WarmerlyWarmerly ahead on this row
Every mailbox on the plan, not metered: threaded warmup emails with automated, quoted replies.
Warmerly
Apollo.io
One-to-one · Email warmup
Email warmup
One row, in depth: what each tool does, the verified numbers, and who each suits.
Apollo details read from its pricing page and FAQ, product pages and help centre on 21 October 2026.
Warmerly
Every mailbox on the plan, not metered: threaded warmup emails with automated, quoted replies.
Apollo.io
From Basic, through Warmbox.ai per its help article: 1 mailbox per seat typically included, 200 credits for each extra mailbox every 30 days.
The short answer
Email warmup, in one look.
Both warm mailboxes with real mail between mailboxes. Warmerly warms every mailbox on the plan on a ramp it sets: 4 a day on day 0 to 50 a day by day 30, with Gmail held to 40, Outlook to 30 and Zoho to 25. Apollo's help centre says its warmup runs through Warmbox.ai, a third-party provider, on mailboxes you link, with a minimum and maximum you set (10 and 40 recommended). Paid Apollo plans typically include warmup for 1 mailbox per seat, and each extra mailbox uses 200 credits per 30-day period. Last checked 22 October 2026.
Apollo.io
From Basic, through Warmbox.ai per its help article: 1 mailbox per seat typically included, 200 credits for each extra mailbox every 30 days.
The picture
Drawn side by side.
Warmup volume over the first 30 days
Emails a day, per mailbox
WarmerlyApollo.io
- Warmerly: 4 a day at the start, 50 a day by day 30 (Gmail 40, Outlook 30)
- Apollo: a minimum and maximum you choose, 10 and 40 recommended, 50 the most
Warmerly's line is drawn from its ramp anchors. Apollo publishes no daily curve, only the range you set and a pattern name (progressive, flat or randomised), so its lines are the two limits, not a ramp.
On screen
What it looks like.
WarmerlySample data
How Warmerly does it
Warmerly, in detail.
Warmerly warms each mailbox on a ramp set by Warmerly, then cuts it by provider cap, weekends, spam placement and health. Warmup sends are not a billing meter.
01
The ramp, from anchor points
The daily quota is interpolated between anchors: 4 a day at day 0, 8 at day 3, 15 at day 7, 25 at day 14, 35 at day 21 and 50 at day 30. It counts days the mailbox really sent.
Warmerly product, checked 21 October 2026
02
The ceiling is the lowest of three limits
The quota is the lowest of the age ramp, the provider cap and a hard ceiling of 50 a day. Provider caps are Gmail 40, Outlook 30 and Zoho 25.
Warmerly product, checked 21 October 2026
03
Weekends and health cut it further
Weekends run at 0.6 of the weekday quota. Spam placement multiplies the quota by 0.7 from a score of 10 and 0.4 from 20. A health score multiplies it by 0.75 below 70 and 0.4 below 50. Only the lower of the two health factors applies, not both.
Warmerly product, checked 21 October 2026
04
What a warmup message does
A warmup mail is opened after a delay of 10 to 120 minutes, and the recipient replies with a default probability of 0.3, stopping at thread depth 3. Mail that lands in spam is read, moved to the inbox and answered.
Warmerly product, checked 21 October 2026
05
A peer pool, with terms
Warmup mail is real mail between mailboxes in one pool that includes other customers' mailboxes. A sender does not write to the same recipient twice within 72 hours.
Warmerly product, checked 21 October 2026
06
Included on every mailbox
Warmup is not metered on paid plans, and the Free plan includes it. The limit you feel is the number of mailboxes: 1 on Free, 5 on Starter, 25 on Growth and 100 on Agency.
Warmerly product, checked 21 October 2026
07
A little noise each day
Each mailbox's daily quota is multiplied by a factor between 0.85 and 1.15 that is fixed for the mailbox and date, so volume is not the same number every day.
Warmerly product, checked 21 October 2026
08
The pool sets a ceiling
A sender does not write to the same recipient twice in 72 hours, so a sender doing N a day needs about 3N partners. When nobody is left, the window narrows for that sender only, to 48 then 24 hours, and never lower.
Warmerly product, checked 21 October 2026
09
Stops and probes
A mailbox with warmup switched off gets a quota of 0. A mailbox whose last sends were refused gets 1 send a day as a probe, so it can recover or reach the third refusal and be paused with an email.
Warmerly product, checked 21 October 2026
10
How much is opened
About 90 per cent of warmup messages are opened and about 20 per cent of those are flagged important. The first warmup email of a new mailbox is read after 10 to 20 minutes.
Warmerly product, checked 21 October 2026
11
Where Warmerly is behind
We found no setting for a flat or randomised volume pattern or an end date. The only control we found is a lower daily warmup limit that you can set yourself.
Warmerly product, checked 21 October 2026
How Apollo.io does it
Apollo.io, in detail.
Apollo's warmup is something you switch on per mailbox in settings, with a pattern, an end date and a volume range you choose. Its help article names a third-party provider.
01
Run through a third-party provider
The help article says "Email warmup is conducted through Warmbox.ai, a third-party provider" and that Apollo does not control or take responsibility for it. The deliverability page says plans include automated warm-up without naming the provider.
knowledge.apollo.io/hc/en-us/articles/26772718460045-Use-Email-Warmup-to-Improve-Deliverability · read 22 October 2026
02
On Basic and up
The pricing page lists Deliverability Suite & Email Warmup on Basic, Professional and Organization. The help article says warmup is available on select plans.
apollo.io/pricing · read 22 October 2026
03
You choose the pattern and range
You pick Progressive (recommended), Flat or Randomized, an end date (a minimum of two weeks recommended), a minimum and maximum number of emails a day (10 and 40 recommended, 50 the most), and a reply rate (30% recommended, 45% the most).
knowledge.apollo.io/hc/en-us/articles/26772718460045-Use-Email-Warmup-to-Improve-Deliverability · read 22 October 2026
04
One mailbox per seat is included
The help article says paid plans typically include warmup for 1 mailbox per seat, and each additional linked mailbox uses 200 credits per 30-day billing period. On free plans each linked mailbox uses 200 credits.
knowledge.apollo.io/hc/en-us/articles/26772718460045-Use-Email-Warmup-to-Improve-Deliverability · read 22 October 2026
05
Warmup pauses when credits run out
If the team does not have enough credits when the next cycle is charged, warmup pauses for the mailbox and can be restarted after more credits are added.
knowledge.apollo.io/hc/en-us/articles/26772718460045-Use-Email-Warmup-to-Improve-Deliverability · read 22 October 2026
06
Finish warmup before sending
The help article says to allow warmup to finish before sending automated or manual emails in Apollo.
knowledge.apollo.io/hc/en-us/articles/26772718460045-Use-Email-Warmup-to-Improve-Deliverability · read 22 October 2026
07
Test messages only
Warmup sends system-generated test messages through a private network of inboxes. The article suggests a filter on the subject text wbx to hide them.
knowledge.apollo.io/hc/en-us/articles/26772718460045-Use-Email-Warmup-to-Improve-Deliverability · read 22 October 2026
08
A private network, opted into
The help article says warmup connects you to third-party providers that send from your mailbox to a private network of inboxes, which open and reply. It calls participation optional, and says Apollo does not control or take responsibility for those services.
knowledge.apollo.io/hc/en-us/articles/26772718460045-Use-Email-Warmup-to-Improve-Deliverability · read 22 October 2026
09
Connection requirements
Warmup only works on mailboxes connected to Apollo. Office 365 mailboxes need SMTP AUTH enabled. Gmail can connect with Sign in with Google or an app password, which needs two-factor authentication on Gmail.
knowledge.apollo.io/hc/en-us/articles/26772718460045-Use-Email-Warmup-to-Improve-Deliverability · read 22 October 2026
10
Bulk start and status
You can tick several mailboxes and start warmup at once, or set warmup in a CSV import. Mailbox status shows warmup as active, recommended or completed. The article warns that enrolling several mailboxes at once may slow your outbound volume.
knowledge.apollo.io/hc/en-us/articles/26772718460045-Use-Email-Warmup-to-Improve-Deliverability; https://knowledge.apollo.io/hc/en-us/articles/39530186410125-Manage-Mailboxes-and-Domains-on-Apollo · read 22 October 2026
11
Restarts from zero on a relink
If the mailbox address changes, or you disconnect and reconnect it, warmup restarts from zero. A pause for lack of credits or a connection fault keeps progress, and warmup resumes where it left off.
knowledge.apollo.io/hc/en-us/articles/26772718460045-Use-Email-Warmup-to-Improve-Deliverability · read 22 October 2026
12
Do not delete the warmup mail
Apollo recommends filtering warmup mail on the subject text wbx, not mass-deleting it or marking it spam, which may affect sender reputation. Keeping it also helps if Apollo needs to troubleshoot.
knowledge.apollo.io/hc/en-us/articles/26772718460045-Use-Email-Warmup-to-Improve-Deliverability · read 22 October 2026
13
Dips and damaged reputation
For a new mailbox with a dip, the article says keep warming and troubleshoot, because stopping early may hurt reputation. For an established mailbox, minor swings need no pause. It says warmup may not be enough if reputation is already damaged.
knowledge.apollo.io/hc/en-us/articles/26772718460045-Use-Email-Warmup-to-Improve-Deliverability · read 22 October 2026
14
Timing on the product page
Apollo's deliverability product page says warm-up typically takes a few weeks, depends on the domain, provider and pace, and warns that ramping too fast can hurt a new domain.
apollo.io/product/email-deliverability · read 22 October 2026
What Apollo.io does not say
We looked, and found no statement on these. That is about its published pages only, not about the product.
- A published daily ramp: the pattern is chosen from three names with no numbers for the shape
- Whether warmup places or rescues mail from spam
- Which plans count as "select plans" beyond the price card rows
- How many warmup emails a day Apollo's Progressive pattern sends on a given day
- Whether the Warmbox network includes other Apollo customers' mailboxes
Where the sources disagree
We report each version rather than pick one.
- Apollo's deliverability page says warmup is available for any connected mailbox, while its help article says paid plans typically include 1 mailbox per seat and charge 200 credits for each extra one. We report both.
- Apollo's pricing table lists Deliverability Suite & Email Warmup on Basic and above only, while its warmup help article says free plans pay 200 credits for each linked mailbox, which implies warmup is open to Free. We report both.
- Apollo's deliverability product page says warm-up is available for any connected mailbox, which differs from the help article's per-seat allowance and credit charge. We report both, read 2026-10-22.
The numbers
Only what we could verify.
| Measure | Warmerly | Apollo.io |
|---|---|---|
| Email warmup | Every mailbox on the plan, not metered: threaded warmup emails with automated, quoted replies. | From Basic, through Warmbox.ai per its help article: 1 mailbox per seat typically included, 200 credits for each extra mailbox every 30 days. |
| First day of warmup | 4 a day, per mailbox | You set a minimum, 10 recommended |
| Day 30 of warmup | 50 a day, per mailbox | You set a maximum, 40 recommended, 50 the most |
| Provider caps | Gmail 40, Outlook 30, Zoho 25 | Not stated |
| Reply rate | 0.3 by default, thread depth 3 | 30% recommended, 45% the most |
| Mailboxes warmed on the plan | 1 Free, 5 Starter, 25 Growth, 100 Agency | 1 per seat, extra at 200 credits per 30 days |
| Shortest recommended run | 30 days to full volume | Two weeks |
| Pattern choice | One ramp, set by Warmerly | Progressive, Flat or Randomized |
| End date | None found | You set it, two weeks or more recommended |
| Warmup mail against the sending counter | Separate ramp from campaign caps | Not counted |
| Start sending while warming | Campaign ramp from 3 a day, on by default for young mailboxes | Told to let warmup finish first |
| Daily jitter | 0.85 to 1.15 of the quota | Not stated |
| Warmup stops when | Warmup off, or refused sends (1 a day probe) | Team runs out of credits, or connection fails |
In practice
What it means for you.
Our reading of the facts above. Not a promise, and not the only reasonable reading.
Who sets the volume
Warmerly decides the ramp and tells you why today's limit is what it is. Apollo hands you the dials. If you know what you want, that is useful. If you do not, a set ramp is safer.
Cost grows with mailboxes on Apollo
A team that warms 5 mailboxes with one seat would pay for 4 extra mailboxes at 200 credits each per 30 days, going by the help article.
One warmup tool per mailbox
If you use both tools, turn warmup off in one of them for any shared mailbox.
When each provider reaches its cap
Reading along the ramp's straight lines between anchors, Zoho reaches its 25 a day cap at day 14, Outlook its 30 at about day 18 and Gmail its 40 at about day 24. Only a mailbox with no provider cap, or a custom or Namecheap one at 50, runs to day 30.
Roughly how many warmup sends in 30 days
Adding the area under the straight lines between the anchors gives about 800 warmup sends over days 0 to 30 for one mailbox, before the 0.6 weekend factor and the daily noise. Treat it as an order of magnitude.
What Apollo's range allows in two weeks
At 10 a day for 14 days is 140 warmup emails, and at the recommended maximum of 40 it is 560. The pattern you choose decides where between those a run sits.
Extra mailboxes as a share of credits
Four extra mailboxes at 200 credits is 800 credits per 30 days. Basic's 30,000 credits a year averages 2,500 a month, so that is 32 per cent of it. On Professional's 48,000 a year, which averages 4,000 a month, it is 20 per cent. Those credits are shared with email and phone lookups.
Who it suits
Pick the one that fits.
Warmerly
Warmerly is the better fit if
- You want every mailbox warmed on a set ramp with no credit cost
- You want a named reason for each day's limit
- You want warmup that is already running while a young mailbox sends its first small campaigns
Apollo.io
Apollo.io is the better fit if
- You want to pick a flat or randomised pattern and your own end date
- You already work in Apollo and one mailbox per seat is enough
- You want to set your own daily range, reply rate and end date
Questions
Does Apollo.io include email warmup?
Yes, on Basic and up. Its help article says warmup runs through Warmbox.ai, a third-party provider, and that paid plans typically include warmup for 1 mailbox per seat.
How long does Warmerly take to warm a mailbox?
The ramp reaches 50 a day at day 30. Gmail mailboxes cap at 40, Outlook at 30 and Zoho at 25, so those reach their cap earlier.
Can I send in Apollo while a mailbox is warming?
The help article says to allow warmup to finish before sending automated or manual emails in Apollo. Warmerly's campaign ramp starts a young mailbox at 3 a day, and is on by default when a project's mailboxes have under 14 days of warmup.
Does Apollo's warmup use my sequences?
No. The help article says it sends system-generated test messages between a private network of inboxes, not your sequences, templates or AI-written mail.
What if I run out of Apollo credits?
Apollo pauses warmup for the mailbox rather than cancelling it. After more credits are added you restart it from the mailbox settings, and it resumes where it left off.
Sources
- Apollo help: Use Email Warmup to Improve Deliverability
- Apollo pricing page, rendered in a browser, plus its FAQ
- Apollo email deliverability page
- Warmerly plans and limits (product docs)
- Apollo help: Manage Mailboxes and Domains on Apollo
- Apollo email deliverability product page
Apollo.io 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.
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