Best cold email infrastructure providers (mailboxes & domains)
Cold email infrastructure tools sell the mailboxes and domains you send from, with SPF, DKIM and DMARC set up for you. They sit underneath a sending tool such as Instantly or Smartlead.
How this list works: Ordered by lowest listed monthly entry price; tools priced per mailbox slot through a calculator are listed last. Pricing verified against vendor pages (latest check ). No placement here is paid. Methodology.
Affiliate links: we may earn a commission; it never affects rankings. Disclosure
| Tool | What it is | Price (vendor-published) | Free plan | Channels |
|---|---|---|---|---|
| InboxKit | Cold email infrastructure: buys and configures Google Workspace and Microsoft 365 mailboxes with automated DNS. | One flat rate per mailbox: $3.00/mailbox/mo monthly or $2.50 annual (Google Workspace or Microsoft 365); Azure $30 per tenant/mo (up to 100 mailboxes); pre-warmed mailboxes $6–$9/mo by warmup age plus a one-time domain fee from $12.50 | — | |
| Zapmail | Cold email infrastructure: pre-configured Google and Microsoft mailboxes with automated SPF, DKIM and DMARC. | Starter $39/mo (10 Google/Microsoft mailboxes, extra $3.50/mailbox); Growth $99/mo (30); Pro $299/mo (100, API) | — | |
| Mission Inbox | Email sending infrastructure with mailboxes on dedicated IPs for cold outreach. | Lite $50/mo (15 mailboxes, 5,000 sends/mo, upgrade required past the limits); Scale $199/mo (30 mailboxes, 10,000 sends/mo, then pay as you go at 1 credit = $1); dedicated IPs on both; the Pro $99/mo API-sending plan shown earlier is no longer listed | — | |
| Maildoso | Low-cost SMTP mailboxes for outbound with IP rotation and self-healing mailboxes. | Monthly SMTP mailboxes: 30 for $75/mo, 300 for $225/mo, 1,000 for $499/mo; quarterly plans with domains from $299/qtr; domains $12/yr ($15 from Oct 1, 2026 per vendor); no discounts | — | |
| Inframail | Flat-rate cold email infrastructure with Microsoft-backed inboxes and automated DNS setup. | Unlimited plan $147/mo (unlimited inboxes, ~80,000 emails/mo); Agency Pack $387/mo; done-for-you setup $797/mo (3-month minimum) | — | |
| Mailreef | Cold email sending infrastructure for agencies, priced as a platform fee plus a per-send rate. | Agency $240/mo with a 12-month commitment, or Agency Flex $249/mo month to month, each plus $0.001 per send; Enterprise custom | — | |
| Mailforge Visit Mailforge ↗ | Creates cold email domains and mailboxes in bulk with automated DNS setup; part of the Salesforge product family. | Shared mailbox infrastructure: $3 per mailbox slot/mo billed yearly (minimum 10 slots; e.g. 25 slots $60/mo yearly or $75/mo monthly); .com domains $14/year; automated DNS setup included | — | |
| Infraforge Visit Infraforge ↗ | Private, dedicated-IP email infrastructure for cold outreach; part of the Salesforge product family. | Calculator-based: mailbox slots $4/mo (billed yearly), .com domains $14/yr; dedicated IPs $99/mo each; no free trial | — | |
| Premium Inboxes | Cold-email inbox provider that sets up and monitors sending inboxes and domains, with auto-reconnect to sequencers. | $3.50 per inbox/mo (1-249 inboxes), $3.00 (250-1,249), $2.80 (1,250+), no monthly commitment; managed ECC service $7,500/mo by application | No | |
| ScaledMail | Cold email infrastructure provider that sets up Google, Microsoft and SMTP mailboxes and domains for outbound. | Priced per unit: Google Workspace $3.50/mailbox/mo; Microsoft Outlook $50/domain/mo (25 mailboxes per domain); SMTP $3.75/domain/mo (4 mailboxes per domain); SPF, DKIM and DMARC configured; reporting add-ons $2–5/mo | — | |
| Hypertide | Automated cold email infrastructure: Google and Microsoft inboxes set up with DNS and uploaded to your sequencer. | Google inboxes $3.30/inbox/mo with no packages or minimums; Microsoft (Entra) domains $25/domain/mo including 25 inboxes ($1 per inbox); automated setup and DNS | — |
FAQ
How much do cold email mailboxes cost?
Published prices in our data: InboxKit $3 per Google or Microsoft mailbox/mo ($2.50 annual) with no minimum, Zapmail $39/mo for 10 Google or Microsoft mailboxes, Mission Inbox $50/mo for 15 mailboxes on dedicated IPs (5,000 sends/mo), Maildoso 30 SMTP mailboxes for $75/mo, Inframail a flat $147/mo for unlimited inboxes, Mailreef $240/mo with a 12-month commitment ($249 month to month) plus $0.001 per send, Mailforge $3 per mailbox slot/mo billed yearly (minimum 10) and Infraforge $4 per slot/mo billed yearly plus $99/mo per dedicated IP. ScaledMail prices per unit: Google Workspace $3.50/mailbox/mo, Microsoft $50/domain/mo (25 mailboxes) and SMTP $3.75/domain/mo. Hypertide charges $3.30 per Google inbox/mo with no minimums, or $25 per Microsoft domain with 25 inboxes.
Shared or dedicated infrastructure?
Mailforge uses a shared IP pool and Infraforge dedicated servers and IPs; both come from the Salesforge family, which recommends Mailforge if you expect many spam reports and Infraforge if you follow deliverability best practices strictly.
Compare tools from this list
- Zapmail vs Mailforge
- Inframail vs Mailforge
- Maildoso vs Zapmail
- Infraforge vs Mailforge
- ScaledMail vs Zapmail
- Mission Inbox vs Mailforge
- Hypertide vs Zapmail
- Hypertide vs ScaledMail
- InboxKit vs Zapmail
- InboxKit vs Mailforge
- Mailreef vs Maildoso
- Premium Inboxes vs Zapmail
- Premium Inboxes vs Mailforge
- Premium Inboxes vs Inframail
Related roundups
- Best Hypertide alternatives: cold email mailbox providers
- Best Inframail alternatives: cold email infrastructure compared
- Best Maildoso alternatives: mailbox and domain providers for cold email
Free weekly newsletter
The SDR List Weekly
One quick email a week on AI sales tools: pricing changes (with sources), new tools worth a look, and one useful comparison. Less tab-hopping, more pipeline.
No spam, unsubscribe anytime. You'll get a quick confirmation email first.