Comparison
WarmInboxes vs Smartlead
Smartlead: Marketplace for Google, Microsoft and SMTP inboxes, fulfilled by third-party vendors. Where Smartlead's own pages disagree with each other, the row says so rather than picking one.
WarmInboxes column checked 2026-10-17 against /price.md, /how-it-works and /offer. Smartlead column: checked 2026-11-11 against its own pages at helpcenter.smartlead.ai.
| Criterion | WarmInboxes | Smartlead |
|---|---|---|
| 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) | SmartSenders vendor listings: Zapmail Google $4.50/inbox/mo + $13/domain/yr; Zapmail prewarmed $9/inbox/mo + $18/domain/yr; Mailreef SMTP $3.99/inbox/mo. Other help articles list different vendor prices. (source: helpcenter.smartlead.ai/en/articles/266-smartsenders-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) | Marketplace for Google, Microsoft and SMTP inboxes, fulfilled by third-party vendors. (source: helpcenter.smartlead.ai/en/articles/266-smartsenders-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) | Typically 24–48 hours in newer purchasing guide. (source: helpcenter.smartlead.ai/en/articles/266-smartsenders-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) | Domains purchased through SmartSenders; some vendor accounts locked within platform. (source: helpcenter.smartlead.ai/en/articles/266-smartsenders-pricing) |
| DNS setup | SPF, DKIM, DMARC and forwarding configured before handover and verified by hand against a delivered message, on every platform. (source) | Automated domain setup. (source: helpcenter.smartlead.ai/en/articles/266-smartsenders-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) | Smartlead warmup available; prewarmed vendor option. (source: helpcenter.smartlead.ai/en/articles/266-smartsenders-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) | Not published on Smartlead’s own pages when read on 2026-11-11. Ask them: Is there a documented API to order, read build state and export mailboxes, with a sandbox? |
| 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) | Not published on Smartlead’s own pages when read on 2026-11-11. Ask them: Can an AI assistant act on the account through an MCP server, and is the free diagnostic layer reachable without a key? |
| 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) | Direct Smartlead connection. (source: helpcenter.smartlead.ai/en/articles/266-smartsenders-pricing) |
| Support | 24/7 WhatsApp with operators who run cold email campaigns themselves, plus email. No ticket queue. (source) | Smartlead chat/deliverability specialists. (source: helpcenter.smartlead.ai/en/articles/266-smartsenders-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) | Not published on Smartlead’s own pages when read on 2026-11-11. Ask them: What happens when an inbox stops landing: replaced, on what terms, in what time? |
| 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) | SmartDelivery optional placement testing. (source: helpcenter.smartlead.ai/en/articles/266-smartsenders-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) | Not published on Smartlead’s own pages when read on 2026-11-11. Ask them: Does the provider send cold email on this infrastructure themselves, at what volume, and is any of it published? |
Where Smartlead may be the better choice
- Bundled purchasing and sequencing.
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 →