Woodpecker recommends 25 to 35 cold emails a day per mailbox. Your provider allows far more, and hitting its cap is what gets a mailbox blocked. Adaptive sending lowers your volume before you get there.
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Median reply rate by average emails a day, per mailbox. The green bar is the 21 to 50 band our recommendation sits inside.
Adaptive sending works in the background while your campaigns run, counting what has gone out from each connected email account that day.
It checks that count against your provider's limit for the mailbox, and automatically adjusts its sending volume when necessary.
It reduces your sending volume by 50% for 24 hours or by 10% for 10 days. Neither cut runs past its own window.
Sending continues in smaller amounts rather than stopping, a notice appears on the campaign, and it tries to return to your original sending parameters.
| One mailbox, one busy day | Without adaptive sending | With adaptive sending |
|---|---|---|
| Volume nears your provider's cap | Without adaptive sending Nothing changes | With adaptive sending Volume drops 50% or 10% |
| You cross the limit | Without adaptive sending Provider blocks the mailbox | With adaptive sending Sending continues in smaller amounts |
| Your campaign that day | Without adaptive sending Paused up to 48 hours | With adaptive sending Keeps running, slower |
| How you find out | Without adaptive sending A campaign error | With adaptive sending A notice on the campaign |
| The day after | Without adaptive sending You lower the limit yourself | With adaptive sending Tries to restore your settings |
| What it costs you | Without adaptive sending Sender reputation, over time | With adaptive sending Nothing, it is on every plan |
Your provider sets a hard cap, you type a daily limit, and we recommend 25 to 35. Adaptive sending replaces none of the three.
Woodpecker suggested it when you connected the email account, and you can change it in Settings under Accounts. A number you type stays where you typed it.
A random interval between sends, here 140 to 320 seconds, so a mailbox does not fire its whole day in one burst. It is its own setting, not adaptive sending.
The 15 emails an hour follows from the send interval. There is no hourly field in this panel for you to fill in.
It reads "Monitor sending volume to prevent the account from being blocked." On by default, per email account, on the Sending tab.
One thing you never have to do, and three things this feature will not do for you.
Adaptive sending is free on every plan and runs on every email account from your first campaign. There is nothing to switch on.
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A bad address still bounces. Bounce rate is a separate part of cold email deliverability, and list verification is the thing that handles it.
Our system only reduces the number of emails sent. A Microsoft mailbox restricted for volume is unblocked by hand in the Microsoft Defender portal.
The benchmark figures above measure cold email in general, not this feature. You will not find a before-and-after on blocked mailboxes here.
Fewer than an established one, and a new mailbox should not run campaigns yet. Warm it up first. During warm-up, Woodpecker holds the volume below whatever daily limit you set. Once it is warmed up, the usual 25 to 35 applies, with 50 as the ceiling. We publish no ramp beyond that: we have no data for one.
It is on by default, on every email account. To turn it off, open the account's Sending tab and find, under Sending limits, the switch labeled "Monitor sending volume to prevent the account from being blocked." The app and the Help Center call it Bounce Shield. We recommend leaving it on: turning it off does not raise your provider's cap.
Yes, while it is acting. Sending continues in smaller amounts rather than stopping, so the same volume takes longer. The cut is either 50% for 24 hours or 10% for 10 days, and neither runs past its own window. Across a week, the most it takes out is about a tenth of what you planned.
Sending from that mailbox stops. Your provider blocks it, and the app puts that block at up to 48 hours. Woodpecker pauses that mailbox's campaigns for the duration, then starts them again on its own. Do it often and you risk longer blocks and a damaged sender reputation.
A free Gmail account allows 100 messages a day via SMTP, 20 an hour. The 500 that people quote is the browser limit, not SMTP. Google Workspace publishes 2,000 a day. Our own limits article advises no more than 100 a day, whatever your provider allows. For cold outreach we recommend 25 to 35 per mailbox, never over 50.
There is no single number, because volume is only one of the inputs into cold email deliverability. Bounce rate, list quality and the writing decide it too. Adaptive sending acts on volume alone. In our data on 56,614 campaigns from 7,000 companies, campaigns under a 2% bounce rate get about 60% more replies than those over 20%.
