This article describes the rate limits implemented by HES, for both outbound and inbound mails.
Rate Limit Settings
- For inbound traffic, the rate limit is based on sender IP and recipient.
- For outbound traffic, the rate limit is based on sender IP and sender.
|Direction||By IP address||By email address|
|Inbound||500 messages per minute per sender IP address||200 messages per minute per recipient email address|
|Outbound||1,000 messages per 5 minutes per sender IP address||500 messages per 10 minutes per sender email address|
- What will happen if the the rate limit has been reached/exceeded?
When the sender IP or the recipient triggers the HES rate limits, HES will temporarily reject the emails from that sender IP or to the recipient, and returns the error code 4xx.
- When will HES accept the emails again?
If the email sender client follows the RFC's definition, the email sender client should re-send the emails based on their resend strategy.