Warmup Inbox vs MailWarm (2026): Per-Inbox Pricing vs Flat-Rate Warmup

Warmup Inbox charges by the mailbox: $15 to $79 per inbox a month. MailWarm charges a flat annual fee that covers up to 50 mailboxes on its cheapest plan and unlimited mailboxes on Pro. For a solo founder running two or three sending accounts, that gap barely matters. For an agency running 20+ inboxes across client campaigns, it's the difference between a $190 yearly bill and one north of $3,600.

Warmup Inbox vs MailWarm: 2026 Pricing and Feature Comparison

Tool	Plan	Price	Daily Warmup Volume	Standout Feature
Warmup Inbox	Basic	$15/inbox/mo ($180/yr)	75 emails/day	Access to 30,000+ real inboxes for reply simulation
Warmup Inbox	Pro	$49/inbox/mo ($588/yr)	250 emails/day	AI-generated warmup content plus ESP-specific warmup
Warmup Inbox	Max	$79/inbox/mo ($948/yr)	1,000 emails/day	Unlimited API access and premium support
MailWarm	Basic	$90/yr flat (50 inboxes)	Up to 40 emails/day	50 mailboxes on one flat annual invoice
MailWarm	Pro	$190/yr flat (unlimited inboxes)	Up to 80 emails/day	Unlimited mailboxes with no per-seat math
MailWarm	Free	$0	1 inbox	Ongoing free tier, not a time-boxed trial

How much does Warmup Inbox cost once you're running 20 mailboxes?

At Warmup Inbox's $15/inbox/mo Basic rate, 20 mailboxes run $300/mo, or $3,600/yr. MailWarm's $190/yr Pro plan covers unlimited mailboxes for less than one month of Warmup Inbox Basic at that volume. Below 5 inboxes the gap narrows. Above 10, it becomes the whole decision.

Inboxes warmed	Warmup Inbox Basic ($15/inbox/mo)	MailWarm Pro ($190/yr flat)
5	$75/mo ($900/yr)	$190/yr
20	$300/mo ($3,600/yr)	$190/yr
50	$750/mo ($9,000/yr)	$190/yr

Which tool actually warms up better, not just cheaper?

Price isn't the whole story. Warmup Inbox pushes up to 1,000 messages a day on its Max plan against a pool of 30,000+ real inboxes, with AI-generated content and ESP-specific warmup logic MailWarm doesn't offer, per Warmup Inbox's pricing page. MailWarm tops out at 80 emails a day even on Pro, per MailWarm's own plan details.

Where each one earns its price:

• AI-generated warmup content that varies subject lines and body copy automatically
• ESP-specific warmup tuned separately to Gmail, Outlook, and other providers
• Language warmup for non-English sending domains
• Up to 1,000 messages/day on Warmup Inbox's Max plan

• Flat annual pricing on MailWarm Pro regardless of inbox count
• A genuinely free tier for 1 inbox, not a time-boxed trial
• P2P warmup network with human review built into every plan

Warmup Inbox or MailWarm: which should you actually run?

If you're warming 5 inboxes or fewer and want the most warmup horsepower per mailbox, Warmup Inbox's Basic or Pro tier is worth the per-seat price. Once you cross 10 to 15 inboxes, which is normal for any agency running client campaigns on Smartlead or Instantly, MailWarm's flat pricing wins on cost alone. Its lower daily volume cap is rarely the bottleneck. Deliverability that never gets pushed past 80 sends a day still works for most cold email volumes. Warmup Inbox is the better buy for a handful of high-value inboxes. MailWarm is the better buy for a growing agency stack.

Frequently asked questions

Is MailWarm cheaper than Warmup Inbox?

Yes, for anyone running more than about 6 to 8 mailboxes. MailWarm's Pro plan is $190 a year flat for unlimited inboxes, while Warmup Inbox's Basic plan is $15 per inbox a month, or $180 a year per inbox. At 20 inboxes, Warmup Inbox Basic costs roughly $3,600 a year against MailWarm's flat $190 a year.

Does Warmup Inbox have a free trial?

Yes, Warmup Inbox offers a 7-day free trial with no credit card required, per Warmup Inbox's pricing page. MailWarm instead offers an ongoing free tier limited to 1 inbox rather than a time-boxed trial.

What is the daily warmup volume difference between Warmup Inbox and MailWarm?

Warmup Inbox scales from 75 emails a day on Basic to 1,000 a day on Max. MailWarm caps out at 80 emails a day on its Pro plan, per MailWarm's own plan details. For most cold email sending volumes, MailWarm's cap is not the limiting factor.

Do Warmup Inbox or MailWarm work with Smartlead and Instantly?

Both are standalone warmup tools that run independently of your sending platform. They connect to inboxes directly and work alongside Smartlead, Instantly, or any other sequencer, though neither publishes a native in-app integration with either platform as of 2026.

Warmup and deliverability are one piece of a working outbound program. Domains, inbox count, sending limits, list quality, and copy all interact with whichever warmup tool you pick. We handle that infrastructure as part of every outbound engagement, including the campaigns behind our 3,000+ qualified B2B meetings booked. If you'd rather have someone else own the warmup, domains, and daily sending limits, see how Modern Inbound's setup service works.

By Rishabh Ambasta, Founder, Modern Inbound.