Warmerly
A placement test on up to 4 targets. Accuracy is limited: no dedicated Gmail or Outlook seed list yet.
Warmerly
Apollo.io
One-to-one · Inbox placement checks
Inbox placement checks
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
A placement test on up to 4 targets. Accuracy is limited: no dedicated Gmail or Outlook seed list yet.
Apollo.io
Placement tests to seed mailboxes at the providers you tick, with a score and a folder breakdown. Hotmail, Yahoo and AOL tests are temporarily unavailable.
The short answer
Inbox placement checks, in one look.
Both run a placement test from a mailbox. Warmerly sends one message to up to 4 target mailboxes and scores each result, but its accuracy is limited today because it has no dedicated Gmail or Outlook seed list yet. Apollo sends test emails from your mailbox to seed mailboxes at the providers you tick and shows a score and a breakdown by folder and provider, though its Hotmail, Yahoo and AOL tests are temporarily unavailable. On what is published, Apollo's test is built on real seed mailboxes and Warmerly's is not yet. Last checked 22 October 2026.
Apollo.ioApollo.io ahead on this row
Placement tests to seed mailboxes at the providers you tick, with a score and a folder breakdown. Hotmail, Yahoo and AOL tests are temporarily unavailable.
The picture
Drawn side by side.
How a placement test runs
Step by step, in each tool's own words
WarmerlyApollo.io
Warmerly
Send to up to 4 targetsWait 30 to 90 secondsRead inbox, promotions, spamScore 100, 60, 10 or 0
Apollo.io
Tick the providersSend to seed mailboxesScore and healthFolder and provider breakdown
Warmerly has no dedicated Gmail or Outlook seed list yet, so its test falls back to its own warmup-pool mailboxes and says so in the app. Apollo's article says its results are a diagnostic signal, not an exact percentage, and that Hotmail, Yahoo and AOL tests are temporarily unavailable.
On screen
What it looks like.
WarmerlySample data
How Warmerly does it
Warmerly, in detail.
A test per mailbox that scores where each message lands, with a clear note that accuracy is limited for now.
01
What a test does
It sends one message from the mailbox's own SMTP to up to 4 targets, waits 30 seconds on demand or 90 in the daily sweep, checks INBOX, Promotions, Spam and Junk over IMAP, and scores each: inbox 100, promotions 60, spam 10, missing 0.
Warmerly product, checked 21 October 2026
02
No dedicated seed list yet
Real measurement needs seed mailboxes at Gmail, Outlook or Yahoo. The doc's check on 2026-10-15 found none in production, so every test falls back to Warmerly's own warmup-pool mailboxes.
Warmerly product, checked 21 October 2026
03
Why a degraded result is not a measurement
Warmerly's own mailboxes accept almost everything, so a degraded score is about 100 whatever the sender's real performance. The account page shows a Limited accuracy note.
Warmerly product, checked 21 October 2026
04
Allowances
Monthly placement tests: 3 on Free, 5 on Starter, 25 on Growth and 100 on Agency. The daily sweep tests up to 5 mailboxes per run.
Warmerly product, checked 21 October 2026
05
On demand and daily
A run from the Health tab takes about 45 to 60 seconds. The daily sweep tests up to 5 mailboxes per run and skips any mailbox tested in the last 24 hours. A run left running for over 20 minutes is marked failed.
Warmerly product, checked 21 October 2026
06
A degraded result never changes health
A run that used only Warmerly's own mailboxes is flagged degraded and returns before it writes to health. It is also left out of the spam score and the figure that sets a mailbox's sending quota, so an inflated 100 cannot raise how much a mailbox may send.
Warmerly product, checked 21 October 2026
07
Real seeds: built, off, never run live
A mode that tests against consenting Gmail and Outlook mailboxes of other customers in the warmup network exists but is off by default. It would cap use at 2 tests per customer and 2 per mailbox per rolling 24 hours, read only the Message-ID header, and has not been run against a real Gmail or Outlook mailbox.
Warmerly product, checked 21 October 2026
08
A 30-day inbox guarantee
The published guarantee refunds that month's plan fee if a mailbox warming continuously for 30 days shows no placement improvement between its first test and one on or after day 30. Both tests must run in Warmerly, and there is one refund per workspace.
Warmerly product, checked 21 October 2026
09
Where Warmerly is behind
Apollo's page describes testing against seed mailboxes. Warmerly's real-seed mode is built but switched off, a late-arriving message reads as missing, and Gmail's Promotions tab is not visible over IMAP.
Warmerly product, checked 21 October 2026
How Apollo.io does it
Apollo.io, in detail.
Placement tests run from the mailboxes page, with seed mailboxes per provider and a score.
01
How a test runs
Click Run test beside a mailbox, tick the email providers to include, and confirm. Apollo sends non-promotional test emails from your mailbox to seed mailboxes for each provider you select. No contacts in Apollo are emailed.
knowledge.apollo.io/hc/en-us/articles/39530186410125-Manage-Mailboxes-and-Domains-on-Apollo · read 21 October 2026
02
What you get back
A score and a health of Healthy, Caution, Unhealthy or Failed, with a breakdown of where each test email landed by folder and provider. The article says to use results as a diagnostic signal, not the exact percentage reaching prospects.
knowledge.apollo.io/hc/en-us/articles/39530186410125-Manage-Mailboxes-and-Domains-on-Apollo · read 21 October 2026
03
Some providers are paused
The article says Hotmail, Yahoo and AOL inbox placement tests are temporarily unavailable, and that Gmail availability may vary while Apollo improves the tests.
knowledge.apollo.io/hc/en-us/articles/39530186410125-Manage-Mailboxes-and-Domains-on-Apollo · read 21 October 2026
04
Run by a third party
Blocklist checks and inbox placement tests are conducted through third-party providers, and participation is optional.
knowledge.apollo.io/hc/en-us/articles/39530186410125-Manage-Mailboxes-and-Domains-on-Apollo · read 21 October 2026
05
Cost and capacity
The article says placement tests do not consume credits but count toward the mailbox's rolling 24-hour sent total.
knowledge.apollo.io/hc/en-us/articles/39530186410125-Manage-Mailboxes-and-Domains-on-Apollo · read 21 October 2026
06
The marketing line
The deliverability page says Apollo lets you track inbox placement, bounce and spam trends, without explaining how placement is measured.
apollo.io/email-deliverability · read 21 October 2026
07
Headline figures, vendor-reported
The deliverability page quotes 94% email deliverability on a cold list, a 45% open rate and a 2.37% cold-to-meeting rate, and says they were benchmarked by the Tolly Group. The page gives no method and we did not check the source.
apollo.io/email-deliverability · read 22 October 2026
08
What the page says it tracks
It says Apollo tracks inbox placement, bounce and spam trends and domain and mailbox health across the team. It does not say how placement is measured.
apollo.io/email-deliverability · read 22 October 2026
09
Which plans list the tools
Basic ($49 per seat per month, billed annually), Professional ($79) and Organization ($119, minimum 3 seats) list the Deliverability Suite & Email Warmup. The Free card does not.
apollo.io/pricing · 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.
- How many seed mailboxes a test uses
- How often tests run unless you run one
- A monthly allowance of tests
- Whether the test results are kept as a history you can compare over time
- Which seed mailbox providers are active today beyond the paused ones named
Where the sources disagree
We report each version rather than pick one.
- Apollo's mailboxes article says placement tests do not consume credits, while its credit usage article lists inbox placement tests among email infrastructure credit uses. We report both.
- Apollo's pricing page FAQ names the plans Free, Basic, Professional and Custom, while the rendered price cards show Organization ($119, minimum 3 seats). Both were read on 2026-10-22.
- Apollo's deliverability page quotes 94% deliverability and says Tolly Group benchmarked it, while its own help article says test results are a diagnostic signal and not the exact percentage reaching prospects. They answer different questions, and we report both.
The numbers
Only what we could verify.
| Measure | Warmerly | Apollo.io |
|---|---|---|
| Inbox placement checks | A placement test on up to 4 targets. Accuracy is limited: no dedicated Gmail or Outlook seed list yet. | Placement tests to seed mailboxes at the providers you tick, with a score and a folder breakdown. Hotmail, Yahoo and AOL tests are temporarily unavailable. |
| Targets per test | Up to 4 | Seed mailboxes per provider you tick |
| Score for a message in the inbox | 100 | Not stated |
| Score for a message in spam | 10 | Not stated |
| Tests a month on the entry paid plan | 5 | Not stated |
| Real Gmail or Outlook seeds | Not yet | Described, Hotmail, Yahoo and AOL paused |
| Targets by provider | 2 same provider and 2 other | Providers you tick |
| Tests a month on Agency | 100 | Not stated |
| Automatic tests | Daily, up to 5 mailboxes a run | Only when you run one |
| Counts toward sent total | Not stated | Yes, rolling 24 hours |
In practice
What it means for you.
Our reading of the facts above. Not a promise, and not the only reasonable reading.
Treat both as signals
Apollo's own article says its results are a diagnostic signal, not an exact percentage. Warmerly's note says the same, more firmly.
Use the test that has real seeds
Until Warmerly has a seed list at Gmail and Outlook, a placement test from Apollo or a dedicated placement tool tells you more about those providers.
Reading a score
With four targets landing as inbox, inbox, promotions and spam, Warmerly's score is (100 + 100 + 60 + 10) / 4 = 67.5. One spam result among four moves the average by 22.5 points, so read the dots as well as the number.
How far an allowance goes
Starter has 5 tests a month, enough to test 5 mailboxes once each. Growth has 25 and Agency 100. The daily sweep can add up to 5 x 30 = 150 automatic tests a month, which do not use your allowance, but while they use Warmerly's own mailboxes they are limited-accuracy checks.
Apollo's test and your sending cap
The article says a placement test counts toward the mailbox's rolling 24-hour sent total. It does not say how many seed emails a test sends, so the share of a 200-a-day bought mailbox cap that it uses cannot be worked out from the pages we read.
Who it suits
Pick the one that fits.
Warmerly
Warmerly is the better fit if
- You want a quick placement check built in with a plain accuracy warning
- You want the test allowance written out per plan, with failed tests handed back
Apollo.io
Apollo.io is the better fit if
- You want tests against seed mailboxes with a provider breakdown
- You want a score with a folder and provider breakdown across the providers that are available
Questions
Does Apollo.io test inbox placement?
Yes. A test sends from your mailbox to seed mailboxes at the providers you select and shows a score and a breakdown by folder and provider. Some provider tests are temporarily unavailable.
How accurate is Warmerly's placement test?
Limited for now. It has no dedicated Gmail or Outlook seed list yet, so tests fall back to its own warmup-pool mailboxes, and the app says so.
How many placement tests do I get with Warmerly?
3 a month on Free, 5 on Starter, 25 on Growth and 100 on Agency, counted from the 1st. A test that fails to run is not counted.
Does an Apollo placement test email my contacts?
No. Apollo's article says the test emails go to seed mailboxes and no contacts in Apollo are emailed.
Sources
- Apollo help: Manage Mailboxes and Domains on Apollo
- Apollo help: Review Credit Usage in Apollo
- Apollo email deliverability page
- Warmerly plans and limits (product docs)
- Apollo pricing page and FAQ
- Warmerly help: How do inbox placement tests work
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.
Connect a mailbox. Warmerly runs alongside whatever you send from now, so you can compare before you move anything.
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