How do I distribute volume across multiple inboxes and campaigns safely?

When you have multiple inboxes serving multiple campaigns, the risk is that one inbox ends up sending way more than its safe daily limit — which flags it as suspicious to Gmail and damages your sender reputation. Here's how to keep that from happening.

The safe daily limit per inbox

35 campaign emails per inbox per day is the hard maximum. DFY inboxes start below that after initial warmup and ramp up gradually until they reach the full 35/day capacity.

You don't raise this manually. If an inbox needs more caution, the platform keeps it below 35; it never sends more than 35 campaign emails from one inbox in a day.

How the platform distributes sends

When you attach N inboxes to a campaign, the platform spreads daily sends evenly across them. If you have 18 inboxes attached and the campaign wants to send 100 emails today, each inbox does roughly 5-6 sends.

The cap is per inbox, not per campaign. So if you run 3 campaigns that all use the same 18 inboxes:

• Each inbox's daily cap (say 35) is the total across all campaigns.
• If Campaign A wants 10 from an inbox and Campaign B wants 25 and Campaign C wants 20, that's 55 total — over the 35 cap. The platform will throttle some of the sends to stay safe.

Keeping it safe

Three things:

1. Let the platform enforce the cap

The per-inbox daily cap is platform-set. Watch the Emails Sent column, but don't try to push an inbox beyond the displayed limit.

2. Think in total daily volume, not per-campaign

If you have 18 inboxes capped at 35 each, your workspace's total daily send capacity is 630 emails per day. Spread that across all your campaigns. Running 5 simultaneous campaigns that each want 300 sends a day (1,500 total) means each inbox gets pushed past its safe cap.

3. Rotate inboxes across campaigns

Don't always use the same inboxes for the same campaigns. Swap which inboxes power which campaign every couple of weeks. This prevents any one inbox-to-campaign pairing from building unhealthy patterns.

A worked example

Say you have 18 inboxes capped at 35 each = 630 emails per day total.

Bad distribution:

• Campaign A: 500 emails/day (pushes 15 of your inboxes to cap)
• Campaign B: 400 emails/day
• Campaign C: 300 emails/day
• Total asked: 1,200/day from 630 capacity → inboxes get throttled, reputation takes a hit

Good distribution:

• Campaign A: 210 emails/day
• Campaign B: 210 emails/day
• Campaign C: 210 emails/day
• Total asked: 630/day from 630 capacity → each inbox does ~35, no throttling

You might want Campaign A to run 500/day. In that case, pause B and C, or add more inboxes.

Related

• Email Accounts overview — see the per-inbox daily count
• Deliverability — why per-inbox caps matter
• Warmup — new inboxes need lower caps during warmup