Email is used for login systems, 2FA, and crucial notifications. That's why its extremely important that mail arrives quickly, and in the event of failures, redelivered.
Expect equal reliability whether you send 100 emails a day or 10,000 per second. Our queue, sender, and database servers are masterless with multiple layers of redundancy. If a node in our cluster goes down, mail is immediately requeued on another node. The queue system double checks every email that entered the pipeline results in a success or failure event before moving on.
All our pricing plans offer 14 days of "full-take" logging. That includes the entire mail body, headers, timestamped SMTP session, and other metadata.
When recipient mail servers respond to our mail deliveries with an error we make multiple attempts to redeliver. All of this is measured and visible in the analytics tab of the dashboard.