WarmerlyWarmerly ahead on this row
5 on Starter, 25 on Growth, 100 on Agency: $3.80, $1.96 and $1.79 a mailbox.
Warmerly
Warmbox
One-to-one · Inboxes covered and cost per inbox
Inboxes covered and cost per inbox
One row, in depth: what each tool does, the verified numbers, and who each suits.
Warmbox details read from its pricing, home, features, agency and checker pages and its help centre on 21 October 2026.
Warmerly
5 on Starter, 25 on Growth, 100 on Agency: $3.80, $1.96 and $1.79 a mailbox.
Warmbox
1 on Solo, 3 on Start-up, 6 on Growth: $19.00, $26.33 and $26.50 an inbox.
The short answer
Inboxes covered and cost per inbox, in one look.
Warmerly connects 1 mailbox on Free, 5 on Starter, 25 on Growth and 100 on Agency. Warmbox plans cover 1, 3 or 6 inboxes, with a custom plan above that. On listed monthly prices the cost per inbox falls on Warmerly ($3.80, $1.96, $1.79) and rises on Warmbox ($19.00, $26.33, $26.50). Last checked 22 October 2026.
Warmbox
1 on Solo, 3 on Start-up, 6 on Growth: $19.00, $26.33 and $26.50 an inbox.
The picture
Drawn side by side.
On screen
What it looks like.
WarmerlySample data
How Warmerly does it
Warmerly, in detail.
1, 5, 25 or 100 mailboxes, with a price at each size.
01
1, 5, 25 or 100
Free connects 1 mailbox, Starter 5, Growth 25 and Agency 100.
Warmerly product, checked 21 October 2026
02
More than 100
Max is a custom plan for teams that need more than 100 mailboxes.
Warmerly product, checked 21 October 2026
03
Hosted mailboxes are separate
Mailboxes Warmerly hosts for you (OneMail) do not use a plan mailbox slot.
Warmerly product, checked 21 October 2026
04
Gmail, Google Workspace and Microsoft 365
Connect Gmail or Google Workspace with an app password, or sign in with Microsoft 365.
Warmerly product, checked 21 October 2026
05
Annual cost per mailbox
On annual billing, Starter is $190 for 5, Growth $490 for 25 and Agency $1,790 for 100, or about $3.17, $1.63 and $1.49 a mailbox a month.
Warmerly product, checked 21 October 2026
06
Connecting beyond the plan is refused
Connecting a mailbox past your plan is refused with an explanation. Nothing is charged and nothing is deleted.
Warmerly product, checked 21 October 2026
07
Slots are a live count
Disconnecting a mailbox frees its slot at once, so the plan follows what you run today.
Warmerly product, checked 21 October 2026
08
A new mailbox starts warming at once
A newly connected mailbox is created with warmup on, and its first warmup email is planned for about a minute later.
Warmerly product, checked 21 October 2026
09
Connection is tested first
SMTP and IMAP are each tested before a mailbox is saved, so a bad password is found before it pauses a new mailbox.
Warmerly product, checked 21 October 2026
10
Clear errors name the direction
The setup form shows Sending (SMTP) and Reading replies (IMAP) separately, so you can see which side failed.
Warmerly product, checked 21 October 2026
How Warmbox does it
Warmbox, in detail.
1, 3 or 6 inboxes by plan, then a custom plan.
01
1, 3 or 6
Solo covers 1 inbox, Start-up 3 and Growth 6. The page words it as "inbox warm-up".
warmbox.ai/pricing · read 21 October 2026
02
Custom above 6
The Team plan has custom inboxes and no price.
warmbox.ai/pricing · read 21 October 2026
03
Adding an inbox
Its help centre has a collection of 14 articles on adding inboxes, one for each provider it names.
help.warmbox.ai/en/collections/2725610-add-a-new-inbox · read 21 October 2026
04
Google sign-in or app password
A Gmail inbox can connect with Google sign-in (OAuth) or with an app password. The help article says sign-in can occasionally pause a campaign after a Google security refresh and recommends the app password for stability.
help.warmbox.ai/en/articles/4803431-add-a-gmail-google-workspace-inbox · read 21 October 2026
05
Plans are sized by inbox
Solo is 1 inbox warm-up, Start-up 3 and Growth 6. The pricing page words each as inbox warm-up.
warmbox.ai/pricing · read 22 October 2026
06
Add on the fly
The features page says you can add new inboxes, team members or brand workspaces from the dashboard.
warmbox.ai/the-best-email-warm-up-solution-discover-our-features · read 22 October 2026
07
Connect in a couple of minutes
The home page says to connect an inbox in 2 minutes and that no technical skills are needed.
warmbox.ai · read 22 October 2026
08
Google app password recommended
Its help article says Google sign-in can leave a campaign paused after a Google security refresh, and recommends an app password for the most reliable connection.
help.warmbox.ai/en/articles/4803431-add-a-gmail-google-workspace-inbox · read 22 October 2026
09
Reconnect after a token expires
A paused campaign is usually a broken connection. You open the campaign, choose Edit warm-up, go back one step and sign in again or enter a new password.
help.warmbox.ai/en/articles/13859617-troubleshooting-paused-campaigns · read 22 October 2026
10
Switch to an app password
Its token-expiration article calls the app password the permanent fix, and says Google sign-in may need repeating in a few weeks.
help.warmbox.ai/en/articles/6003856-reconnect-your-inbox-after-token-expiration · read 22 October 2026
What Warmbox does not say
We looked, and found no statement on these. That is about its published pages only, not about the product.
- A price for more than 6 inboxes
- Whether a second plan can be bought to add inboxes
- Whether an inbox can be moved from one plan to another without re-warming
- Whether the inbox count includes paused inboxes
- What happens to an inbox you remove, beyond the Delete an inbox article title
Where the sources disagree
We report each version rather than pick one.
- Warmbox's help article presents Google sign-in as the quickest method and the same article recommends an app password for stability. We report both statements.
The numbers
Only what we could verify.
| Measure | Warmerly | Warmbox |
|---|---|---|
| Inboxes covered and cost per inbox | 5 on Starter, 25 on Growth, 100 on Agency: $3.80, $1.96 and $1.79 a mailbox. | 1 on Solo, 3 on Start-up, 6 on Growth: $19.00, $26.33 and $26.50 an inbox. |
| Mailboxes on Free or Solo | 1 | 1 |
| Mailboxes on the next plan | 5 (Starter, $19) | 3 (Start-up, $79) |
| Mailboxes on the biggest priced plan | 100 (Agency, $179) | 6 (Growth, $159) |
| Cost per mailbox, biggest priced plan | $1.79 | $26.50 |
| Cost per mailbox, middle plan | $1.96 (Growth, 25) | $26.33 (Start-up, 3) |
| Cost per mailbox, entry plan | $3.80 (Starter, 5) | $19.00 (Solo, 1) |
| Cost per mailbox, yearly, entry plan | $3.17 | $15.00 |
| Yearly cost per mailbox, middle plan | $1.63 (Growth, 25) | $23.00 (Start-up, 3) |
| Yearly cost per mailbox, biggest priced plan | $1.49 (Agency, 100) | $23.17 (Growth, 6) |
| Seats on a plan | Not part of the plan table | 1, 3 or 6 |
| Gmail connection | Google app password | Google sign-in or app password |
| Microsoft connection | Microsoft sign-in | Outlook 365, method not stated on the pages read |
| Reconnect after a break | Reconnect from the mailbox | Reconnect from the campaign |
The plans
Every plan, side by side.
Warmerly
Free$01 mailbox · capped sends · no card
Starter$195 mailboxes · no cap on sends
Growth$4925 mailboxes · no cap on sends
Agency$179100 mailboxes · client workspaces · API
MaxCustomMore than 100 mailboxes
Warmbox
Solo$191 inbox · 50 emails a day · $15 billed yearly
Start-up$793 inboxes · 250 emails a day · $69 billed yearly
Growth$1596 inboxes · 500 emails a day · $139 billed yearly
TeamCustomCustom inboxes · no price shown
Per month, monthly billing. Warmbox shows a yearly price for each of its three plans ($15, $69 and $139) and no price for Team; read on warmbox.ai/pricing on 21 October 2026. Warmerly's email plans cover mailboxes; its LinkedIn add-on is charged per account on top.
In practice
What it means for you.
Our reading of the facts above. Not a promise, and not the only reasonable reading.
Cost per inbox is the real comparison
Divide each plan's monthly price by the inboxes it covers. Warmbox lands between $19.00 and $26.50. Warmerly lands between $1.79 and $3.80.
Yearly billing narrows it, not closes it
Warmbox yearly prices work out at $15.00, $23.00 and $23.17 per inbox.
Count every mailbox you warm
Add shared sender addresses and secondary domains to the count. At 8 mailboxes, Warmbox would need a custom Team plan, while Warmerly Starter at $19 is exceeded and Growth at $49 covers up to 25.
Prefer an app password on Gmail either way
Both tools recommend or require the stable route: Warmbox recommends an app password over its sign-in, and Warmerly connects Gmail through one.
Test a reconnect before you scale
Disconnect and reconnect one mailbox on each tool and see how long it takes. Warmbox's own paused-campaign guide has five steps.
Think about unused capacity
On Warmbox Start-up you pay for 3 inboxes, so with 2 you pay for an empty slot. On Warmerly Starter you pay $19 for up to 5.
Look at hosted mailboxes if you have none yet
Warmerly can host mailboxes for you, and they do not use a plan slot. Check the hosted-mailbox price separately.
Who it suits
Pick the one that fits.
Warmerly
Warmerly is the better fit if
- You warm 2 or more inboxes
- You expect to grow past 6 mailboxes
- You want hosted mailboxes that do not use a plan slot
- You have 2 or more mailboxes
- You want connection tests to run before a mailbox is saved
- You want to add mailboxes without a call as you grow past 6
- You want the setup form to say whether sending or reading failed
- You want a mailbox to start warming within about a minute of connecting
Warmbox
Warmbox is the better fit if
- You warm exactly one inbox
- You prefer to buy plan sizes of 3 or 6 with a stated team size
- You warm exactly one inbox and pay yearly
- You want brand workspaces and team members added from the dashboard
- You want a help article for each provider you connect
- You prefer to choose between sign-in and app password for Gmail
- You want a stated team size per plan
Questions
How many mailboxes does each plan cover?
Warmerly covers 1 on Free, 5 on Starter, 25 on Growth and 100 on Agency. Warmbox covers 1, 3 or 6, then a custom plan.
What is the cost per mailbox monthly?
Warmerly is $3.80, $1.96 and $1.79 across its paid plans. Warmbox is $19.00, $26.33 and $26.50.
What is the yearly cost per mailbox?
Warmerly is $3.17, $1.63 and $1.49. Warmbox is $15.00, $23.00 and $23.17.
How do I reconnect a mailbox?
On Warmerly from the mailbox itself. On Warmbox from the campaign.
Sources
- Warmbox pricing
- Warmbox help: add a new inbox
- Warmbox help: add a Gmail inbox
- Warmbox help: reconnect your inbox after token expiration
- Warmbox help: troubleshooting paused campaigns
Warmbox pages were read on 21 October 2026. Plans and wording change, so check the vendor's own page before you decide. Warmerly details come from the product as it runs today.
More features
See it on your own mailbox.
Connect a mailbox. Warmerly runs alongside whatever you send from now, so you can compare before you move anything.
Free plan, no card. Paid plans: 7-day trial, first charge on day 8.