Azure tenants: the cheapest way to run mailbox density at scale
Dedicated Azure tenant per domain with up to 100 mailboxes — $0.25 effective per mailbox at full density. Built for high-volume senders who understand the trade-offs.
The economics
$25 per domain, divided by 100 mailboxes, is $0.25 per mailbox — one tenth of standard pricing. Math works when you have huge TAM, aggressive A/B testing, or a stage of growth where volume is the priority and per-mailbox cost dominates the spreadsheet.
The trade-off, honestly
Concentration risk: 100 mailboxes share one domain's fate. If that domain gets flagged, all 100 are affected at once. We recommend Azure as a volume layer alongside isolated Google Workspace / M365 for your core, must-deliver campaigns — not as a wholesale replacement.
Enterprise-grade tenancy
Dedicated Azure tenant per domain, not shared. Full Microsoft Graph API access. Real M365 mailboxes underneath — not a fragile workaround.
InboxKit Azure $30/domain · Icemail $30/domain · CLAYINBOX $25/domain
Common questions
More from the platform
Official M365 accounts with automated DKIM via Exchange Online, OAuth exports, and no 'Microsoft premium' pricing. The right tool when your list is full of Outlook inboxes.
Real Workspace accounts with full admin access, automated DNS, isolated one-domain workspaces, and free warmup — at less than a third of Google's retail price.
Three layers of monitoring on every mailbox — continuous blacklist scans across 50+ RBLs, DNS drift detection, unlimited placement tests. Free, not gated.