WarmerlyWarmerly ahead on this row
Sequences, pre-launch checks and one reply inbox, with no cap on sends on paid plans.
Warmerly
Warmbox
One-to-one · Campaign sending
Campaign sending
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
Sequences, pre-launch checks and one reply inbox, with no cap on sends on paid plans.
Warmbox
Warm-up only on the pages we read; its campaigns are warm-up campaigns.
The short answer
Campaign sending, in one look.
Warmerly sends campaigns from the mailboxes it warms: sequences, pre-launch checks and one reply inbox, with no cap on sends on paid plans. Warmbox is warm-up only on the pages we read. Its help centre talks about campaigns, but they are warm-up campaigns. Last checked 22 October 2026.
Warmbox
Warm-up only on the pages we read; its campaigns are warm-up campaigns.
The picture
Drawn side by side.
From mailbox to reply
The steps each product covers
WarmerlyWarmbox
Warmerly
MailboxWarmupSequenceSendReply inbox
Warmbox
InboxWarm-upSpam rateChecker
Both warm a mailbox. We found no outreach sender on Warmbox's pages, so its flow stops at the checker.
What each calls a campaign
As each page uses the word
WarmerlyWarmbox
An outreach campaign
- Email, wait, LinkedIn and branching steps
- Pre-launch checks
- No cap on sends on paid plans
A warm-up campaign
- Analytics, sending parameters, schedule
- Start and stop the warm-up
- Delete an inbox
Warmbox's help collection "Manage my campaigns" covers six warm-up articles.
On screen
What it looks like.
WarmerlySample data
How Warmerly does it
Warmerly, in detail.
Sequences, pre-launch checks and one reply inbox on the mailboxes you warm.
01
Sequences
Email, wait, LinkedIn and branching steps in a list editor or a drag-and-drop canvas, with an AI opener step.
Warmerly product, checked 21 October 2026
02
Pre-launch checks
A readiness check blocks a launch with no usable step or sender, and warns about DNS problems and spam-style copy.
Warmerly product, checked 21 October 2026
03
No cap on sends on paid plans
Starter, Growth and Agency send without a monthly meter. Each mailbox still sends inside its daily limit. Free is capped at 100 sends a month.
Warmerly product, checked 21 October 2026
04
One reply inbox
Replies land in one inbox with LinkedIn replies. A genuine reply stops that lead's sequence by default.
Warmerly product, checked 21 October 2026
05
Launch checks
Before Start, the campaign is checked for steps with content, sending accounts, queued leads, unknown merge tags, a campaign brief for an AI opener, and plan limits. Failures block the start.
Warmerly product, checked 21 October 2026
06
Warnings need acknowledging
A DNS warning on a sender, more than 5 senders on one domain, a missing postal address, a missing tracking domain or spammy copy asks for one acknowledgement and does not block.
Warmerly product, checked 21 October 2026
07
Replies stop the sequence
A genuine reply stops that lead's sequence by default. A bounce stops sequencing and suppresses the address.
Warmerly product, checked 21 October 2026
08
Inbox sync every five minutes
Connected mailboxes are read for new mail every five minutes, and replies appear in one inbox, including LinkedIn replies.
Warmerly product, checked 21 October 2026
09
Each mailbox has its own daily cap
A mailbox sends the lower of its own daily campaign limit and its ramp cap. The ramp can tighten the cap and never raise it above what you set.
Warmerly product, checked 21 October 2026
10
A brake when bounces rise
Once a mailbox's 7-day bounce rate passes 2%, its cap is scaled down. At 7% the mailbox is paused.
Warmerly product, checked 21 October 2026
11
Sends are spaced, never sped up
The minimum wait you set between sends is stretched by a random 0 to 100% per mailbox, and it is never shortened.
Warmerly product, checked 21 October 2026
12
Branching on what a lead does
The canvas editor can branch on opened, clicked, replied or timed out. The list editor is a straight chain of email, wait, LinkedIn and WhatsApp steps.
Warmerly product, checked 21 October 2026
13
Open tracking is off by default
New campaigns do not add an open pixel unless you turn tracking on.
Warmerly product, checked 21 October 2026
14
LinkedIn is separate
A LinkedIn account is $19 a month on top of an email plan, with no trial.
Warmerly product, checked 21 October 2026
How Warmbox does it
Warmbox, in detail.
A warm-up tool. Its "campaigns" are warm-up campaigns.
01
Warm-up only
The home page and pricing page describe warm-up, spam score monitoring and a deliverability checker. No sequence, lead or outreach sender is listed.
warmbox.ai · read 21 October 2026
02
Campaigns means warm-up
The help centre's "Manage my campaigns" collection covers analytics, sending parameters, a custom schedule, folder redirection, start and stop and deleting an inbox.
help.warmbox.ai/en/collections/2749713-manage-my-campaigns · read 21 October 2026
03
Sends emails from your inbox
The warm-up sends emails automatically from your inbox to its network, and the Analytics article counts them as "Emails sent".
help.warmbox.ai/en/articles/4803475-analytics · read 21 October 2026
04
Works beside other senders
The pricing page lists sending-platform inboxes such as Sendgrid and Mailgun as inbox types to warm.
warmbox.ai/pricing · read 21 October 2026
05
The pitch is deliverability
The home page describes Warmbox as helping sales and marketing teams reach their leads by increasing cold email deliverability.
warmbox.ai · read 22 October 2026
06
Warm-up while you send
The help centre says never to turn warm-up off while sending cold emails, because it acts as a constant shield for your sender score.
help.warmbox.ai/en/articles/4803427-what-is-warmbox · read 22 October 2026
07
Sending volume is a warm-up setting
Maximum emails per day, reply rate and timing range are warm-up settings. The sending limit depends on the inbox provider and the Warmbox plan.
help.warmbox.ai/en/articles/4830049-sending-limit · read 22 October 2026
08
Real sending counts toward warm-up size
The volume article says to count outreach, manual and transactional emails together when sizing warm-up, for example 100 outreach plus 50 manual is 150.
help.warmbox.ai/en/articles/13859780-optimizing-your-warm-up-volume · read 22 October 2026
09
Sending platforms as inbox types
Sendgrid, Sendinblue, Mailgun and Amazon SES are listed as inbox types you can connect for warm-up.
warmbox.ai/pricing · read 22 October 2026
10
A paused campaign is a paused warm-up
The troubleshooting article says a paused campaign usually means the connection to your email provider was interrupted, and that you will not lose your progress after reconnecting.
help.warmbox.ai/en/articles/13859617-troubleshooting-paused-campaigns · read 22 October 2026
11
Gmail connection advice
It recommends an app password over Google sign-in for a stable connection, because sign-in can pause a campaign after a security refresh.
help.warmbox.ai/en/articles/4803431-add-a-gmail-google-workspace-inbox · read 22 October 2026
12
Deliverability tips, not a sender
The deliverability guide advises cleaning lists, avoiding bought lists, authenticating, keeping steady volume and using a List-Unsubscribe header.
help.warmbox.ai/en/articles/5239472-what-are-the-good-practices-that-improve-your-deliverability · 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 cold email sequence builder
- A reply inbox for prospect replies
- Any lead or contact data
- Lead or contact data
- Open or click tracking for outreach
Where the sources disagree
We report each version rather than pick one.
- Warmbox uses the word campaign for a warm-up campaign, which can be confused with an outreach campaign.
- The home page frames Warmbox as raising cold email deliverability, while its help centre uses campaign only for warm-up. No page describes it sending outreach.
- The volume article counts manual and transactional emails with outreach; the pricing page sizes plans by warm-up emails a day. The two are not tied together on any page.
The numbers
Only what we could verify.
| Measure | Warmerly | Warmbox |
|---|---|---|
| Campaign sending | Sequences, pre-launch checks and one reply inbox, with no cap on sends on paid plans. | Warm-up only on the pages we read; its campaigns are warm-up campaigns. |
| Campaign sequences | Yes, with LinkedIn and branching | Not listed |
| Cap on sends, paid plans | No cap on sends | Not applicable, warm-up only |
| Reply inbox for prospects | One inbox | Not listed |
| Channels in a sequence | Email, wait, LinkedIn, WhatsApp | Not applicable |
| Bounce rate that scales the cap | Above 2% over 7 days | Not stated |
| Bounce rate that pauses a mailbox | 7% | Not stated |
| Inbox sync interval | Every 5 minutes | Not applicable |
| Default daily campaign limit | 30 a mailbox | Not applicable |
| Campaign sends on Free | 100 a month | Not applicable |
| Warm-up size for 100 to 200 outreach a day | Ramp sets it, 50 a day ceiling | 50 to 100 a day recommended |
| Warm-up trigger to keep running | Keep it on after launch | Never turn it off while sending |
In practice
What it means for you.
Our reading of the facts above. Not a promise, and not the only reasonable reading.
If you send from another tool, this row does not matter
Warmbox can warm the mailbox while Instantly, lemlist or Apollo sends.
If you want one tool
Warmerly warms and sends from the same mailboxes, so a campaign can start as soon as a mailbox is ready.
Do you need a sender at all
If you already send from Instantly, lemlist or Apollo, Warmbox's lack of a sender is not a gap. Compare only the warm-up rows.
One tool or two
Warmerly warms and sends from the same mailboxes. With Warmbox you add a second tool and keep two subscriptions in step.
Mind the volume
Warmbox's table sizes warm-up to your real sending. Warmerly's ramp is by mailbox age, so size your campaign to the day's cap.
Leave warm-up on
Both documents say to keep warm-up running while you send.
Read the launch checks
Warmerly stops a launch for missing content or senders and asks you to acknowledge risky ones. Use the warnings, they are cheap.
Watch bounces
A bounce rate above 2% scales a Warmerly mailbox down. Clean your list first.
Who it suits
Pick the one that fits.
Warmerly
Warmerly is the better fit if
- You want to warm and send from the same mailboxes
- You want pre-launch checks and one reply inbox
- You want to warm and send from the same mailboxes
- You want launch checks that block an empty or unsafe start
- You want replies from email and LinkedIn in one inbox
- You want caps that tighten when bounces rise
- You want sequences with branching and LinkedIn steps
- You want paid plans with no cap on sends
Warmbox
Warmbox is the better fit if
- You only need warm-up and send from another tool
- You do not want a sender in the same product
- You already send from another tool and only need warm-up
- You want a tuning guide that matches warm-up size to real volume
- You want to warm Sendgrid, Mailgun or SES inboxes it names
- You want warm-up settings you can edit day by day
- You want a help library on deliverability basics
- You want a warm-up tool that does not touch your sequences
Questions
Can Warmbox send campaigns?
Not on the pages we read. Its help centre talks about campaigns, but they are warm-up campaigns.
What is Warmerly's default daily limit?
30 a mailbox. Free allows 100 campaign sends a month, and paid plans have no cap on sends.
Should warm-up stay on after launch?
Yes on both. Warmerly says keep it on, and Warmbox says never turn it off while sending.
When does Warmerly slow a mailbox down?
It scales the cap when bounces pass 2% over 7 days and pauses the mailbox at 7%.
Sources
- Warmbox home
- Warmbox help: manage my campaigns
- Warmbox help: analytics
- Warmbox help: sending limit
- Warmbox help: optimising warm-up volume
- Warmbox help: what is Warmbox
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.