Comparison
WarmInboxes vs Coldmail
Coldmail: Google Workspace mailbox provisioning with admin access, monitoring, optional warmup and API/webhook support.
WarmInboxes column checked 2026-10-17 against /price.md, /how-it-works and /offer. Coldmail column: checked 2026-11-11 against its own pages at coldmail.app.
| Criterion | WarmInboxes | Coldmail |
|---|---|---|
| Price | Prewarmed Google or Microsoft $6–$8 per inbox per month by billing cycle, free prewarmed .COM/.CO domain included. Azure tenants $50–$69 per month for up to 100 inboxes. Fresh inboxes on your own domains: Google $2.00–$3.50, Microsoft 365 $2.00–$3.00, Azure tenant $50. (source) | Starter $35/mo for 10 Google inboxes; Growth $97.50/mo for 30; Scale $299/mo for 100. Annual equivalents $20/$60/$199 per month. Warmup add-on $3/mailbox/mo. (source: coldmail.app/pricing) |
| Provider type | Official, licensed Google Workspace, Microsoft 365 and Microsoft Entra (Azure) tenants. Isolated per customer: no shared tenants, you hold admin on every mailbox. (source) | Official Google Workspace; admin console per domain with 2FA. (source: coldmail.app/pricing) |
| Setup time | Delivered within 48 to 72 hours of payment, prewarmed and fresh alike, DNS included. Prewarmed sends the day it lands; fresh after 14 to 21 days of warmup. (source) | Site advertises 10-minute delivery. (source: coldmail.app/pricing) |
| Domain ownership | Prewarmed orders include a prewarmed .COM or .CO domain registered by us; fresh orders run on domains you own or buy through us. The Terms of Service set out the domain term and what cancelling does to it. (source) | Domain ownership/transfer terms not stated on checked pricing page. (source: coldmail.app/pricing) |
| DNS setup | SPF, DKIM, DMARC and forwarding configured before handover and verified by hand against a delivered message, on every platform. (source) | Automated provisioning; DNS record details not stated on checked pricing page. (source: coldmail.app/pricing) |
| Warmup | Prewarmed inboxes arrive already warmed. Fresh inboxes are warmed by our technicians for 14 to 21 days. Once the inboxes are connected to your sequencer, its own warmup is switched on and runs alongside your campaigns, and we switch ours off, so the mailboxes are never warmed by two systems at once. An AI agent sends but does not warm, so tell us the inboxes are going to an agent: we keep them in our warmup pool for free, or you can connect an external warmup tool. (source) | Email warmup $3/mailbox/month add-on. (source: coldmail.app/pricing) |
| API access | REST API at api.warminboxes.com/v1 with read, write and orders:place scopes, a one-file CLI, and a sandbox where test keys run the same routes without charging. Reference published verbatim on this site. (source) | API on Growth/Scale; webhooks on Scale; sandbox not published. (source: coldmail.app/pricing) |
| MCP support | Two MCP servers: a keyless public one exposing every free deliverability check read-only, and an authenticated one on the account that previews and places orders, follows builds and exports into sequencers. (source) | MCP for mailbox ordering not published. (source: coldmail.app/pricing) |
| Sequencer integration | Direct export into Instantly, Smartlead, PlusVibe and EmailBison from the portal or the API; any IMAP/SMTP or OAuth tool from the credentials you hold. (source) | Export-ready mailboxes, integration details not listed. (source: coldmail.app/pricing) |
| Support | 24/7 WhatsApp with operators who run cold email campaigns themselves, plus email. No ticket queue. (source) | Support all tiers, priority on Scale; 24/7 support claimed. (source: coldmail.app/pricing) |
| Replacement policy | The 7-Day Placement Replacement Guarantee. Follow the sending requirements, and if an eligible newly delivered inbox fails our placement standard (warm primary inbox placement) during its first seven days, we replace that inbox at no charge. Send us the evidence (a placement test, bounces or headers) within those seven days and our team assesses it. Placement itself is not guaranteed: the receiving providers make every filtering decision. Replacements after the first week are not free. (source) | Replacement policy not published on pricing page. (source: coldmail.app/pricing) |
| Testing methodology | Published: a dated placement test log with senders and seed accounts, a SURBL blocklist study and a Google sender reputation study by top-level domain, each with sample sizes and what the method cannot see. (source) | Monitoring and inbox placement targets claimed; dates/seed/sample methodology not published. (source: coldmail.app/pricing) |
| Real observations | Our own agency sends more than a million cold emails a month on this infrastructure, and the studies above are drawn from that sending. (source) | Internal outbound sending volume not published. (source: coldmail.app/pricing) |
Where Coldmail may be the better choice
- Lower Google rate on yearly billing; API/webhooks for larger plans.
Verify it yourself: read both pricing pages the same day, put the thirteen questions to their support, and run a ten-inbox thirty-day test on each. All comparisons →