Email warmup tools in 2026: what they cost, whether they work, and what matters more

The short answer

If you send cold email from Instantly, Smartlead, lemlist or Saleshandy, you already have warmup: it is part of their plans, so a separate email warmup tool is rarely worth paying for. Standalone tools cost $15 to $49 per inbox a month; MailReach ($25, or $20 billed annually) adds spam tests, and Warmup Inbox starts at $19 with a free placement test.

Treat warmup as a small, contested part of deliverability. Google pushed at least one warmup service off its API, deliverability experts warn against simulated engagement, and in September 2026 Validity launched a blocklist aimed at synthetic domain warming. Authentication, low volume per inbox, verified lists and a spam rate under 0.3 percent decide where your email lands.

What email warmup is, and what it is not

An email warmup tool connects your inbox to a pool of other inboxes. It sends a few emails a day between them, and the pool opens them, replies, and moves any that land in spam back to the inbox. The volume steps up over weeks. The idea is that mailbox providers see a new address with steady, wanted traffic before it starts sending cold email.

What it is not: a measure of where your campaigns land. A warmup score is calculated inside the tool's own pool; Instantly, for example, defines its health score as the share of warmup emails that reached the inbox over seven days. Your real prospects use different mail systems and have never heard of you. To see where a real email lands, you run a placement test: one email sent to a set of test inboxes, read as a rough guide.

Email warmup tools compared: prices and features

Standalone warmup tools charge by the inbox, or by daily volume. Every network size below is the vendor's own claim, and several vendors publish more than one; none has been audited.

Email warmup tools in 2026: price per inbox, network claim and extras

	Price a month	Billed annually	Network, by its own count	Extras
MailReach	$25 an inbox (1 to 5); $16 at 51 to 100	$20 an inbox	30,000+ inboxes, mostly Google Workspace and Microsoft 365	Spam test credits
lemwarm	$29 (Essential), $49 (Smart), per inbox	$24, $40	20,000+ domains	Included in lemlist plans
Warmup Inbox	$19 (Basic, 75 a day), $59, $99	$15, $49, $79	30,000+ inboxes	Free placement test, blacklist monitoring
Warmbox	$19 for 1 inbox, $79 for 3, $159 for 6	$15, $69, $139	10,000 to 35,000+ (its pages differ)	Free check of 100+ blacklists
TrulyInbox	$29 for 200 a day, unlimited inboxes	$22	40,000+ inboxes	Supplies Saleshandy's warmup; its prices conflict
Warmy	Demo only since about May 2026	Not published	1M+ network	DMARC tracker, SPF and DMARC generators
Warmforge	Free with Salesforge	Free with Salesforge	Not stated	Sold alone at about $9 to $12 a slot

MailReach

Spam tests included

Best for: senders who want a standalone warmup with spam tests, priced per inbox and cheaper at volume.

Strengths

• $25 an inbox a month, $20 billed annually
• Falls to $16 an inbox at 51 to 100 inboxes
• Spam test credits included
• Says its pool is mostly Google Workspace and Microsoft 365

Watch-outs

• A separate bill if your sequencer already warms up
• Network size is its own claim, not audited

Skip it if: you send from a sequencer with warmup included; switch that on instead.

Pricing: $25 an inbox a month for 1 to 5 inboxes ($20 billed annually), down to $16 at 51 to 100.

lemwarm

lemlist's warmup

Best for: lemlist users, who get it in their plan, and teams that want lemlist's warmup on another sending tool.

Strengths

• Included in lemlist plans (switch it on)
• Sold alone from $29 an inbox, $24 billed annually
• Says it warms with real user inboxes, 20,000+ domains

Watch-outs

• Not active in lemlist's free trial
• The Smart plan costs $49 an inbox, $20 more
• Its network size differs across lemlist's pages

Skip it if: you use another sequencer with its own warmup.

Pricing: Essential $29 an inbox a month ($24 billed annually); Smart $49 ($40).

Warmup Inbox

Low entry

Best for: a founder warming one or two inboxes outside a sequencer, who wants a placement test and blacklist alerts.

Strengths

• Basic at $19 a month, $15 billed annually
• Free placement test
• Blacklist monitoring

Watch-outs

• Basic caps warmup at 75 emails a day
• Network size is its own claim, not audited

Skip it if: your sequencer already includes warmup.

Pricing: Basic $19 a month ($15 billed annually), Pro $59 ($49), Max $99 ($79).

Warmbox

Blacklist checks

Best for: small teams warming one to six inboxes who want a free blacklist checker alongside.

Strengths

• Solo at $19 for one inbox, $15 billed annually
• Free check against 100+ blacklists
• Runs Apollo's warmup for Apollo's plans that include it

Watch-outs

• Its pages give network sizes from 10,000 to 35,000+
• Plans jump from 1 to 3 to 6 inboxes

Skip it if: you need more than six inboxes; per-inbox pricing elsewhere scales better.

Pricing: Solo $19 (1 inbox), Start-up $79 (3), Growth $159 (6); $15, $69 and $139 billed annually.

Built-in warmup: what your sequencer already includes

Most cold email tools now include warmup in their plans, which is why a standalone tool is rarely needed. Instantly warms unlimited accounts on every plan, from Growth at $47 a month ($37.60 billed annually), and sells a premium private pool from $500 a month. Smartlead includes warmup and unlimited mailboxes from Base at $39. lemlist includes lemwarm from its Email plan at $69 ($55 billed annually), switched on by hand. Saleshandy includes warmup, supplied by TrulyInbox, from its Starter plan at $41 ($34 billed annually).

Warmup built into cold email tools: the cheapest plan that includes it

	Cheapest plan with warmup	Inboxes warmed	Whose pool
Instantly	Growth: $47 a month, $37.60 billed annually	Unlimited	Its own: 1M+ or 4.2M+, by its pages
Smartlead	Base: $39 a month	Unlimited	Its own
lemlist	Email: $69 a month, $55 billed annually	Included; switch it on	lemwarm's
Saleshandy	Starter: $41 a month, $34 billed annually	Unlimited	TrulyInbox's
Apollo	Select plans	1 mailbox a seat; more at 200 credits per 30 days	Warmbox's

Our Instantly vs Smartlead comparison (opens in a new tab) covers the two sequencers in full, including their paid placement tests, and our cold email software roundup (opens in a new tab) prices ten more.

Does email warmup work?

Nobody has published an independent, controlled test. The evidence for warmup comes from the companies that sell it; one, InboxKit, reports 88 percent inbox placement with warmup against 54 percent without, on its own data.

The evidence against is growing. Google told GMass in 2022 to stop its warmup or lose access to the Gmail API, and GMass closed it in January 2023; Saleshandy and Growbots stopped warming Gmail accounts the same year. Gmail's program policies bar automating Gmail in a way that misleads users. In September 2026, Validity launched Heatwave, a blocklist aimed at synthetic domain warming, which it says has listed more than a million domains and which Comcast, Proofpoint, Spamhaus and SURBL use or are evaluating.

Deliverability practitioners agree on the principle. Al Iverson of Spam Resource advises avoiding warmup services that simulate engagement (October 2026); Word to the Wise argues that warmup works only for mail people want; and the email provider Resend calls warmup services harmful to deliverability. A warmup score cannot settle the question, because it measures the tool's own pool, not your prospects' inboxes.

How long to warm up, and how much to send after

Sources disagree, and some disagree with themselves. Google's own advice is to raise volume gradually and, after deferrals, to grow by 25 to 100 percent a day. Word to the Wise suggested four to six weeks at Gmail; Al Iverson describes IP warming that can take five to eight weeks. The vendors: Instantly says at least two weeks and a health score above 90 percent; Smartlead's pages say anything from two weeks to 30 days or more; lemlist's say three to five weeks.

After warmup, the vendors' daily limits per inbox cluster between 25 and 50 campaign emails, which is why cold senders spread volume across several inboxes and domains rather than pushing one. Google Workspace itself caps a user at 2,000 messages a day, or 500 on a trial account, far above what cold email should approach.

What matters more than warmup

Gmail and Yahoo have required bulk senders, those sending more than 5,000 messages a day to their users, to meet a set of rules since February 2024: SPF, DKIM and DMARC with alignment, one-click unsubscribe honored within two days, and a spam rate under 0.3 percent, ideally under 0.1. Microsoft's Outlook.com added its own authentication rules in May 2025, and since November 2025 Gmail has started rejecting mail that fails them. Cold senders rarely reach 5,000 a day per domain, but the rules show what mailbox providers check.

Sender rules at Gmail, Yahoo and Outlook

	Gmail and Yahoo	Outlook.com
Who must comply	Senders of 5,000+ messages a day	Senders of 5,000+ messages a day to Outlook.com addresses
SPF, DKIM and DMARC	Required, aligned; DMARC p=none is enough	Required, aligned; DMARC p=none or stricter
One-click unsubscribe	Required, honored within 2 days	Recommended, not required
Spam rate	Under 0.3%, ideally under 0.1%	Not stated as a threshold
Since	February 2024; rejections since November 2025	May 5, 2025
If you fail	Temporary and permanent rejections	Rejected with error 550 5.7.515

• Send from separate domains. Keep cold email off your main domain, so a reputation problem does not reach your company's own mail.
• Verify every list before every campaign. Bounces hurt faster than warmup helps. Our email verification guide (opens in a new tab) compares the tools.
• Keep volume low per inbox. A few inboxes at modest volume beat one inbox pushed hard.
• Write to people who can use what you sell. Replies and the absence of spam complaints are the signals warmup tries to imitate.
• Watch Google Postmaster Tools if you can. It needs at least hundreds of messages a day to personal Gmail addresses before it shows data, so small senders often see nothing.

Which email warmup tool to choose

Questions

What is an email warmup tool?

A service that connects your inbox to a pool of other inboxes, which exchange emails with it, open and reply to them, and move them out of spam. Volume steps up over weeks before you send real campaigns.

Does email warmup work?

There is no independent test. Vendors report better placement; Google pushed a warmup service off its API in 2022, experts warn against simulated engagement, and a 2026 blocklist targets synthetic warming. Authentication and list quality matter more.

How long should I warm up a new email inbox?

Sources range from two weeks (Instantly) to four to six weeks (Word to the Wise). Whatever you choose, ramp real sending slowly: Google advises raising volume gradually.

How much does an email warmup tool cost?

Standalone tools cost $15 to $49 per inbox a month: Warmbox and Warmup Inbox from $19, MailReach $25, lemwarm $29. Instantly, Smartlead, lemlist and Saleshandy include warmup in their plans.

Do I need a warmup tool if I use Instantly or Smartlead?

No. Both include warmup on every plan, with unlimited inboxes. Switch it on for new inboxes; a second warmup tool on the same inbox adds cost, not reach.

What is the best email warmup tool?

For most founders, the one already in their sequencer. Standalone, MailReach adds spam tests at $25 an inbox and gets cheaper at volume; Warmup Inbox starts at $19 with a free placement test.

Is email warmup against Google's rules?

Gmail's program policies bar automating Gmail in a misleading way, and Google told GMass in 2022 to stop its warmup or lose Gmail API access. Google has not published a statement naming warmup tools.

How many cold emails can I send per inbox per day?

Vendors' figures cluster between 25 and 50 campaign emails per inbox per day after warmup: Instantly says 30, lemlist 25 to 40. Smartlead's pages range up to 100. Spread volume across inboxes rather than pushing one.

Sources

1. lemwarm (opens in a new tab), lemlist, checked October 21, 2026
2. lemwarm review (opens in a new tab), lemlist, checked October 21, 2026
3. MailReach pricing (opens in a new tab), Emelia, checked October 21, 2026
4. Gmail warmup (opens in a new tab), MailReach, checked October 21, 2026
5. Pricing (opens in a new tab), Warmbox, checked October 21, 2026
6. The Warmbox inbox network (opens in a new tab), Warmbox, checked October 21, 2026
7. Pricing (opens in a new tab), Warmup Inbox, checked October 21, 2026
8. Warmy pricing (opens in a new tab), MailReach (a competitor), checked October 21, 2026
9. How to choose an email warm-up service (opens in a new tab), Warmy, checked October 21, 2026
10. TrulyInbox (opens in a new tab), Capterra, checked October 21, 2026
11. Network (opens in a new tab), TrulyInbox, checked October 21, 2026
12. Email warm-up tools (opens in a new tab), Salesforge, checked October 21, 2026
13. Deliverability experts acquire Mailwarm to launch mailX (opens in a new tab), MarTech Series, checked October 21, 2026
14. Warmup is shutting down (opens in a new tab), GMass, checked October 21, 2026
15. We are shutting down our email warm-up for Google accounts (opens in a new tab), Saleshandy, checked October 21, 2026
16. We're disabling warm-up for Gmail (opens in a new tab), Growbots, checked October 21, 2026
17. Instantly pricing guide (opens in a new tab), Cleanlist (a competing vendor), checked October 21, 2026
18. Premium private warmup pool (opens in a new tab), Instantly, checked October 21, 2026
19. Warmup health score (opens in a new tab), Instantly, checked October 21, 2026
20. Account and campaign limits (opens in a new tab), Instantly, checked October 21, 2026
21. FAQ (opens in a new tab), Smartlead, checked October 21, 2026
22. Email deliverability guide (opens in a new tab), Smartlead, checked October 21, 2026
23. Pricing (opens in a new tab), lemlist, checked October 21, 2026
24. How to warm up an email account (opens in a new tab), lemlist, checked October 21, 2026
25. Understand sending limits in lemlist (opens in a new tab), lemlist, checked October 21, 2026
26. Pricing (opens in a new tab), Saleshandy, checked October 21, 2026
27. Saleshandy platform plan pricing 2026 (opens in a new tab), Saleshandy, checked October 21, 2026
28. Does Saleshandy offer email warm-up? (opens in a new tab), Saleshandy, checked October 21, 2026
29. Use email warmup to improve deliverability (opens in a new tab), Apollo, checked October 21, 2026
30. Validity launches Heatwave blocklist (opens in a new tab), Validity, checked October 21, 2026
31. ISP deliverability guide: Comcast Xfinity (opens in a new tab), Al Iverson, Spam Resource, checked October 21, 2026
32. Spam folder placement during IP warming (opens in a new tab), Al Iverson, Spam Resource, checked October 21, 2026
33. Warmup is communication (opens in a new tab), Word to the Wise, checked October 21, 2026
34. Warmup advice for Gmail (opens in a new tab), Word to the Wise, checked October 21, 2026
35. Avoid warmup services (opens in a new tab), Resend, checked October 21, 2026
36. Email warmup guide (opens in a new tab), InboxKit (a vendor), checked October 21, 2026
37. Gmail program policies (opens in a new tab), Google, checked October 21, 2026
38. Ramp up sending volume (opens in a new tab), Google, checked October 21, 2026
39. Gmail sending limits in Google Workspace (opens in a new tab), Google, checked October 21, 2026
40. New Gmail protections for a safer, less spammy inbox (opens in a new tab), Google, checked October 21, 2026
41. Email sender guidelines (opens in a new tab), Google, checked October 21, 2026
42. Email sender guidelines FAQ (opens in a new tab), Google, checked October 21, 2026
43. Postmaster Tools (opens in a new tab), Google, checked October 21, 2026
44. Sender best practices (opens in a new tab), Yahoo, checked October 21, 2026
45. Outlook's new requirements for high-volume senders (opens in a new tab), Microsoft, checked October 21, 2026
46. Seed lists and their limitations (opens in a new tab), Suped (a vendor), checked October 21, 2026

How these comparisons are made: from each vendor's own documentation and pricing pages, independent reviews and the policies of the platforms involved, each linked and dated. Prices change often; check the vendor's page before you buy.