Inbox-ready mailboxes in minutes. Everything included.
US-IP Google Workspace and Microsoft 365 mailboxes with automated SPF, DKIM, and DMARC — plus warmup, monitoring, free replacements, and a unified inbox bundled in. One flat price: $2.50/mailbox. No platform fee. No add-ons. No tiers.
- ✓Ready to send in 30 min
- ✓US & EU IPs
- ✓Warmup included
- ✓Cancel anytime
Actual setup flow. No DNS spreadsheets, no support tickets.
Plugs into every major sending platform
From domain to inbox in three steps.
Spin up hundreds of sending-ready mailboxes without touching a DNS record.
Connect or buy domains
Bring your own domains or buy fresh ones in seconds. The AI domain finder suggests available, brand-safe alternates for any keyword — and every domain gets its own isolated workspace.
Provision mailboxes in bulk
Choose Google Workspace, Microsoft 365, Azure, or dedicated SMTP. AI autofill generates realistic sender names and profile photos at scale. SPF, DKIM, and DMARC configure themselves.
Export anywhere in one click
Push warmed, ready-to-send mailboxes to Instantly, Smartlead, lemlist, EmailBison, or any sequencer — credentials, app passwords, and custom tracking domains included.
Every provider. One dashboard.
Match your sending infrastructure to your prospects' inboxes — Google to Google, Microsoft to Microsoft.
Google Workspace
$2.50 / mo per mailbox
- Real US-IP Workspace accounts with full admin access
- Pre-warmed mailboxes available ($4.50/mo)
- One isolated workspace per domain
Microsoft 365
$2.50 / mo per mailbox
- Official M365 accounts, no Microsoft premium
- Automated DKIM via Exchange Online
- OAuth + app-password export support
Azure Inboxes
$25 / domain
- Up to 100 mailboxes per domain on dedicated Azure tenants
- Enterprise-grade reputation isolation
- The cheapest path to high mailbox density
Dedicated IMAP/SMTP
$45 / 2 domains
- Dedicated IP and server, 10 mailboxes per domain
- 500 emails / domain / day capacity
- Full SMTP credentials, works with any tool
Features competitors sell as add-ons. We just include them.
01 / Module
Automated SPF, DKIM & DMARC
Every domain is authenticated automatically with best-practice records the moment it's connected. Verified live, before your first send.
02 / Module
Warmup included free
Every mailbox warms on an isolated, reputation-safe network — no shared spam pools. Competitors charge $3–5/mo extra for this. We don't.
03 / Module
Pre-warmed mailboxes
Need to send today? Get mailboxes with established sending history and skip the 14–21 day ramp entirely.
04 / Module
Free unlimited replacements
If a mailbox gets flagged or banned, we replace it instantly at no cost. Forever. No tickets, no fees.
05 / Module
Unified master inbox
Read and reply across every mailbox and every domain from one screen. Stop logging into 200 accounts.
06 / Module
Deliverability monitoring
Blacklist monitoring, DNS drift alerts, and inbox placement tests run continuously on every domain — included on every plan.
07 / Module
Domain isolation by default
One dedicated workspace per domain. A problem on one domain can never cascade into the rest of your infrastructure.
08 / Module
AI domain & identity generator
Drop a keyword and get available, brand-safe domain suggestions, realistic sender names, and profile photos — generated in bulk.
09 / Module
Bulk everything
Create, rename, re-photo, and export hundreds of mailboxes in one action. Update sending limits and signatures across your fleet at once.
10 / Module
US & EU IP infrastructure
Accounts provisioned on clean US or EU IP space for stronger sender reputation and better regional placement.
11 / Module
Custom tracking domains
Per-domain tracking subdomains configured and verified automatically — no CNAME copy-pasting.
12 / Module
Weekly health reports
Bounce rates, reply rates, placement scores, and reputation trends delivered to your inbox every Monday.
Know your infrastructure is healthy before your reply rate tells you it isn't.
- ✓Blacklist monitoring across 50+ RBLs
- ✓DNS record drift detection with instant alerts
- ✓Unlimited inbox placement tests
- ✓Per-mailbox metrics: bounces, replies, soft vs. hard fails
Monitoring suites cost $30–50/mo elsewhere — or simply don't exist. Here it's free on every account.
Headless infrastructure for AI SDRs and SaaS platforms.
Provision domains, create mailboxes, rotate identities, and pull deliverability data programmatically.
- REST API with 70+ endpoints and full webhook support
- Native MCP server — manage your entire infrastructure from Claude, Cursor, or any MCP client
- Bulk operations: provision 500 mailboxes in a single call
- Per-workspace API keys with scoped permissions
POST /v1/mailboxes/bulk
{
"domain": "acme-outreach.com",
"provider": "google_workspace",
"count": 25,
"identities": "ai_generate",
"export_to": "smartlead"
}
→ 201 Created · 25 mailboxes · warmup: startedWorks with the tools you already send from.
One-click export with credentials, app passwords, and tracking domains included. SMTP/IMAP works with everything else.
CLAYINBOX vs. Zapmail vs. Icemail vs. InboxKit.
Same category, very different bills. Here's the line-by-line.
- CLAYINBOX
- $0 — pay per mailbox
- Zapmail
- $39–$299/mo tiers
- Icemail
- $0
- InboxKit
- $39–$299/mo tiers
- CLAYINBOX
- $2.50 flat
- Zapmail
- $3.00–$3.50 / extra
- Icemail
- $2.50
- InboxKit
- $2.50 (annual Ent.) – $3.50
- CLAYINBOX
- ✓same price
- Zapmail
- ✓
- Icemail
- ✓
- InboxKit
- ✓
- CLAYINBOX
- ✓$25/domain · 100 boxes
- Zapmail
- ✗
- Icemail
- $30/domain
- InboxKit
- $30/tenant
- CLAYINBOX
- ✓
- Zapmail
- ✗
- Icemail
- ✓
- InboxKit
- ✗
- CLAYINBOX
- Included free, isolated
- Zapmail
- Paid add-on
- Icemail
- Via pre-warmed tier
- InboxKit
- $3/mo add-on
- CLAYINBOX
- ✓
- Zapmail
- ✓extra cost
- Icemail
- ✓$5/mo
- InboxKit
- ✗
- CLAYINBOX
- Free, unlimited
- Zapmail
- Paid
- Icemail
- Free
- InboxKit
- Limited
- CLAYINBOX
- ✓
- Zapmail
- ✗
- Icemail
- ✓
- InboxKit
- ✗
- CLAYINBOX
- ✓included
- Zapmail
- ✗
- Icemail
- ✗
- InboxKit
- ✓plan-gated
- CLAYINBOX
- ✓unlimited, free
- Zapmail
- ✗
- Icemail
- ✗
- InboxKit
- ✓
- CLAYINBOX
- ✓per-domain workspace
- Zapmail
- ✓
- Icemail
- ✓
- InboxKit
- ✓
- CLAYINBOX
- ✓
- Zapmail
- ✓
- Icemail
- ✓
- InboxKit
- Partial
- CLAYINBOX
- ✓all accounts + MCP
- Zapmail
- Pro plan only ($299/mo)
- Icemail
- ✓
- InboxKit
- ✓
- CLAYINBOX
- ✓
- Zapmail
- ✗
- Icemail
- ✓
- InboxKit
- ✗
Competitor pricing and features as published on their websites, June 2026. We keep this honest — tell us if something changed.
One flat price. Do the math yourself.
No subscriptions. No tiers. No "contact sales." Pay per mailbox, cancel anytime.
Google Workspace
$2.50
/ mailbox / mo
Microsoft 365
$2.50
/ mailbox / mo
Azure Inboxes
$25
/ domain · 100 boxes
Dedicated SMTP
$45
/ 2 domains · 20 boxes
What's included on every account
- ✓Automated DNS
- ✓Warmup
- ✓Monitoring
- ✓Unified inbox
- ✓Free replacements
- ✓Unlimited exports
- ✓API + MCP
- ✓Live chat support
Domains from $13/yr (.com) — or connect your own free. Cloudflare-managed DNS.
0+
Mailboxes provisioned
0+
Domains managed
0.7%
Avg. inbox placement
0 min
Avg. setup time
Agencies run their entire sending layer on CLAYINBOX.
"We migrated 400 mailboxes from a tiered provider and our infra bill dropped 38% — with warmup and monitoring now free."
"Banned mailbox at 9am, replacement live by 9:04. No ticket. That alone is worth the switch."
"The MCP server is unreal. Our AI SDR provisions its own mailboxes when a campaign scales."
"Placement tests caught a DNS drift before it torched a client domain. The monitoring pays for itself — except it's free."
"Setup genuinely took under 30 minutes for 3 domains and 24 mailboxes, DKIM and all."
"Unified inbox means my VA replies across 60 mailboxes from one screen."
// Whitelabel
Resell infrastructure under your own brand.
Your logo, your domain, your pricing — our infrastructure underneath. Client workspaces stay fully isolated, and you set your own margins.
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Refer agencies and founders, earn a cut of every invoice forever. Real-time dashboard, monthly payouts, no caps.
Join the program →Everything people ask before switching.
Free deliverability tools — no signup required
Your next campaign deserves infrastructure that just works.
Mailboxes live in 30 minutes. Everything included. Cancel anytime.
No platform fee · No setup fee · No lock-in