Built for scale, speed, and absolute deliverability
Discover the full feature set powering millions of transactional emails worldwide.
Sub-100ms Asynchronous Dispatch
Our queue workers instantly accept incoming API requests with an HTTP 202 Accepted status code and a unique message ID. Background workers handle Postfix relaying, TLS negotiation, and connection pooling without blocking your application threads.
- Zero request timeouts on high-volume batches
- Automatic exponential backoff retry on temporary mail server deferrals
- Postfix mail transfer agent with optimized local queue buffers
> HTTP POST /api/v1/emails [202 Accepted]
> Rate Limit & Quota Checked (OK)
> Queue Job Dispatched [ProcessEmailDelivery]
> DKIM Signature Injected (2048-bit RSA)
> Postfix Relay Connection [smtp.relaypulse.io:587]
> 250 2.0.0 Ok: Message Delivered (72ms)
Queued
Received via REST API
Dispatched via Postfix
Relayed with STARTTLS encryption
Delivered (250 OK)
Accepted by mx.google.com
Opened (1x1 Pixel)
IP: 192.0.2.1 | Chrome / macOS
Real-Time Event Streams & Telemetry
Debug delivery problems with granular event tracking. Check exactly when a recipient opened your notification, which links were clicked, or why a destination mail server returned a temporary deferral code.
- Open tracking via lightweight transparent GIF pixel
- Click tracking with instant destination redirects
- Full SMTP response logs and raw header inspection
HMAC-SHA256 Signed Webhook Events
Stream delivery updates directly to your backend microservices. Verify request authenticity using HMAC-SHA256 signatures passed in custom headers.
- Events for sent, delivered, bounced, failed, opened, and clicked
- Built-in test event dispatching from the dashboard
- Complete delivery log history with response status codes
{
"event": "email.delivered",
"message_id": "msg_9f8e7d6c",
"recipient": "user@example.com",
"status": "delivered",
"smtp_response": "250 2.0.0 Ok: queued as B4579120038",
"timestamp": "2026-08-22T22:30:00Z"
}