Send Pace Across Multiple Campaigns (Per-Mailbox Pacer)
Each campaign has a 'Minutes Between Sends' setting that controls the minimum interval between consecutive sends from that campaign. When the same mailbox is used by multiple campaigns (or by warmup at the same time), WarmySender enforces a per-mailbox global pacer on top of the per-campaign setting to protect your account.
How the Per-Mailbox Pacer Works
The pacer is a global throttle that applies to every mailbox. It tracks the last send time from that mailbox — across all campaigns AND warmup — and blocks any new send until the minimum interval has elapsed. This prevents back-to-back sends from any combination of campaigns and warmup activity.
The Floor Is the Longest Interval
If Campaign A has Minutes Between Sends = 5 and Campaign B (using the same mailbox) has Minutes Between Sends = 15, the effective floor for that mailbox is 15 minutes. The longest minimum interval among all campaigns sharing the mailbox wins. This is intentional — the system respects the most conservative setting to keep your mailbox safe.
Warmup Counts Toward the Same Pacer
Warmup sends are not exempt. If warmup just sent an email from your mailbox, the next campaign send is delayed until the Minutes Between Sends interval has elapsed — and vice versa. Your mailbox will not send a warmup email and a campaign email within the same interval window. This ensures the mailbox always looks like a human is at the keyboard, not a bot blasting messages.
Why This Exists: Account Safety and Deliverability
Email providers (Gmail, Outlook, Yahoo) flag bursts of rapid-fire sends as bot-like behavior. A mailbox that sends 5 emails in 30 seconds is a huge red flag — it looks like a compromised account or a spammer. The pacer makes sure every send looks natural and spaced out, protecting your sender reputation across all of your outbound activity.
What You Might Notice
• A campaign may appear to send slower than its 'Minutes Between Sends' setting suggests — that means another campaign or warmup is sharing the mailbox and the longer interval is in effect.
• Your effective throughput per mailbox is capped by the longest interval, not the shortest.
• To increase throughput safely, add more mailboxes to the campaign rather than lowering the interval.
Best Practice
• Use consistent Minutes Between Sends settings across campaigns that share mailboxes, so you know what to expect.
• If you need higher volume, scale horizontally by adding mailboxes — do not lower the interval below safe thresholds.
• Keep warmup running alongside campaigns — the pacer will coordinate both safely.