Short answer
Large audiences are prepared in controlled batches. Preparation can take a few minutes; the campaign becomes Active only when the whole audience is queued.
What you see
After clicking Launch campaign, a progress indicator reports how many emails have been queued so far. It continues automatically until preparation finishes.
Why it works this way
Queueing tens of thousands of messages in one go is fragile — a single interruption would leave the audience half prepared. Batching makes launch resumable and keeps the app responsive.
Important notes
- You can leave the page during preparation; it continues and you can reopen the campaign to check progress.
- Preparation is idempotent, so nothing is queued twice if a batch is retried.
- Preparation speed has nothing to do with sending speed. Sending is governed by your window, your limits and your mailbox capacity.
Common problems
- Stuck on "Preparing your campaign" — see the troubleshooting article on campaigns stuck preparing.
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