SendMailer Pro privacy policy

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Effective date: 2026-09-13

1. Who we are (Data Controller)

Trade name: DefinedBytes
Legal entity (Data Controller): DefinedBytes (sole proprietorship registered in Poland)
NIP: 8951760884
REGON: 540945171
Contact (privacy): privacy@definedbytes.com

This Privacy Policy applies to the SendMailer Pro Windows desktop application (“SendMailer Pro”, “the App”).
SendMailer Pro is distributed via the Microsoft Store.

2. What SendMailer Pro does (local-first design)

SendMailer Pro helps you create and send personalized emails from your own email accounts.
The App is designed as “local-first”:

  • recipient lists, templates, attachments, and campaign configuration are stored on your PC,
  • we do not provide any “DefinedBytes mailboxes” or vendor email servers,
  • we do not route your email content through DefinedBytes servers.

Emails are sent through the provider and connection method you configure, such as Gmail SMTP, Microsoft 365/Outlook SMTP with Microsoft OAuth, another SMTP provider, or a previously saved Gmail API account.

3. Data stored and processed locally on your device

Depending on the features you use, the App may store locally on your device (under your Windows user account):

  • sender account configuration (e.g., host/port for SMTP, sender identity, sending method)
  • authentication details required by the selected connection method, such as an SMTP password or app password, or OAuth tokens for a connected Google or Microsoft account
  • recipient lists and custom fields used for personalization (your contacts database)
  • templates and message content you create (subject/body)
  • attachments you choose to store or generate, and sending history/logs (if enabled)
  • campaign settings (e.g., scheduling, send interval, account rotation, pause/retry rules, blocklist)

SMTP passwords and OAuth token caches are protected locally using Windows data protection for the current Windows user account. This protection does not mean that the entire contacts database, your exports, or every local log file is encrypted by the App.

DefinedBytes does not receive this local data unless you explicitly choose to share it with us (for example, by contacting support and attaching logs/files).

4. Email sending and third‑party email providers

When you send an email, the App transmits the email data you choose to send (recipient addresses, subject, body, and attachments) to:

  • your selected email provider’s servers / APIs (e.g., Gmail API, Microsoft services, or an SMTP server configured by you), and
  • the intended recipients and their email providers / mail servers as part of email delivery.

This transmission is necessary for sending the email and is initiated by you (the user).

5. Gmail connection methods and Google permissions

The current account setup offers Gmail SMTP with an app password. This method signs in to Gmail's SMTP server using the credentials you provide; it does not use the Gmail API gmail.send OAuth permission.

Previously saved Google OAuth accounts remain supported by the App's account model. Their permissions depend on the connection method:

  • Gmail API accounts use https://www.googleapis.com/auth/gmail.send to send messages.
  • Legacy Gmail SMTP OAuth accounts use https://mail.google.com/. This is a broader Google permission than sending alone; it also grants mailbox access capabilities. The App's implemented sending workflow uses it to authenticate to Gmail SMTP and send the messages you create.

The App does not provide an inbox-reading or mailbox-history feature. This describes its implemented functionality; it does not narrow a permission granted on Google's consent screen.

OAuth tokens are stored locally on your device. You can review and revoke Google access in your Google Account's third-party connections settings. Revoking access does not itself erase every locally stored file or cached credential.

6. Google user data processed by the App

When you use a Gmail connection, the relevant data includes:

  • the email data you choose to send: recipient addresses, subject, body, and attachments
  • the authentication details required by the chosen connection method: an app password for Gmail SMTP, or locally stored OAuth credentials/tokens for a saved OAuth account

SendMailer Pro does not upload your contact database, templates, or campaign history to DefinedBytes servers.

7. With whom we share, transfer, or disclose Google user data

This section explicitly describes with whom we share, transfer, or disclose Google user data.

We do not sell Google user data.

We do not share, transfer, or disclose Google user data to third parties for purposes other than providing the App’s user‑facing functionality you request (sending emails).

When you send a message using a Gmail connection, the message data you choose to send (recipients, subject, body, and attachments) is transmitted to:

a) Google, through Gmail SMTP or the Gmail API as appropriate to the saved account, to send your message; and
b) your intended recipients and their email providers or mail servers to deliver it.

We do not disclose Google user data to advertising platforms, data brokers, information resellers, or for credit‑worthiness/lending decisions.

We may disclose information if required to comply with applicable law, regulation, legal process, or enforceable governmental request, or to protect our rights and security.

8. Google API Services User Data Policy (Limited Use) & AI/ML training

SendMailer Pro’s use and transfer of information received from Google APIs will adhere to the Google API Services User Data Policy, including the Limited Use requirements.

We limit our use of data obtained via Google Workspace APIs (including Gmail API) to providing the user‑facing functionality of the App that you choose (sending emails).

AI/ML model training commitment:
We do not retain or use data obtained through Google Workspace APIs (including Gmail API) to develop, improve, or train generalized / non‑personalized AI or ML models.

9. Diagnostics, local logs, and the telemetry preference

In SendMailer Pro for Windows, Microsoft Store package version 1.0.95.0, no external analytics or crash-reporting provider is configured. The App writes operational diagnostic information to local log files.

The About window retains the preference “Send anonymous usage data (telemetry)”. A new local profile initializes this preference as enabled. In the version named above, the preference has no configured external telemetry provider to send data to. The preference alone should not be interpreted as confirmation that App Center is active.

Local logs may contain technical details, errors, and sending diagnostics. Review logs and files for personal information before choosing to share them with support.

This description is specific to the version named above. It does not establish the behavior of every earlier release. For questions about another version or information you have shared with support, contact privacy@definedbytes.com.

10. Purchases and licensing

Purchases, licensing, and refunds are handled by Microsoft Store. We do not receive your payment card data.
Microsoft may provide us with aggregated sales/usage information in the developer portal.

11. Retention and deletion

Operational data remains in the App's local storage until removed. Copies, exports, log files, and attachments may exist separately. Uninstalling the App should not be assumed to delete files saved outside its managed storage.

In the current version, removing a sending account deletes its account record from the local database. It does not automatically revoke the provider's authorization or guarantee removal of all separately stored OAuth token caches. To revoke access, use the relevant Google or Microsoft account settings. Revocation invalidates access; it does not necessarily delete the local cached files.

For help locating and removing local data, or requesting deletion of information you have shared with DefinedBytes support, contact privacy@definedbytes.com. Do not send passwords, app passwords, or OAuth tokens with a support request.

12. Security

We implement reasonable measures to protect the App and any data it stores locally.
Because SendMailer Pro stores operational data on your device, device security matters. We recommend:

  • protecting your Windows account with a strong password/sign‑in,
  • using device encryption where available,
  • keeping your operating system up to date.

13. Your rights and choices (EEA/UK and other regions)

If GDPR applies, you may have rights to access, rectify, erase, restrict processing, object, and data portability, subject to applicable law.
Because the App is local-first, you can typically exercise many of these rights by deleting or modifying your local data on your device.
For requests or questions, contact: privacy@definedbytes.com.

If you are a California resident and applicable law applies, you may have certain rights to request information or deletion, subject to legal limitations.
We do not sell personal information.

14. Changes to this policy

We may update this policy from time to time. The latest version will be published with a new effective date.