About SendStack
Free, open-source bulk messaging — built for real outreach.
What is SendStack?
SendStack is a free, open-source bulk messaging platform that lets you send personalized emails and WhatsApp messages to hundreds of contacts. Upload a CSV, write your template with variables, and hit send.
No sign-up required. No subscriptions. No data ever leaves your device. Everything runs locally in your browser and on your own server.
Two Ways to Send
- Web App — Full-featured dashboard with SMTP email, WhatsApp QR pairing, CSV upload, template variables, and real-time progress tracking.
- Chrome Extension — Lightweight sidebar that integrates directly into Gmail and WhatsApp Web. Zero backend — everything runs in your browser.
Key Features
- Bulk Email via SMTP — Works with Gmail, iCloud+, Outlook, Yahoo, and any custom SMTP domain.
- Bulk WhatsApp Messaging — Connect via QR code to WhatsApp Web. Includes media attachments up to 16MB.
- CSV Upload & Auto-Detection — Drag and drop a CSV. Columns for email, phone, and name are auto-detected.
- Spin Syntax — Write {Hello|Hi|Hey} and each recipient gets a random variant.
- Anti-Ban Protection — Per-message delays, jitter, batch cool-downs, and daily limits.
- Live Progress — Real-time counters for sent, failed, and skipped. Cancel anytime.
- 100% Offline — No analytics, no tracking, no external servers. Your data stays on your device.
Why SendStack?
Most bulk messaging tools are either expensive SaaS products or require complex API integrations. SendStack is different — it's completely free, runs locally, and requires zero setup beyond your existing email or WhatsApp account.
Whether you're a freelancer reaching out to potential clients, a small business sending updates to customers, or an educator communicating with students — SendStack gives you the tools to do it efficiently and safely.
Built by Qobouli
SendStack is built by Qobouli AI & Dev, a software development studio based in Istanbul focused on building practical, privacy-first tools.
Open Source
SendStack is fully open-source. You can inspect the code, contribute, or fork it for your own use.