the following purposes:
Where the GDPR, UK GDPR, or comparable laws apply, we rely on the following legal bases: (a) performance of a contract with you, when you use an app or purchase a subscription; (b) our legitimate interests in operating, securing, and improving our products, where those interests are not overridden by your rights; (c) your consent, for example when you accept tracking through Apple's App Tracking Transparency dialogue; and (d) compliance with legal obligations.
Some of our apps are free and supported by third‑party advertising. In those apps, a software development kit ("SDK") provided by an advertising network runs on your device and requests advertisements to display. These SDKs typically receive some or all of the following information:
Advertising networks use this information to choose which ad to show you, to prevent fraud, and to measure campaign performance. Where you have not consented to tracking, we request that our advertising partners serve non‑personalised ads only, and we configure our SDK integrations accordingly.
We also use privacy‑respecting analytics to measure how our products are used. Where possible we use tools that do not rely on persistent identifiers and do not track you across other services. When a cookie or identifier is used, the retention period and purpose are listed in our Cookie Policy.
Payments for digital content within our apps are processed by Apple (for iOS and iPadOS) and Google (for Android). We do not receive your payment card details; Apple or Google tells us only that a purchase was completed.
Subscriptions renew automatically at the end of each period unless cancelled at least 24 hours before the renewal date. You can cancel at any time through your Apple ID or Google Play account. Refund requests are processed by Apple or Google according to their published policies — see our Refund Policy for details.
Our apps may include the following third‑party SDKs. Each provider has its own privacy policy, linked below. The specific SDKs used in a given app are listed in that app's "About" screen.
| Provider | Purpose | Privacy policy |
|---|---|---|
| Google AdMob | Serving and measuring advertisements in free apps | policies.google.com/privacy |
| Meta Audience Network | Serving and measuring advertisements in free apps | facebook.com/policy.php |
| AppLovin / MAX | Mediation and measurement of advertising across networks | applovin.com/privacy |
| Google Firebase (Crashlytics, Analytics) | Crash reporting and aggregate usage analytics | firebase.google.com/support/privacy |
| Apple StoreKit | Processing purchases on iOS and iPadOS | apple.com/legal/privacy |
| Google Play Billing | Processing purchases on Android | policies.google.com/privacy |
On iOS, before any of our ad‑supported apps requests permission to access the advertising identifier or to track you across other companies' apps and websites, iOS will present the App Tracking Transparency dialogue. If you choose "Ask App Not to Track", we instruct our advertising partners to serve non‑personalised ads only and we do not share the identifier.
You can change this choice at any time in Settings → Privacy & Security → Tracking. You can also turn off personalised ads globally in Settings → Privacy & Security → Apple Advertising.
We do not sell personal information. We share it only in the following circumstances:
We keep personal information only for as long as necessary for the purposes set out in this policy and to meet our legal obligations. Typical retention periods are:
Our primary infrastructure runs in Hong Kong and Singapore. Some service providers process data in the United States, the European Union, and other jurisdictions. Where personal information is transferred across borders, we rely on contractual safeguards such as Standard Contractual Clauses where required, or the data subject's informed consent.
We maintain reasonable administrative, technical, and physical safeguards to protect personal information. These include encryption of data in transit (TLS 1.2 or higher) and at rest (AES‑256), least‑privilege access controls, mandatory multi‑factor authentication for staff, regular backups, and a documented incident response procedure. No system is completely secure, and we cannot guarantee absolute security; we will notify you of a personal data breach affecting you where required by applicable law.
Subject to applicable law, you have the right to:
To exercise any of these rights, write to [email protected]. We will respond within 30 days, and may need to verify your identity before acting on the request.
Our apps and services are directed at general audiences and are not designed for children under the age of 13 (or the equivalent minimum age in your jurisdiction). We do not knowingly collect personal information from children. Where we operate an ad‑supported app, we configure our advertising partners to exclude personalised advertising for signals that indicate a child user, in line with the Children's Online Privacy Protection Act in the United States and comparable laws elsewhere. If you are a parent or guardian and believe your child has provided personal information to one of our apps, write to [email protected] and we will remove it.
If you are a California resident, the California Consumer Privacy Act, as amended by the CPRA, gives you additional rights, including the right to know, the right to delete, the right to correct, and the right to opt out of "sale" or "sharing" of personal information for cross‑context behavioural advertising. We do not sell personal information for money. Where you have not consented to tracking, we do not share personal information for cross‑context behavioural advertising. To exercise your rights, write to [email protected]. We do not discriminate against users who exercise their privacy rights.
Most of our apps do not require an account. For apps that do, you can delete your account and associated data directly in the app under Settings → Account → Delete account, or by writing to [email protected] from the email address on the account. Deletion is completed within 30 days, subject to limited retention required by law (for example, purchase records for tax purposes). Further detail is on our support page.
We may update this policy from time to time. The "Last updated" date at the top of the page will reflect any change. For material changes, we will give reasonable advance notice through the apps, our website, or by email to account holders.
Euler Tech Co., Limited
Flat 3305, 33/F, Tower 1, Lippo Centre
89 Queensway, Admiralty
Hong Kong SAR
Privacy enquiries: [email protected]
General enquiries: [email protected]
Telephone: +852 5579 5822