How it works
Automate warm-up across the campaign lifecycle.
Connect the address you send from, choose a gradual volume ramp, and keep warm-up running whenever your mailbox needs reputation support. MailboxWarm sends to controlled seed inboxes, runs configured interactions, and records each result.
01 · Add and connect a mailbox
Use the mailbox you already send from.
Add a Gmail, Microsoft 365, or SMTP address—no separate MailboxWarm email account required. MailboxWarm shows the provider-specific connection method and verifies it before that address can warm.
Read the connection guidesExample setup · not a live connection
Choose your provider
App Password
Microsoft sign-in
SMTP credentials
Save an address now. Supply credentials only when your connection method is available.
App sign-in does not authorize your email mailbox.
Set your pace
Schedule previewStart small. Increase gradually. Keep a daily ceiling.
Illustrative schedule. Your plan and provider limits still apply.
02 · Choose a plan and schedule
Choose the starting volume and daily ceiling.
Set how many warm-up messages to send on day one, the daily target, sending hours, and timezone. MailboxWarm automates the day-by-day increase without exceeding that mailbox’s plan.
Each address has its own plan. Upgrade after payment, or choose a lower tier for the next renewal. Changing plans does not reset your daily usage or resume warming.
Review mailbox plans03 · Run and review
Let the daily warm-up run automatically.
After you choose Start warming, MailboxWarm sends scheduled messages to controlled seed inboxes. Based on configured seed behavior, those accounts can mark messages read, move spam to the inbox, and reply. No prospect list or campaign send is involved.
Use the activity history to review submissions, first observed seed placement, rescues, read flags, and replies. Missing observations remain unknown instead of becoming a guessed score.
Follow the whole journey
Example activity · click a step
A send is not a delivery confirmation. Missing observations remain unknown.
What is email warm-up?
Email warm-up is gradual sending and engagement intended to support sender reputation. MailboxWarm automates warm-up conversations between your mailbox and seed inboxes we operate, including opens, replies and spam rescue.
Can it help an existing mailbox that lands in spam?
Warm-up can support reputation recovery through gradual activity and seed engagement. It is not a guaranteed fix: authentication, recipient complaints, list quality and your other sending activity also matter. It cannot unblock a suspended mailbox.
Can I keep warming during campaigns?
Yes. Warm-up is intended for before, during and after campaigns. Account for both campaign traffic and warm-up traffic when choosing your daily volume, and stay within your email provider’s limits.
How long does warming take?
There is no single completion date. Your mailbox’s history, sending volume and other deliverability factors affect progress. Review activity and placement over time rather than treating a trial or an illustrative chart as a promised recovery timeline.
Does MailboxWarm send emails to my prospects?
No. MailboxWarm is a warm-up service, not a campaign sender. Its warm-up messages go to our seed inboxes, not to your prospect list. You continue sending campaigns through your own outreach tools.
Which emails can it rescue from spam?
Warm-up emails received by our seed inboxes. Those inboxes can mark a message as not spam and move it into the inbox. MailboxWarm cannot move campaign emails out of a prospect’s spam folder. Initial placement and rescue are tracked separately.
Which providers can I connect?
Our setup handbook covers Gmail, Outlook, Hotmail, Microsoft 365 and named SMTP providers. Requirements vary: some need an app-specific password, a paid plan or a custom domain. Live connections remain unavailable in this development preview.
How do the free trial and cancellation work?
When available, your account can try one mailbox for 7 days at 5 warm-up emails a day. A card is required through Stripe. Unless you cancel in Billing before the trial ends, that mailbox starts Starter monthly at the price shown at checkout. You can also choose a paid plan and end the trial early. Other mailboxes have separate subscriptions. Pausing warm-up does not cancel billing.
Before, during, or after a campaign
Give your next campaign a better
chance of reaching the inbox.
Build sending reputation with automated warm-up. Explore the demo to see the workspace for yourself.