A pre-warmed inbox is a mailbox that has already been through warm-up before you receive it, so you can start sending without the usual two to four week wait. Plenty of providers get listed under this label without selling it. Some sell fresh inboxes you warm yourself, and some sell pre-warmed domains with brand new mailboxes on top.
Below are seven providers that state on their own websites that they sell pre-warmed inboxes: Frostmailer, WarmInboxes, InboxKit, Zapmail, Smartlead, MailDeck and Primeforge. Every competitor figure comes from that provider's own website or help centre, checked on 13 November 2026. Frostmailer prices are in euros, the others in US dollars. Where a provider does not publish a detail, the table says so.
Quick Comparison
| Provider | Pre-warmed platforms | Pre-warmed price | Warm-up stated | Domain | Minimum |
|---|---|---|---|---|---|
| 1. Frostmailer | Azure (Outlook) and Google Workspace | Azure €50 per tenant a month; Google €8 per account a month | 4 weeks, done before delivery | Included on both | 2 tenants on Azure; 6 accounts on Google |
| 2. WarmInboxes | Google Workspace, Microsoft 365 and Azure | Google and Microsoft 365 $8 per inbox a month ($6 on quarterly billing); Azure tenant $69 a month ($50 on quarterly billing) | Ready to send on delivery; length not stated | Pre-warmed .com or .co included on Google and Microsoft 365; not stated for Azure | Packs of 3 inboxes; 1 Azure tenant of 100 inboxes |
| 3. InboxKit | Google Workspace, Microsoft 365 and Azure | Google and Microsoft 365 $6, $7 or $9 per mailbox a month; Azure $30, $40 or $50 per tenant a month | Three tiers: 2 to 4, 4 to 8 and 8+ weeks | One-time fee from $12.50 per pre-warmed domain | Not stated for pre-warmed |
| 4. Zapmail | Google Workspace | Add-on from $6 per mailbox | "Skip 3 to 4 weeks of warmup" | Not clear on the pricing page | Not stated for pre-warmed |
| 5. Smartlead | Not specified | $9 per mailbox a month | Warm-up completed; length not stated | $18 a year | One bundle of 3 mailboxes on one domain |
| 6. MailDeck | Outlook only | $40 per tenant a month | "Skip warmup entirely"; length not stated | Not stated for pre-warmed; standard plans are bring your own | Not stated for pre-warmed; 2 tenants on standard plans |
| 7. Primeforge | Google Workspace and Microsoft 365 | Not published | "Warmup already completed"; length not stated | $14 a year per .com on standard mailboxes | 10 mailbox slots on standard mailboxes |
Pre-warming does not guarantee inbox placement. List quality, message relevance and sending behaviour still decide where your emails land. A pre-warmed inbox removes the waiting period, nothing more.
What to check before you buy
- What exactly was warmed. A pre-warmed domain with a new mailbox on it is not the same as a pre-warmed mailbox. Ask which one you are getting.
- How long it was warmed. Only Frostmailer and InboxKit publish a warm-up length for the inboxes they deliver. For the others, ask for the dates.
- Whether the domain is in the price. It is included at Frostmailer and on WarmInboxes Google and Microsoft 365 packs, and a separate fee at InboxKit, Smartlead and Primeforge.
- The billing unit. Azure is priced per tenant, Google and Microsoft 365 per mailbox. A tenant can hold up to 100 inboxes, so the two prices are not comparable line for line.
- Whether it works in your sending tool. Connect one inbox to your sequencer and test sending and reply sync before you buy the rest.
1. Frostmailer
Frostmailer sells pre-warmed inboxes on both Azure and Google Workspace, with four weeks of warm-up done before delivery and the domain included in the price on both.
A pre-warmed Azure tenant costs €50 a month and comes with one .com domain and your choice of 25, 50 or 100 inboxes for the same price. The minimum order is two tenants. Each tenant sends about 200 emails a day in total, so 50 inboxes per tenant is the recommended density.
Pre-warmed Google accounts cost €8 each a month, with three accounts per domain. The minimum is six accounts, sold in steps of three.
Inboxes connect to EmailBison, Smartlead, Instantly, PlusVibe, Success.ai and MasterInbox. Pre-warmed products are ordered in the app, and support is 24/7.
2. WarmInboxes
WarmInboxes is built around pre-warmed inventory and sells it on three platforms. Pre-warmed Google Workspace and Microsoft 365 inboxes cost $8 each a month on monthly billing, $7 on two-month billing and $6 on quarterly billing. They are sold in packs of three, and each pack includes a pre-warmed .com or .co domain.
Its pre-warmed Azure tenant holds 100 inboxes and costs $69 a month on monthly billing, $60 on two-month billing and $50 on quarterly billing. The site does not say whether the domain is included on the Azure tenant.
Delivery is 48 to 72 hours after payment. Inboxes are described as ready to send on delivery, but the site does not state how long they were warmed. Integrations include Instantly, Smartlead and EmailBison.
Compared with Frostmailer: very similar Google pricing on monthly billing, with a cheaper rate if you commit to a quarter. Frostmailer's pre-warmed Azure tenant is €50 on monthly billing with the domain included, against $69 monthly here.
3. InboxKit
InboxKit is the only provider here that prices pre-warmed inboxes by how long the domain has been warming. Google Workspace and Microsoft 365 mailboxes cost $6 a month for 2 to 4 weeks of warm-up, $7 for 4 to 8 weeks and $9 for 8 weeks or more. Pre-warmed Azure tenants, which hold up to 100 mailboxes, cost $30, $40 and $50 a month on the same three tiers.
Each pre-warmed domain carries a one-time fee starting at $12.50. InboxKit states no minimum order for its standard mailboxes, and does not state one for pre-warmed. It offers a REST API, webhooks and an MCP server.
Compared with Frostmailer: lower entry prices and a choice of warm-up age, with the domain charged on top. Frostmailer has one price per product with four weeks of warm-up and the domain included.
4. Zapmail
Zapmail sells pre-warmed mailboxes as an add-on to its Google Workspace plans. Its pricing page says they let you "skip 3 to 4 weeks of warmup" and start from $6 per mailbox. It does not list the full pre-warmed price table, the minimum order or the domain terms publicly.
For context, Zapmail's standard Google plans cost $39 a month for 10 mailboxes, $99 for 30 and $299 for 100. The pricing page states that Google Workspace mailbox pricing increases after the first year, and Zapmail requires nameservers to stay pointed to Zapmail.
Compared with Frostmailer: a lower starting price per pre-warmed mailbox, with less published detail. Ask for the full pre-warmed price, the domain terms and the year-two price before ordering.
5. Smartlead
Smartlead is a sending platform that also sells pre-warmed mailboxes inside its own product. They cost $9 per mailbox a month, billed monthly, plus $18 a year for the domain, billed annually.
Mailboxes come in fixed bundles of three per domain, and you cannot add more mailboxes to a domain after purchase. Smartlead's help centre says the mailboxes "have already gone through the complete warm-up process" but gives no warm-up length and does not name the mailbox platform. It recommends starting at 20 to 30 emails a day per mailbox and adding five a day.
Compared with Frostmailer: convenient if you already send from Smartlead, at a higher price per mailbox with the domain charged separately. The help centre does not say whether the mailboxes can be used in another sending tool, so ask before you rely on that.
6. MailDeck
MailDeck sells pre-warmed Outlook inboxes at $40 per tenant a month. Its site says they "skip warmup entirely and are ready for cold sending immediately". It does not offer pre-warmed Google inboxes, and says its Google inboxes need at least 15 days of warm-up.
MailDeck's standard Outlook tenants hold 100 inboxes with a two-tenant minimum, and clients bring their own domains. The site does not state the inbox count, minimum order or domain terms for the pre-warmed tenant specifically, or how long it was warmed.
Compared with Frostmailer: $40 against €50 per pre-warmed tenant. Frostmailer includes the domain and publishes the warm-up length. Confirm both with MailDeck before ordering.
7. Primeforge
Primeforge sells Google Workspace and Microsoft 365 mailboxes and lists pre-warmed mailboxes as a product. Its page says "mailboxes arrive with warmup already completed so campaigns can go live without delay".
It does not publish a pre-warmed price, a warm-up length or a pre-warmed minimum. Its standard mailboxes cost $4.50 per slot a month with a 10-slot minimum, and .com domains cost $14 a year.
Compared with Frostmailer: not possible to compare on price until Primeforge quotes one. Request a written quote that states the pre-warmed price, the warm-up length and the domain cost.
Providers often listed that do not sell pre-warmed mailboxes
Two names turn up in pre-warmed roundups without selling a pre-warmed mailbox, going by their own websites on 13 November 2026.
- Maildoso sells SMTP mailboxes on its own servers. It offers pre-warmed domains at $11.99 a month each, but the mailboxes you add to them are new, and its own setup guidance says to warm new mailboxes and domains for at least 14 days.
- Hypertide sells Google inboxes at $3.30 each a month and Entra inboxes at $25 per domain a month. Its site describes a two week warm-up period after setup and does not describe any inbox as pre-warmed.
Both can be a good fit if you are happy to wait out the warm-up. They are just not a way to skip it.
Which provider fits?
| If you want | Look at | Why |
|---|---|---|
| Pre-warmed Azure with the domain in the price | Frostmailer | €50 per tenant, 4 weeks of warm-up, .com included |
| Pre-warmed Google with the domain in the price | Frostmailer or WarmInboxes | €8 and $8 per inbox on monthly billing, domain included on both |
| A choice of warm-up age | InboxKit | Three published tiers from 2 to 4 weeks up to 8+ weeks |
| Pre-warmed Microsoft 365 per mailbox | WarmInboxes or InboxKit | Both publish per-mailbox pre-warmed Microsoft 365 prices |
| To stay inside your sending platform | Smartlead | Bought and used inside Smartlead |
| The lowest published pre-warmed Outlook tenant price | InboxKit or MailDeck | $30 to $50 and $40 per tenant, with domain terms to confirm |
Before a large order, buy the minimum, connect it to your sequencer and send at low volume for a week. Check SPF, DKIM and DMARC in the message headers, and watch bounces and replies before you scale.
FAQs
What is a pre-warmed inbox?
A pre-warmed inbox is a mailbox on a domain that has already been through a warm-up period, usually two to four weeks or more, before it is handed to you. It lets you start cold sending at low volume straight away instead of waiting for a new inbox to build a sending history.
How much do pre-warmed inboxes cost?
On the providers' own websites in November 2026, pre-warmed Google and Microsoft 365 mailboxes cost about $6 to $9 each a month, and pre-warmed Azure or Outlook tenants cost about $30 to $69 a month. Frostmailer charges €8 per pre-warmed Google account and €50 per pre-warmed Azure tenant, with the domain included in both.
Should I keep warming inboxes during active campaigns?
Yes, keep warm-up running during active campaigns. A pre-warmed inbox already has a sending history, but steady warm-up activity alongside your campaign sends helps keep that reputation as you increase volume.
Do pre-warmed inboxes guarantee inbox placement?
No. Pre-warming removes the waiting period. Placement still depends on your list quality, your copy and how quickly you raise sending volume. Start low and increase slowly, even on a pre-warmed inbox.