Hi Product Hunt community! 👋 I’m Steve, founder at Bench Tech Audio Ltd (UK). Like many bootstrapped founders running web applications, our biggest recurring nightmare has been transactional email deliverability. A single malicious bot abusing a password-reset endpoint or a form injection attack can spike bounce rates over 5% in a few minutes. When that happens, providers like SendGrid, AWS SES, or Resend will suspend your production domain with almost zero warning—breaking all your login flows and receipts. We couldn’t find a dedicated, lightweight circuit breaker to sit in front of our delivery provider, so we built SentriSend. *🛡️ What SentriSend does: • Pre-flight Threat Filtering: Automatically intercepts and blocks batch credential attacks and internal domain spoofing in real time. • Zero-PII Audit Logging: Logs immutable security telemetry to Supabase with email bodies automatically redacted. • Developer-First: Integrate in 3 lines of code using our official Node.js / TypeScript SDK or cURL. • Global Native Hubs: Full native hubs for English, Japanese (/ja), and Korean (/ko). It’s live at https://sentrisend.com with a generous free tier of 1,000 emails/month. Would love your brutal feedback on our architecture and threat detection rules!

SentriSend

The outbound email firewall to prevent domain bans

The outbound email firewall to prevent domain bans