Is it possible to set a maximum number of emails sent each day eg. send to a max of 150,000 members each day?
You can set communication limits to control the number of emails sent per day & per week at the individual level (see: Enable Communication Limits - Marketo Docs - Product Documentation), and you can set smart campaign restrictions to limit the number of people that can be run through a campaign (see: Enable Person Restrictions for Smart Campaigns - Marketo Docs - Product Documentation), but AFAIK there's no OOB setting to restrict the number of instance-wide email sends.
Depending on your use case, a combination of communication & smart campaign limits might do the trick.
Thanks for that.
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Further to Grace's answer (which is the correct one and pls mark it as such) the only way to achieve this is to set your volume very low (150,000 won't cut it due to speed-of-light constraints, but 50K would) and qualify everyone via a webhook that maintains a counter. Of course you have to make sure everyone runs through the 'hook, it won't be enforced by the system.
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