Warmup builds your mailboxes' sending reputation before you start cold outreach — and keeps it healthy once campaigns are running.

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).
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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.

Once your mailboxes are set up, run warmup for 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. You can track this progress on the Insights page — see Understanding your Warmup & Deliverability Insights.

Maildoso SMTP mailboxes do not need a gradual ramp-up. Set warmup to 80 emails per mailbox per day from day one and disable any "slow ramp-up" or "increment per day" option in your tool. Starting at 80 on a brand-new mailbox is safe on our infrastructure; ramping from a low number only delays the reputation you're trying to build. You can upload all your mailboxes at once — there is no need to stagger them in batches.

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.

Warm-up email volume is controlled by your warm-up tool provider, not by Maildoso.

To optimize the warm-up process, use the following settings in Instantly for Maildoso SMTP mailboxes:

Follow these settings rather than the generic recommendations shown inside a sequencer or produced by its AI assistant. Sequencers suggest the same conservative schedule to every mailbox provider; these are the settings tuned for Maildoso mailboxes, and mixing the two leads to conflicting advice.

Some tools cap warmup below 80 — Plusvibe and EmailBison max out at 50/day. In that case set warmup to their maximum (50) from day one, disable their slow ramp-up, and lower your campaign volume to roughly 10/day to keep the ratio right.

Being capped at 50 is not the same as being flagged for low warmup. When we send you a list of mailboxes that need more warmup, those mailboxes are almost always running well below 50 (for example 10, 20 or 40 a day) — the cap is not what is holding them back. Check the actual per-mailbox warmup numbers first and raise them to the tool's maximum. See I received a "low warmup" alert but my warmup settings look correct.

If a tool throttles new mailboxes and genuinely cannot start at 80 from day one, use 40/day in week 1 and 70/day in week 2, then 80 — don't ramp from single digits.

For Maildoso SMTP mailboxes, set the warmup volume directly to 80 emails per mailbox per day with the daily increment disabled, rather than ramping up gradually. Then, after the 14-day warmup, cap campaign sending at 15 emails per mailbox per day, including follow-ups. You can start at 15/day as soon as the 14 days are done; a campaign slow ramp-up (5 → 10 → 15 over three weeks) is optional when warmup is running at 80/day.

The 15/day is a campaign limit, not a replacement for warmup. Once campaigns start, warmup stays on at 80/day alongside them — warmup is not a phase you finish and switch off. Keeping a high warmup-to-cold-email ratio is what protects the mailbox; the most common cause of deliverability problems we see is the opposite pattern, low warmup with high campaign volume. If you need to change one of the two numbers, reduce campaign volume rather than warmup. See What's the daily email limit per email account? for the exact limits, including Google Workspace and the 100/day campaign cap.

Warmup only helps if the pool it runs in is good, and the single biggest factor is the share of Google Workspace (business Gmail) mailboxes in the pool. Above roughly 18% Google Workspace helps a lot; a pool with a very low Google share builds little reputation where it matters most. Ask your tool's support what that share is for your mailboxes and ask them to raise it if it's low — Instantly currently runs one of the stronger pools, and Plusvibe will adjust the Google share on request.

Content variety matters too. If a tool sends the same subject and body from every mailbox for weeks, that template itself starts landing in spam and drags your reputation down with it. Prefer a pool that varies subjects and bodies, or use generic, varied warmup content rather than your own campaign copy.

If you target personal @gmail.com recipients (B2C), corporate pools build little reputation on Gmail's consumer servers. Add a Gmail-based warmup (for example warmupip.com) for those mailboxes on top of your regular warmup.

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.

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.

📹 How to Scale to 100K Emails/Month Without Killing Deliverability — how teams set up infrastructure, warm mailboxes, and spam-test to scale volume safely.

Related: Warmup Filters.