Privacy Policy
Last updated: March 29, 2026
Overview
SendStack — Bulk Messaging ("the Extension" / "the App") is a browser extension and web application for Google Chrome that helps you send personalised bulk emails and WhatsApp messages directly from Gmail and WhatsApp Web.
We are committed to protecting your privacy. This policy explains exactly what data the Extension and Web App collect, how it is stored, and what it is never used for.
Data We Collect
The Extension stores the following data locally in your browser using chrome.storage.local and chrome.storage.sync:
| Data | Where Stored | Purpose |
|---|---|---|
| Uploaded CSV rows (contacts) | chrome.storage.local | Populate the send queue; cleared when you upload a new CSV or remove the extension |
| User settings (delay, limits) | chrome.storage.sync | Restore your preferences across sessions and Chrome profiles |
| Daily send counter | chrome.storage.local | Enforce the daily sending limit you configure |
The Web App processes CSV data and SMTP credentials entirely in your browser session and on your self-hosted server. No data is stored permanently on external servers.
Data We Do Not Collect
- No email content is read. The Extension only opens the Gmail compose window and fills in the To, Subject, and Body fields you provide via your template. It does not read, scan, or transmit any existing emails.
- No message history is read. The Extension does not access your WhatsApp message history or contact list.
- No data is transmitted to external servers. All CSV data and settings remain on your device. The Extension makes no outbound network requests of its own.
- No analytics or telemetry. The Extension does not include any analytics SDK, tracking pixel, or crash-reporting service.
- No user accounts. The Extension does not require you to create an account or log in.
Third-Party Services
The Extension does not integrate with any third-party services. It interacts only with:
- Gmail (
mail.google.com) — by injecting a sidebar panel and automating the native compose window. - WhatsApp Web (
web.whatsapp.com) — by injecting a sidebar panel and navigating toweb.whatsapp.com/send?phone=...URLs.
These services have their own privacy policies:
Data Retention
- CSV contact data is retained in
chrome.storage.localuntil you upload a new file or uninstall the Extension. - Settings are retained in
chrome.storage.syncuntil you uninstall the Extension or clear Chrome sync data. - The daily send counter is reset automatically at midnight each day.
Children's Privacy
The Extension is not directed at children under the age of 13. We do not knowingly collect personal information from children.
Changes to This Policy
We may update this Privacy Policy from time to time. Any changes will be reflected in the "Last updated" date at the top of this document and will be committed to the public repository at:
Contact
If you have questions about this Privacy Policy or the Extension's data practices, please open an issue at: