How many emails can you send at once?
The question is not only what your platform allows, but what mail providers will accept from you.
What counts
Your history. A sender who has sent a thousand messages a week for a year can suddenly send ten thousand without trouble. A new domain cannot.
The sudden jump
Multiplying your usual volume tenfold is the pattern that triggers most blocks. It is not the absolute number but the change that draws attention.
What you do for a big campaign
Spread it over several days and start with your most engaged contacts. Their opens and clicks create the positive context for the rest.
Watch during the send
If bounces or complaints rise mid-campaign, stop rather than finish. An interrupted campaign costs less than a damaged reputation.
The practical limit
It is rarely technical. Your list quality and your consistency almost always determine what gets through.
