Warmerly
Not published.
Warmerly
Warmup Inbox
One-to-one · Warmup network size
Warmup network size
One row, in depth: what each tool does, the verified numbers, and who each suits.
Warmup Inbox details read from its pricing page, home page, product pages, API page, integrations pages, help centre, legal pages and status page on 21 October 2026.
Warmerly
Not published.
Warmup Inbox
30,000+ real inboxes, from paying customers and company-run inboxes; 6 million warmup emails a day, as stated.
The short answer
Warmup network size, in one look.
Warmup Inbox states a network of 30,000+ real inboxes and 6 million warmup emails a day, and says the inboxes belong to paying customers and to domains it runs itself. Warmerly does not publish a network size, and its network is smaller than the figure Warmup Inbox states. On what each publishes, Warmup Inbox is ahead on size. Size is not the same as quality, and neither company shows how many of its inboxes are active, aged or healthy. Last checked 21 October 2026.
Warmup InboxWarmup Inbox ahead on this row
30,000+ real inboxes, from paying customers and company-run inboxes; 6 million warmup emails a day, as stated.
The picture
Drawn side by side.
How Warmerly does it
Warmerly, in detail.
A peer pool of real mailboxes, including other customers', paired by load, provider mix and how each recipient's domain has treated the sender. No size is published.
01
No published size
We do not publish a network size, so none is drawn here, and the network is smaller than the figure Warmup Inbox states. We would rather leave the number out than give one we cannot show a method for.
Warmerly product, checked 21 October 2026
02
Who is in the pool
Warmup mail is real mail between mailboxes in one pool. The Warmup Network Participation Terms say the pool includes other customers' mailboxes and may include mailboxes Warmerly hosts or operates itself.
Warmerly product, checked 21 October 2026
03
How a recipient is picked
The planner weights spread of load, provider diversity, the recipient's own quota and how that recipient's domain has treated this sender's mail over the last 14 days. A sender does not write to the same recipient twice within 72 hours.
Warmerly product, checked 21 October 2026
04
Mailboxes that never show the mail are dropped
Recipients whose warmup mail is almost never found, under 20 per cent of at least 20 jobs in 7 days, stop receiving until their evidence ages out. These are called black holes in the code.
Warmerly product, checked 21 October 2026
05
What the recipient does
About 90 per cent of warmup mail is opened after a delay of 10 to 120 minutes, and about 20 per cent of opened mail is starred as important. The recipient replies with a default chance of 0.3 for a first message, lower deeper in a thread, stopping at depth 3.
Warmerly product, checked 21 October 2026
06
Threaded replies, quoted
A reply sets In-Reply-To and References to the original message and quotes it, so providers see one conversation. The attribution line reads On Mon, Oct 5, 2026: and does not name the sender or end in wrote:, as most mail clients do.
Warmerly product, checked 21 October 2026
How Warmup Inbox does it
Warmup Inbox, in detail.
A stated 30,000+ real inboxes, drawn from paying customers and from inboxes the company manages, audited weekly, exchanging 6 million warmup emails a day.
01
30,000+ real inboxes
The home page, FAQ and pricing page each state 30,000+ (the pricing card says more than 30K). The home page adds 25+ providers, Gmail to Outlook, and real opens, replies and mark-as-not-spam.
warmupinbox.com · read 21 October 2026
02
Who owns the inboxes
A help article says the network keeps at least 30,000 active inboxes so a new connection has enough reputable domains to interact with for the life of the subscription. It says they come from paying customers and from domains and inboxes the company manages for warming only.
help.warmupinbox.com/en/articles/4738907-how-many-inboxes-do-you-have · read 21 October 2026
03
Audited weekly
The email warmup page says each inbox is a real account with real conversation history, no bots and no auto-generated personas, and that the network is audited weekly, with stale or low-engagement accounts removed. It lists Gmail, Outlook, Yahoo, Workspace, Microsoft 365 and Zoho.
warmupinbox.com/product/email-warmup · read 21 October 2026
04
6 million warmup emails a day
The home page numbers section gives 30 K real inboxes, 34 % reply rate, 6 M warmup emails daily and 60 s average setup time. By our arithmetic 6 million a day over 30,000 inboxes is 200 a day per network inbox, if the two figures describe the same set.
warmupinbox.com · read 21 October 2026
05
How the content is written
The language warmup page says conversations are AI-generated and then audited by human staff before going to the network, and that providers see authentic exchanges. The home page calls them real human inboxes.
warmupinbox.com/product/language-warmup · read 21 October 2026
06
A claim about other networks
The home page says typical warmup networks are shared pools of fake mailboxes with scripted engagement and recycled domains, and attributes a 15% Primary gain to the difference. It labels the supporting figures an internal benchmark and gives no named competitor.
warmupinbox.com · read 21 October 2026
07
Its own view of two rivals
Its Mailwarm page says Mailwarm claims 50,000+ real aged inboxes and describes its own network as 30,000+ curated and verified real inboxes, including customer inboxes and internal warming inboxes. Newly connected inboxes get test emails and are admitted only if they can receive and keep them.
warmupinbox.com/mailwarm-alternative · read 21 October 2026
What Warmup Inbox does not say
We looked, and found no statement on these. That is about its published pages only, not about the product.
- How the 30,000 splits between customer inboxes and company-run inboxes
- How many of the 30,000 are active on a given day, and what active means
- The age of the domains behind the inboxes, which is how it frames the quality of other networks
- Any consent terms for customers whose inboxes join the pool, on the pages we read
- A figure for network inboxes at each provider, though it lists 25+ providers
- A method for the 15% Primary gain, 98% placement or 34% reply rate on the home page
Where the sources disagree
We report each version rather than pick one.
- The pricing page says more than 30K real inboxes, the help centre says 30,000+ active inboxes at any time, and the Mailwarm page says 30,000+ curated and verified inboxes. The wording changes but the number is the same.
- The home page calls them real human inboxes, and the language warmup page says the conversations they carry are AI-generated and audited by human staff.
- The home page compares itself with typical networks of fake mailboxes without naming any, and its own Mailwarm page says Mailwarm claims 50,000+ real aged inboxes.
The numbers
Only what we could verify.
| Measure | Warmerly | Warmup Inbox |
|---|---|---|
| Warmup network size | Not published. | 30,000+ real inboxes, from paying customers and company-run inboxes; 6 million warmup emails a day, as stated. |
| Stated network size | Not published | 30,000+ real inboxes |
| Warmup emails a day, whole network | Not published | 6 million a day, as stated |
| Per network inbox, arithmetic | Not published | 200 a day if both figures are current |
| Who the inboxes belong to | Other customers' mailboxes, may include Warmerly-run mailboxes | Paying customers and company-managed inboxes |
| Providers named | Gmail, Outlook, Zoho and others by pairing | 25+ providers |
| Repeat contact rule | Same recipient not within 72 hours | Not stated |
| Quality control | Recipients under 20 per cent found over 20 jobs are dropped | Audited weekly, stale accounts removed |
| Content of warmup mail | Threaded replies between pool mailboxes, quoted | AI-generated, audited by human staff |
In practice
What it means for you.
Our reading of the facts above. Not a promise, and not the only reasonable reading.
Size is a stated figure, not a measured one
30,000+ is a company statement, and its own help article does not say how many of the 30,000 are customer inboxes. For a warm-up network, the number of distinct partners matters most when your mailbox needs many different recipients, which a large pool covers more easily.
The pool is also a risk
A big shared pool includes mailboxes you do not control, and every mailbox in it sends and receives warmup mail on your behalf. Both companies use customer mailboxes. If a participation term matters to you, read Warmerly's Warmup Network Participation Terms and ask Warmup Inbox for its own.
Our smaller network has limits you should know
With a smaller pool, the no-repeat rule can run short: a sender doing N a day needs about 3N partners, and the window relaxes to 48 then 24 hours when it does. That is a real cost of a smaller network, and we state it.
Real mailboxes either way
Both describe mail between real mailboxes. Warmup Inbox adds that content is AI-generated and audited by people. Warmerly's replies are quoted threads between pool mailboxes. Providers cannot see which, so the useful question is whether the engagement is healthy and varied.
Ask for evidence either way
If network size is your deciding factor, ask each company for the number of active inboxes at your recipients' providers, and the share that are customer-owned. We would want the same answers from ourselves.
Who it suits
Pick the one that fits.
Warmerly
Warmerly is the better fit if
- You are happy with a smaller network and a published pairing method
- You want to read how recipients are chosen and which are dropped
- You do not need a headline number to decide
- You want warmup between real mailboxes with quoted replies
- You would rather a company say it is smaller than leave it unsaid
Warmup Inbox
Warmup Inbox is the better fit if
- A larger stated network of 30,000+ inboxes decides it for you
- You want a network that includes company-managed inboxes beside customers
- You want the audit claim: weekly checks and stale accounts removed
- You warm many inboxes that need many different partners
- You want a stated provider spread of 25+ providers
Questions
How big is Warmup Inbox's network?
It states 30,000+ real inboxes and 6 million warmup emails a day. Our arithmetic on those two figures is 200 a day per inbox.
Does Warmerly publish its network size?
No, and its network is smaller than the figure Warmup Inbox states. Neither company shows how many inboxes are active or aged.
What stops Warmerly repeating the same contact?
The same recipient is not used within 72 hours, and recipients under 20 per cent found over 20 jobs are dropped.
What is the warmup mail like?
Warmerly sends threaded replies between pool mailboxes. Warmup Inbox says its mail is AI-generated and audited by staff.
Sources
- Warmup Inbox home page
- Warmup Inbox email warmup page
- Warmup Inbox language warmup page
- Warmup Inbox help centre, how many inboxes
- Warmup Inbox compared with Mailwarm (its own page)
- Warmerly warmup network terms
Warmup Inbox 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
- All features
- Starting price (per month)
- Cost at 5 and 25 mailboxes
- Free plan or trial
- What each tier adds
- Warm-up volume per mailbox
- Spam rescue
- Languages, templates and ESP targeting
- SPF, DKIM, DMARC and blocklists
- Placement test
- Supported mailboxes and sign-in
- Campaign sending
- API access
- Agency and client workspaces
- Data, support and terms
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.