Documentation/Email Delivery/Using SMTP Relays
Legacy Bridge

Using SMTP Relays

Bridge your existing SMTP configuration with our modern, high-speed delivery engine.

Important: Protocol Translation

Because Aranly runs on modern global Edge infrastructure, standard TCP-based SMTP connections (port 587/465) are often blocked for security and performance reasons. To solve this, our engine automatically translates your SMTP settings into high-speed HTTP requests for supported providers.

How Smart Routing Works

1

Input Your Settings

Enter your host (e.g., smtp.sendgrid.net), port, and credentials in the Custom SMTP card.

2

Automatic Detection

Our engine inspects the host. If it recognizes the provider (SendGrid, Postmark, etc.), it bypasses the slow SMTP protocol entirely.

3

API Delivery

The email is delivered via the provider's REST API using your credentials. This ensures the fastest possible delivery and bypasses all protocol blocks.

Configuration Best Practices

If your provider is supported, we strongly recommend using the HTTP API Card instead of the SMTP card for even better performance.

Authentication

Most modern relays require an API Key (e.g., SendGrid) or an App Password (e.g., Gmail) rather than your main account password. Always use the most restrictive credential possible.

Ports & Encryption

We always attempt Secure (TLS) connections. If your provider supports it, use port 587 or 465. Use of port 25 is not recommended and often blocked by network providers.

Encrypted Credentials

Your SMTP credentials are encrypted with AES-GCM (v2) before being saved to the database. They can only be read by the secure delivery engine during the actual send process.