Privacy Policy

1. Information We Collect

1.1 Telegram Data Processed by the Extension

When you use the Mastros Chrome extension, the extension may process data visible to you within Telegram Web, including:

• usernames and display names
• public profile information
• group and channel membership information
• groups you share with another user ("mutual groups")
• message content and timestamps
• media files in a conversation (photos, videos, documents and voice notes)

This data is processed locally within your browser and is exported directly to your device as CSV, JSON or ZIP files. It is never transmitted to Mastros servers or to any third party. You can only export data from conversations you already have access to within Telegram.

The extension does not collect, request or store any Telegram credentials. It does not ask for a phone number, a login code, a Telegram API ID or a Telegram API hash, and it never sends messages, adds members or performs any other write action in Telegram. It works read-only through the Telegram Web session you are already signed into.

1.2 Account and Billing Information

The extension has no login of its own and does not collect passwords or credentials.

The extension does not collect the email address of your Chrome profile. It includes a check for whether one is available for billing purposes, but with the permissions it requests the browser does not return an address, so none is obtained and none is transmitted. Installations run in guest mode until a purchase links them to a billing record.

We hold an email address in only two cases, both of which you initiate:

• you complete a paid subscription, in which case Stripe collects your email address on its own hosted checkout page and provides it to us so we can identify your subscription; or
• you enter an email address yourself in order to restore a previous purchase, in which case it is sent to our backend service to locate that subscription.

An email address held for either reason is used only for billing and subscription support. It is never used for marketing, never shared with third parties, and never attached to analytics events.

Payments are processed by Stripe, Inc. Mastros does not store credit card numbers or any other payment details. Stripe may process personal information in accordance with its own privacy policy.

1.3 Website Analytics

The Mastros website uses Cloudflare Web Analytics to understand how visitors interact with the site. This may include page views, browser type, approximate geographic region, device type, and referral source. Cloudflare Web Analytics is designed to be privacy-friendly and does not use client-side cookies for tracking.

1.4 Extension Diagnostic and Usage Data

When the Chrome extension is used, we collect limited product-analytics and diagnostic information through PostHog (EU region, eu.i.posthog.com), including:

• extension version and interface language
• feature usage events (for example: an export was started, completed or cancelled; a plan quota was reached; an upgrade was clicked)
• export counts and durations
• diagnostic error reports
• your plan tier

These events never contain Telegram content. No message text, usernames, display names, contact details, group names or exported rows are included in any analytics event, and no email address is attached to them.

The extension also generates and stores three identifiers:

• a random device identifier, generated on first use and stored in your browser, used as the anonymous key for analytics events;
• a random install identifier, stored in Chrome's synchronised extension storage so that a paid plan can be restored if you reinstall the extension or set up a new device;
• a browser fingerprint hash — a short one-way hash derived from non-identifying browser characteristics (screen dimensions, language, platform, time zone and a canvas rendering test). Only the hash leaves your device; the underlying values cannot be recovered from it. It is used solely to keep plan entitlements attached to the correct installation and to detect abuse of the free tier.

None of these identifiers is derived from your name, email address or Telegram account.

1.5 Uninstall Feedback

If you uninstall the extension, Chrome opens a feedback page on our website. The address of that page includes your plan tier, the number of days the extension was installed, the total number of rows you exported, your interface language and the extension version. It contains no email address, no identifier and no Telegram data. Completing the feedback form is entirely optional.

1.6 Contact and Support Information

If you contact us via email or the website contact form, we may collect your name, email address, and message content in order to respond to your inquiry. Contact form submissions are processed through SplitForms, a third-party form service.

2. Browser Extension Data Practices

Permissions. The extension requests one host permission, https://web.telegram.org/*, which allows it to read the page content and underlying conversation data of Telegram Web in order to provide its export functionality. It requests no access to any other website and cannot read any other site you visit. It also uses Chrome's storage permission (settings, quota counters and identifiers) and identity permission (the billing account check described in section 1.2, which returns no email address).

Local processing. Exported Telegram data — members, messages, contacts, mutual groups and media — is processed locally in your browser and downloaded directly to your device as CSV, JSON or ZIP files. This data is not transmitted to Mastros servers.

Local storage of extracted data. So that a long export can be resumed after an interruption and re-downloaded without running again, extracted rows are saved in a local database (IndexedDB) inside your browser, associated with web.telegram.org. This database stays on your device. You can delete any stored export session from the extension sidebar at any time, and uninstalling the extension or clearing your browser data removes it.

Backend services. Account management, billing, plan and quota validation, and product analytics involve communication with our backend service, hosted on Cloudflare Workers. The information sent is limited to the identifiers and billing email described in sections 1.2 and 1.4.

Limited use. Data obtained through the extension is used only to provide or improve user-facing functionality, security, support, billing, and abuse prevention. We do not sell data obtained through the extension to data brokers. We do not use data obtained through the extension for advertising purposes, and we do not transfer it to third parties except the service providers listed in section 4.

3. How We Use Information

We use collected information to:

• provide and maintain the Service
• process payments and manage subscriptions
• enforce plan limits and prevent abuse of the free tier
• respond to support inquiries
• improve the product and website experience
• detect and prevent abuse or misuse
• comply with legal obligations

4. Data Sharing

We do not sell or rent personal data.

We may share information with service providers necessary to operate the Service, including:

• payment processing — Stripe, Inc.
• extension product analytics — PostHog (EU region)
• website analytics — Cloudflare
• form processing — SplitForms
• infrastructure and hosting — Cloudflare

These providers receive only the information required to perform their services. No provider receives Telegram conversation data, because that data never leaves your device. We may also disclose information if required by law, legal process, or to protect the rights and safety of Mastros or others.

5. Data Storage and Retention

The extension stores configuration settings, export preferences, session state, usage counters and the identifiers described in section 1.4 locally in your browser using the browser storage APIs. Extracted export data is stored locally in the browser database described in section 2. All of this data is under your control and is removed when you delete a session, clear your browser data, or uninstall the extension.

Exported files are stored on your device unless you choose to store them elsewhere. Mastros does not retain Telegram conversation data on its servers.

Account, billing, analytics, and diagnostic data may be retained for as long as reasonably necessary for operational and legal purposes. We periodically review retention and delete data that is no longer needed.

6. International Transfers

Information collected through the Service may be processed in countries other than your own. Extension analytics are processed in the European Union. Payment processing (Stripe) and infrastructure (Cloudflare) may involve processing in the United States and other jurisdictions. By using the Service, you acknowledge that your information may be transferred to and processed in jurisdictions that may have different data protection laws than your own. We take reasonable steps to ensure that information is treated securely.

7. User Rights

Depending on your jurisdiction, you may have certain rights regarding your personal information, such as the right to access, correct, delete, or restrict processing of your data. To exercise these rights, please contact us at admin@mastros.online. We will respond to requests within a reasonable timeframe.

Because analytics and quota records are keyed to random identifiers rather than to your name, please include the email address linked to your billing account, or contact us from that address, so we can locate your records.

8. User Responsibility

Users are responsible for ensuring they comply with:

• Telegram's Terms of Service
• applicable privacy and data protection laws
• any other applicable regulations in their jurisdiction

Users must only export data they have legitimate access to and are solely responsible for the downstream use of exported data.

9. Security

We implement reasonable technical and organizational measures designed to protect the integrity and security of the Service. However, no method of transmission or storage is completely secure, and we cannot guarantee absolute security.

10. Children

The Service is not directed to individuals under the age of 16. We do not knowingly collect personal information from children. If you believe we have inadvertently collected such information, please contact us so we can take appropriate action.

11. Changes to This Policy

We may update this Privacy Policy from time to time. Changes will be posted on this page with an updated revision date. Your continued use of the Service after changes are posted constitutes acceptance of the updated policy.

12. Contact

For privacy or support inquiries: admin@mastros.online