Email Warm-upFree email warm up that gets your new mailboxes out of spam
Email warm-up builds a mailbox's sending reputation before real outreach: a slowly growing number of ordinary emails that get opened, replied to and pulled out of Spam, 3 a day rising to 30 over 14 days. This tool does it free: connect two or more mailboxes and they warm each other in a private pool nobody else can see.
GmailGoogle Workspace
Zoho
Lark
Yahoo
SES
SendGrid
Mailgun
Any IMAPJoin 5,000+ users warming up emails together
Mailboxes in Kuala Lumpur write to colleagues in London. Singapore replies to New York. Every dot on the globe is a mailbox being warmed right now, every arc a warm-up email landing in a real inbox and being read.
Hover the globe to watch the traffic. Drag to spin it yourself.
Works with the mailboxes and sending platforms you already use
Mailboxes connect with Google sign-in, the Zoho API or an app password. Sending platforms connect with their SMTP credentials and the inbox that receives the replies.
OutlookHow email warm up works here
Mailbox providers score a sender on history: volume, opens, replies, and whether mail gets pulled out of spam. Your private pool manufactures that history for you, slowly and naturally. Connect at least two mailboxes.
Connect a mailbox
Google sign-in for Gmail and Workspace, an app password for Zoho, Lark or any IMAP server. Takes under a minute.
It joins your pool
Your mailboxes start writing short, normal office emails to each other, and write back. Only your own mailboxes, never anyone else's.
Spam gets rescued
Every warm-up email that lands in Spam is moved to the inbox, opened and replied to. That is the strongest signal a provider can get.
Ramp to ready
Volume grows from 3 a day to 30. After 14 clean days the dashboard marks the mailbox ready for real outbound.
What you get, free
Everything a paid warm-up tool does, built by BobWork for its own outbound and opened up to everyone.
Human-paced sending
Business hours in your time zone, random gaps, weekends at 30%. Never a burst, never the same pair twice in three hours.
Real two-way threads
About 40% of warm-up mail gets a reply and threads close naturally, the way colleagues actually email.
Spam rescue and read receipts
Warm-up mail in Spam is moved to the inbox, marked read and filed, then archived after a day so inboxes stay clean.
Health score per mailbox
Spam rate measured in real inboxes, errors, deliveries and ramp progress rolled into one number you can act on.
SPF, DKIM, DMARC checks
Every domain in your account is checked daily. Missing records are the number one reason warm-up stalls.
Only warm-up mail is touched
The tool identifies its own emails by header and subject. Your real mail is never read, moved or answered.
Free warm-up versus paid warm-up tools
What you give up and what you keep. Prices read from each vendor's pricing page on 3 October 2026; check before you buy.
| Tool | Cheapest price | Free plan | Pool | Providers | Outlook |
|---|---|---|---|---|---|
| BobWork Email Warm-up | $0, up to 20 mailboxes | Yes, permanent, no card | Private: only your mailboxes | Gmail, Workspace, Zoho (free plan OK), Lark, Yahoo, iCloud, SES, SendGrid, Mailgun, any IMAP | Not yet |
| Warmup Inbox | $19 per inbox / month | No (7-day trial) | Shared, 30,000+ inboxes | Gmail, Outlook, Yahoo, Zoho, iCloud, SES, Mailgun, SMTP | Yes |
| MailReach | $19.50 per mailbox / month | No | Shared, 30k+ inboxes | Any SMTP incl. Gmail, Outlook, Zoho, SES, SendGrid, Mailgun | Yes |
| Lemwarm | $29 per address / month | No (bundled in lemlist) | Shared, 20,000+ domains | Gmail, Outlook, Zoho, Proton, SMTP | Yes |
| Instantly | $47 / month, warm-up bundled | No | Pool of customer accounts | Google, Microsoft | Yes |
| Warmy | From $49 / month | No (7-day trial) | Shared, 1M+ mailboxes | Any ESP | Yes |
| Mailwarm | $69 / month for 1 mailbox | No | Vendor-run, 50,000+ inboxes | Gmail, Microsoft 365, SMTP platforms | Yes |
Full comparisons with cost at 1, 5 and 20 mailboxes: alternatives.
Providers
Connect the mailboxes you actually send from.
| Provider | How it connects | Notes |
|---|---|---|
| Gmail / Google Workspace | Google sign-in, one permission | Works from any device. Google may show an “unverified app” notice: press Advanced, then continue. |
| Zoho Mail | Zoho API (Self Client code) or IMAP + SMTP | The API route works on the free plan with no IMAP. IMAP needs Mail Lite or higher. Both are step-by-step in the app. |
| Lark Mail | IMAP + SMTP with a generated password | An admin enables IMAP/SMTP once, then each user generates a mail-client password. |
Yahoo Mail /  iCloud | IMAP + SMTP with an app password | Generate the app password in the account’s security settings; hosts are pre-filled. |
| Amazon SES / SendGrid / Mailgun | Platform SMTP credentials + the receiving inbox | Warm-up sends through the platform, so its domain and IP reputation is what gets built. Replies and spam rescue happen in the inbox you add. |
| Any IMAP mailbox | IMAP + SMTP | Custom domains and hosting providers. Outlook / Microsoft 365 is coming: Microsoft requires OAuth for mailbox access. |
Guides and tools
Plain-English guides on warm-up, deliverability and running a campaign without a budget.
First time warming up? What to expect
Why your mailboxes are emailing each other, what gets touched, and how to read the dashboard.
Free email warm up, done properly
The 14-day ramp, the free options, and the mistakes that get a new mailbox flagged.
How long does email warm up take?
A day-by-day timeline and the three numbers that say a mailbox is ready.
Why do emails go to spam?
Seven causes, with the check and the fix for each one.
What is an email warm-up network?
How mailboxes warm each other, and shared pools versus private ones.
Warm up Gmail, Workspace, Zoho, Lark, SES and more
Exact settings, records and ramp for each provider and sending platform.
SPF, DKIM, DMARC and blacklist checkers
Plus a warm-up schedule generator. Runs in your browser, no sign-up.
Free email warm up, questions answered
Short answers. The full strategy is public too.
What is email warm up?
Building a sending reputation for a new or unused mailbox by sending and receiving a slowly growing number of normal emails that get opened, replied to and pulled out of spam. Providers like Gmail score senders on this history, so a warmed mailbox lands in the inbox when real outreach starts.
Is it really free?
Yes. No credit card, no trial clock. Up to 20 mailboxes per account.
How long does it take?
Plan on 14 days for an existing domain and 3 to 4 weeks for a brand-new one. A mailbox is marked ready after 14 days with a spam rate under 3% and at least 30 warm-up emails received.
How do you know an email landed in spam?
Both ends of every warm-up email are your own mailboxes. The receiving one checks its Spam folder, so a spam landing is observed directly, then rescued.
Does it read my other email?
No. With Google we request one permission (gmail.modify) and use it only to send warm-up emails, find the warm-up emails your other mailboxes sent, move them out of Spam, mark them read, label and archive them, and reply to some. Real mail is never read, moved or answered. Revoke access any time from your Google account or by removing the mailbox. Details in the privacy policy.
Why are my mailboxes emailing each other?
That is the warm-up working: your own mailboxes exchange short, plain notes, open them, rescue them from Spam and reply, which builds the history providers trust. Nothing goes to anyone outside your account. First time? Here is exactly what to expect.
Can my team use one account?
Yes. Your account has a personal connect link. Anyone who opens it adds their mailbox under your account, so it joins your pool and you see all of them in one dashboard. Other accounts never see or email your mailboxes.
Where does it run?
BobWork operates the service. Read the full approach in the warm-up strategy.
Warm up your first mailbox today
Free for Gmail, Google Workspace, Zoho and Lark. The first emails go out within 15 minutes.