Hi,
this is super interesting for me, I have never heard complaint about this.
I’d like to explain how I would set this up.
Let’s say I have 2 campaigns, each 14 emails sent every day. Each campaign has 10.000 subscribers. Both campaigns have to go out 7:00 am in the morning.
It means my output is 20:000 emails.
My ESP is Amazon SES, they allow me 14 emails / sec. that is 1428 seconds or 23 minutes. That is the first bottleneck. Even if I send with full speed available to me, there will be some contacts receiving my email at 7:23.
And as @dirk_s pointed out, Amazon SES will even throttle you, so my real delivery speed might be even less.
These are circumstances outside of Mautic.
But Mautic has also some bottlenecks before you reach that number, so let’s eliminate those:
Use queued email sending
Email sending consists of 2 parts: 1. creation 2. send. Unless you use a queue both processes are done by the campaign trigger command. It takes longer to produce and send, therefor it makes sense to separate and pre-create your emails.
If you use queue emails from the 2 campaigns will be sent out in a mixed manner.
Max out campaign trigger speed
You can measure how long it takes to run the campaign. Make sure your crons are running often enough, in other words when one cron ends, the next one should start. Forget the 15 minute cron, do a one minute cron. In Mautic 5 you can even create campaigns paralel with multiple threads. check the --help command to see more.
Use multi thread sending to push out emails faster
Mautic 5 can do multi-thread sending of emails. The speed is up to you and your resources. Make sure you are not sending too fast, because the feedback loops / clicks / opens can overwhelm your system, not to mention you don’t want to be banned by your ESP for being hyperactive.
Would be nice to understand the total scope by disclosing how many emails you want to send in each campaign.
I hope this helps.