Amazon SES places a limit on the number of messages that can be delivered in a rolling 24-hour period as well as a limit on the messages that can be sent per-second. Blue Matador monitors both of these limits and notifies you if you are approaching them.
The daily quota is the number of messages that can be sent through SES in a rolling 24-hour period. The limit is set per-region and can be increased by contacting AWS support. Blue Matador will send an alert when you are near the daily sending quota so that you can immediately resolve it before messages get rejected.
Hitting the daily quota will cause your application to fail to send messages until the rolling 24-hour value decreases again. If you are using the same SES credentials to send both marketing and transactional emails, this means your users may not receive important emails such as registration and forgot password emails.
To avoid hitting the daily quota, make sure there is an approval process in place for sending large amounts of emails. Amazon may automatically increase your limit if it detects that you are sending high-quality messages and are near your limit, however the automated process for doing this may not happen quickly enough and will cap out at a quota of 1 million messages per day. You can increase the daily quota with a support request, and this is best done before hitting the limit.
The other limit SES imposes on your application is the per-second email rate. Blue Matador approximates your per-second sending rate and will warn you if it is close to the SES limit. Amazon will allow your account to go above the limit temporarily but you will be throttled if consistently over the limit.
To avoid hitting the sending rate limit, you can intentionally slow down the rate you are sending emails. This is usually a reasonable course to take when sending a large number of messages at once that do not need to be received immediately. You may also request a limit increase from AWS support to avoid hitting the limit.