ScaledMail vs MailWarm.io: Which Email Warmup Tool Should You Use?

A brand-new email inbox has zero sending history, and providers like Gmail and Outlook treat that as suspicious by default — send too many cold emails from it too fast and you land in spam before anyone reads a word. 'Warming up' an inbox means sending a gradually increasing volume of emails that get opened, replied to, and marked as not-spam, so the provider learns to trust it. ScaledMail and MailWarm.io both solve this, but for different situations: one sets up and pre-warms inboxes for you from scratch, the other warms up inboxes you already own.

ScaledMail — provisioning and pre-warming inboxes at scale

ScaledMail sets up and pre-warms dozens of email inboxes for cold outreach so a sales team can start sending on day one instead of spending two or more weeks building sender reputation from zero. It handles DNS configuration (SPF/DKIM/DMARC) as part of setup and integrates directly with sequencing tools like Smartlead, Instantly, Apollo, and Lemlist.

Pricing: Google Workspace $3.50/inbox/month · Microsoft 365 $50/domain/month (25 inboxes) · SMTP $3.75/domain/month. A team sending ~2,000 emails/day across providers runs roughly $650/month. Setup takes 24–72 hours.

Best for: agencies and B2B sales teams running cold email at real volume across multiple clients or campaigns, who'd rather pay to skip the setup and warmup period entirely.

MailWarm.io — warming up the inboxes you already have

MailWarm.io improves inbox delivery rates for existing cold-email inboxes by rebuilding sender reputation through a network across 10+ providers (Gmail, Outlook, Yahoo, ProtonMail, and others). It advertises real human engagement with warmup emails rather than pure bot traffic.

Pricing: Free (1 inbox) · Basic $90/year (50 inboxes, 40 emails/day) · Pro $190/year (unlimited inboxes, 80 emails/day) · 20% discount for annual billing.

Best for: individuals, founders, and small teams who already have their sending inboxes set up and just need to build or maintain reputation — at a fraction of ScaledMail's cost, since you're not paying for inbox provisioning or DNS setup.

Verdict

Pick ScaledMail if you need dozens of new inboxes provisioned, configured, and pre-warmed fast because a sales team is waiting to start sending — you're paying for speed and done-for-you setup, not just the warmup itself. Pick MailWarm.io if you already have your inboxes and domains set up and just need an affordable way to keep sender reputation healthy — its annual pricing ($90–$190/year) is dramatically cheaper than ScaledMail's per-inbox monthly model for anyone not running an agency-scale operation.

One honest caveat on MailWarm.io specifically: its name is nearly identical to mailwarm.com (Mailwarm), a separate, unrelated competitor — double-check the domain before signing up. And for either tool, warmup only fixes sender reputation; it won't rescue a list full of bad email addresses or a message that reads like spam.