Warmup gradually builds your mailboxes' sending reputation before you start cold outreach.
Do you sell mailboxes that are already warmed up?
No. Every mailbox is delivered fresh — Maildoso does not sell "pre-warmed," "already warmed up," or otherwise reputation-built mailboxes at any volume, including bulk/agency orders. We also do not run warmup automatically or on your behalf (see below).
The email accounts are new, so you'll need to start the warmup process using a third-party email sequencer; it takes about two weeks to build up your reputation, after which you can scale up your email campaigns.
How it works
Once your mailboxes are set up, warmup ramps the daily volume up over roughly two weeks so the mailboxes build a healthy history before you scale into real campaigns. Keep warmup running continuously — pausing it interrupts that reputation-building. Wait until the health score of your mailboxes exceeds 90% before starting email campaigns. This ensures that your email accounts are fully prepared for outreach and reduces the risk of deliverability issues.
Do I need to start warmup myself?
Yes. Buying mailboxes does not automatically start warmup, and Maildoso does not run a background or managed warmup pool on your behalf. Warmup runs through the sequencer you connect your mailboxes to (for example Instantly or Plusvibe — both have good warmup pools). Turn warmup on inside that tool and keep it running.
How to Set Up Warmup in Instantly
Step 1: Upload Your Mailboxes to Instantly
Export your mailboxes from your email provider. If using a platform like Maildoso, export all accounts into a CSV file compatible with Instantly.
Log in to Instantly and navigate to Dashboard → Email Accounts → Add Accounts/SMTP Upload.
Upload the CSV file. Instantly will automatically detect and configure the SMTP settings for the uploaded accounts.
Once the accounts are added, enable the warm-up feature for each mailbox.
Step 2: Recommended Warm-Up Settings
To optimize the warm-up process, use the following settings in Instantly:
Increase per day: 1
Daily warm-up limit: 10
Reply rate: 30%
Ensure the option to "Disable slow warm-up" is turned off. Keep the warm-up running for at least 14 days. Wait until the health score of your mailboxes exceeds 90% before starting email campaigns.
Recommended daily limits
A safe target once mailboxes are ready is around 80 emails per mailbox per day total, split evenly — ~40 warmup + ~40 outreach (a 50/50 mix) — rather than maxing out a single mailbox or leaning mostly on outreach. See What's the daily email limit per email account? for the exact limits. During the initial warmup phase, set the daily warm-up limit to 10 emails per mailbox and gradually increase it by 1 per day until reaching the target of ~40 warmup emails per day.
A warmup tool shows a high spam rate, but I haven't sent any campaigns
If a third-party tool (Mailivery, Mailwarm, etc.) reports a high spam percentage on mailboxes that have only been warming up and have sent zero campaign emails, the most common cause is a weak warmup pool in that tool — not a problem with your domain or mailboxes.
Two things to keep in mind: (1) our dashboard reputation and a single third-party seed-list placement test measure different things, and a one-off test is a snapshot that can vary; (2) Gmail is much stricter than Outlook, so a weak pool often shows up as poor Gmail placement specifically. If you're seeing this, switch warmup to a stronger pool such as Instantly or Plusvibe at roughly 50–80/day — placement typically recovers within a few days. If it persists, contact support so our deliverability specialist can review the account.
A note on "Premium warmup"
The Maildoso AI Premium Warmup add-on is no longer available for new subscriptions — you can't purchase it if you don't already have it. If you're an existing subscriber, your premium warmup continues as normal; you don't need to do anything differently. If you don't have this subscription, warm your mailboxes through your sequencer as described above.
Related video
📹 How to Scale to 100K Emails/Month Without Killing Deliverability — how teams set up infrastructure, warm mailboxes, and spam-test to scale volume safely.