1. Who we are and what this covers
Chartle is a mobile application published by Buffalo Dijital Hizmetler A.Ş. ("Buffalo", "we", "us"), a company incorporated in Türkiye. This policy explains what we collect when you use Chartle, why we collect it, who we share it with, and what you can ask us to do about it.
It applies to the Chartle mobile application and to chartleapp.com. It does not apply to the App Store, Google Play, or any other service you reach from Chartle, each of which has its own policy.
For the purposes of the Turkish Personal Data Protection Law No. 6698 ("KVKK") we act as the data controller. Where the EU General Data Protection Regulation ("GDPR") applies to you, we act as controller within the meaning of that regulation.
Contact: chartle@buffalostudio.co
Address: Cevizli Mah. Zuhal Cad. A Blok No: 46/50, 34846 Maltepe / İstanbul, Türkiye
2. What Chartle does not ask for
It is easier to describe Chartle by what it leaves out.
The Chartle mobile app has no user login. There is no sign-up, password, email-address requirement or social login. The optional website waitlist is described separately below. We do not ask for your phone number, your date of birth, or any financial account.
Chartle does not access your camera, photo library, microphone, contacts, calendar, health data, or precise location. It holds no brokerage connection and cannot see any portfolio, trade or balance, because it never asks for one. The charts inside the app are historical market data we ship with it, not anything of yours.
Your profile is a private progress screen. There is no chat, public profile, comment section or way for one user to see another user’s name or progress. Buffalo and the service providers described below process data to operate the app.
3. What we collect
3.1 What you tell us
During onboarding, Chartle asks for a first name or nickname, chart experience, preferred topics, learning goals, weekly pace and self-rated confidence. It also records your answer to the introductory chart question. You can change your pace later and complete a confidence check-in after 30 days.
Your name is used to address you inside the app and is not shown to other users. Onboarding answers, including the name, are saved locally and sent to our Firestore database so they can be restored when the device can be recognised. They are accessible to authorised Buffalo personnel and our infrastructure provider. The current app does not send the name as an analytics or advertising profile property. Earlier versions may have sent a name property to Firebase Analytics and Mixpanel; updating the app does not itself erase previously collected data.
3.2 What the app records as you use it
Chartle records patterns encountered, correct and incorrect answers, skipped questions, recognition and direction-reading results, practice days, streaks, experience points and recent session history. Core progress is saved on the device and mirrored to Firestore under a device-linked identifier.
Sequential lesson completion, lesson checkpoints, unfinished daily and introductory sessions, daily accuracy comparisons and confidence check-ins are currently saved locally. The learning curriculum is shared by users; completion unlocks later lessons. The app uses practice results to offer revision, without creating an individually generated curriculum. “Saved locally” describes the full records used to resume or display those features; it does not mean that no related usage events leave the device. For example, lesson-completion events include a pattern and unit identifier, pace-change events include the selected weekly goal, and confidence-check events include the selected confidence rating. These events are sent to Firebase Analytics and Mixpanel as described in sections 3.4 and 5.
3.3 Identifiers
Chartle uses a device-linked identifier: Apple's identifier for vendor (IDFV) on iOS or ANDROID_ID on Android, with a random identifier as a fallback. It caches this in secure device storage. This identifier may survive deleting and reinstalling the app. Its availability depends on the platform and device state, so restoration is not guaranteed. Firebase Authentication also creates an anonymous authentication session. These identifiers are associated with onboarding answers and progress; they are pseudonymous identifiers, not a claim that the associated data is anonymous.
Analytics, attribution and subscription services also use device or installation identifiers. On iOS, IDFA access depends on your App Tracking Transparency choice. Android advertising identifiers depend on the applicable device settings and SDK configuration. Declining iOS tracking does not disable all analytics: usage and diagnostic events and some attribution signals may still be processed without IDFA.
3.4 Usage and diagnostics
We collect which screens you open, which features you use, and events such as starting a session, answering a question, or opening the subscription screen. We also collect technical data through the integrated services: device model, operating system version, language, country, and app version.
If Chartle crashes, we receive a crash report containing the technical state of the app at that moment. Reports may include stack traces, device details and diagnostic context; we do not intentionally include your display name in crash reports.
3.5 Purchases
If you buy a subscription, the purchase is made through Apple or Google, not through us. We never see or receive your card number, billing address or bank details. What we receive is the fact that a subscription exists, its product identifier, its status, and the store's transaction identifiers, so the app knows to unlock the paid features on your device.
3.6 Notifications
If a free trial is available to you and you accept the system prompt, Chartle schedules one local reminder before the trial ends. It is generated on your device by the app itself, without a push-notification server or push token. The app separately records whether notification permission was granted and whether a notification brought the app to the foreground as usage analytics.
3.7 Website waitlist
If you choose “Get notified” on chartleapp.com, we collect the email address you submit, the signup timestamp and a source label identifying the landing page. These are stored in Firestore to send the launch notification you requested. You can ask us to remove your address by contacting chartle@buffalostudio.co.
3.8 Website analytics and cookies
chartleapp.com loads Google Analytics to measure visits and use of the website. It can collect page views, referring pages, browser and device information and cookie-based visitor and session identifiers. Google Analytics uses first-party cookies such as `_ga` for this measurement. This website measurement is separate from the mobile app's tracking permission and from signing up to the waitlist.
You can block or delete cookies using your browser settings, or use Google's Analytics opt-out browser add-on. These controls do not by themselves delete information already collected. Google explains its cookie use in its Analytics cookie documentation. The website's waitlist code does not send the submitted email address to Analytics as an event parameter or profile property.
4. Why we process it, and on what basis
| Purpose | What it uses | Legal basis (KVKK / GDPR) |
|---|---|---|
| Running the app and keeping your progress | Onboarding answers, progress, device-linked identifier | Performance of a contract |
| Setting your pace, tracking the shared learning path and offering revision | Onboarding answers, progress | Performance of a contract |
| Managing subscriptions and unlocking paid features | Purchase status, product identifiers | Performance of a contract |
| Keeping the app working, fixing crashes, preventing abuse | Diagnostics, technical data | Legitimate interest |
| Understanding which features are used and improving them | App and website usage events, technical data | Legitimate interest; consent where required for analytics cookies |
| Measuring advertising performance | Attribution events and identifiers, including IDFA when authorised | Consent where required; applicable permissions and device settings govern advertising identifier access |
| Sending a requested website launch notification | Waitlist email, signup timestamp and source | Consent |
| Meeting our legal and accounting obligations | Subscription records | Legal obligation |
Where we rely on consent, you may withdraw it at any time — for tracking, in your device's privacy settings; for notifications, in your device's notification settings. Withdrawal does not affect processing carried out before it.
5. Who we share it with
We do not sell personal data. We use analytics and advertising measurement providers to understand usage and measure and optimise Chartle campaigns.
We use a small number of service providers who process data on our instructions:
- Google (Firebase Authentication, Cloud Firestore, Analytics, Crashlytics, Remote Config, website Google Analytics and hosting) — device-linked and installation identifiers, onboarding answers, app usage events, crash reports, website analytics data and waitlist entries, according to the service used.
- Mixpanel — usage events, selected onboarding preferences and screen views, associated with a pseudonymous device or installation profile.
- AppsFlyer — install attribution, selected conversion events and device or installation identifiers, including advertising identifiers where available and permitted. Configured partner integrations may forward conversion events.
- Meta (Facebook App Events and configured attribution integrations) — selected app engagement and conversion events and identifiers for advertising measurement and campaign optimisation.
- RevenueCat — subscription status, transaction and app-user identifiers, and identifiers used by configured analytics and attribution integrations, so the app can unlock paid access and measure subscription conversions.
- Apple and Google, as the stores that process the payment itself.
We may also disclose data where a law, a court, or a competent authority requires it, and where it is necessary to establish, exercise or defend a legal claim.
6. Transfers abroad
The providers above operate servers outside Türkiye, including in the United States and the European Union. Your data is therefore transferred abroad within the meaning of Article 9 of the KVKK, and, where the GDPR applies, outside the EEA.
We rely on the safeguards those providers offer for such transfers, including standard contractual clauses approved by the European Commission where applicable. You may request a copy of the relevant safeguard using the contact address in section 1.
7. How long we keep it
Deleting the app normally removes its local application data. Secure identifiers may persist, and deleting the app does not delete data already held in Firestore or by other providers. On reinstall, some onboarding answers and progress may be restored. Local-only lesson checkpoints and accuracy comparisons are not currently guaranteed to restore. Contact us to request deletion of server-held data.
Data held by our providers under device-linked, installation or cookie identifiers is kept while your installation is active and for a reasonable period afterwards, subject to provider retention settings and our operational and legal needs. The app does not currently implement automatic deletion of inactive Firestore profiles. We assess deletion requests through the contact address below.
Records connected to a purchase are kept for as long as tax and commercial legislation requires us to keep them, which is currently ten years under Turkish law.
8. Age limitation
Chartle is intended for users aged 16 and over, and it is not directed at children. Its subject matter — reading financial charts — is not suitable for younger users.
We do not knowingly collect data from anyone under 16. If you believe someone under 16 has used Chartle, write to chartle@buffalostudio.co and we will delete what we hold.
9. Your rights
Under Article 11 of the KVKK, and under the GDPR where it applies to you, you may ask us to tell you whether we process your data and to give you a copy of it; to correct it if it is wrong or incomplete; to delete it; to restrict or object to how we use it; to transmit it to another controller where that is technically possible; and to tell you who we have shared it with. You may also object to a decision produced solely by automated analysis, and claim compensation for damage caused by unlawful processing.
Chartle makes no decision that produces a legal effect for you. The app adapts which questions it asks and which patterns it shows; nothing more.
Send requests to chartle@buffalostudio.co. We answer within thirty days at the latest, and free of charge unless the request is manifestly excessive or repetitive. Because Chartle has no user login, please write from the address you wish us to reply to and tell us as much as you can about your installation; without something to match, we may be unable to locate any data that relates to you.
You also have the right to complain to the Turkish Personal Data Protection Authority (KVKK), or, in the EEA, to your local supervisory authority.
10. Security
Data in transit is encrypted. Data held on your device is stored in the application's own storage area, which the operating system isolates from other apps. Access to the tools listed in section 5 is restricted to the people who need it.
No system is perfectly secure, and we do not claim otherwise. What we can say is that the amount of personal data Chartle holds is deliberately small: there is no account to compromise and no payment detail to lose.
11. Marketing
The mobile app does not ask for an email address. The website has an optional waitlist for the launch notification you request. We do not use that signup as permission for unrelated marketing messages. Contact us to withdraw your request or have your waitlist entry removed. Advertising measurement and campaign optimisation through the providers in section 5 are separate from these emails.
12. Changes to this policy
If we change how Chartle handles personal data, we will update this page and change the date at the top. If the change is significant, we will say so in the app before it takes effect.
13. Contact
Buffalo Dijital Hizmetler A.Ş.
Cevizli Mah. Zuhal Cad. A Blok No: 46/50, 34846 Maltepe / İstanbul, Türkiye
chartle@buffalostudio.co
chartleapp.com