How we make this list: we compare pricing pages, product documentation and public user reviews. Ratings come from G2, Capterra or Trustpilot, with the date we checked them.
Key takeaways
- Email warmup builds sender reputation by gradually sending to real inboxes that open and reply, and it matters most for new domains and new mailboxes before cold outreach.
- Per-inbox pricing is a trap at scale: Lemwarm at 10 inboxes costs about $290 per month, while Instantly covers the same job for about $30, since its plans are unlimited.
- Placement testing matters more than a green checkmark, so favor tools with inbox placement tests over tools that only show warmup activity.
- No warmup tool protects reputation after you hit send: one bad batch with spam traps or outdated addresses can undo weeks of warmup overnight.
Quick comparison
| Tool | Best for | Starting price | Free plan |
|---|
 Instantly | Warmup bundled with cold email | $30 per month | No |
 MailReach | Standalone warmup with placement tests | $19.50 per mailbox per month | No |
 Lemwarm | Teams already running lemlist | $24 per email per month | No |
 Smartlead | High-volume senders, many mailboxes | $32 per month | No |
 Warmup Inbox | Blacklist monitoring and delisting | $15 per inbox per month | No |
 TrulyInbox | Free tier and unlimited mailboxes | Free | Yes |
 Warmbox | Control over the ramp curve | $15 per month | No |
 Folderly | Enterprise deliverability programs | $96 per mailbox per month | No |
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#1Instantly
Best for: Warmup bundled with cold email4.8/5 on
G2 (4,161 reviews, checked Oct 2026)
Visit instantly.ai
Starting price$30 per month
Free planNo
Instantly bundles unlimited warmup with a full cold email platform, making it the best value for teams running outreach across many mailboxes. Guides list Growth from $30 per month on annual billing, or $47 monthly, with Hyper Growth at $97 and Light Speed at $358, and warmup runs across a network of more than 1,000,000 accounts. Tests show 92 to 95 percent primary inbox placement in published comparisons, though results vary by test methodology.
Warmup is bundled rather than standalone, so teams that only need warmup pay for outreach features too, and monthly pricing runs higher than annual. For cold outreach teams with multiple inboxes, Instantly offers the best per-inbox economics here, since the price stays flat as mailboxes grow.
What we like- Unlimited warmup on all plans
- 1,000,000 plus warmup accounts
- Bundled with outreach platform
Watch out for- Warmup is bundled, not standalone
- Monthly price of $47 versus $30 annual
- Placement test results vary by test
Starting price$19.50 per mailbox per month
Free planNo
MailReach offers standalone warmup with anti-fingerprinting and built-in placement testing, making it the best choice for B2B teams that want dedicated warmup plus outcome validation. Guides list pricing from $19.50 per mailbox per month on annual billing, or $25 monthly, with a network of more than 30,000 professional inboxes and placement test credits included. Tests show 92 to 93 percent primary placement in published comparisons.
Per-mailbox pricing scales fast: 10 mailboxes cost about $200 per month on annual billing, versus $30 for Instantly, so the break-even point sits around three inboxes. For teams that need placement testing and dedicated warmup validation, MailReach offers the strongest standalone testing here.
What we like- Standalone warmup with anti-fingerprinting
- Built-in placement testing
- 30,000 plus professional inboxes
Watch out for- Per-mailbox pricing scales fast
- $25 per mailbox monthly versus $19.50 annual
- No free plan
Starting price$24 per email per month
Free planNo
Lemwarm suits teams already running lemlist, with deep integration into the outreach platform and a network of more than 20,000 real inboxes. Tests show 96 percent primary inbox placement in published comparisons, among the highest in this list, and guides list pricing from $24 per email per month on annual billing, or $29 monthly, with warmup free alongside a lemlist plan. Its simple setup and deliverability test tool suit teams that want warmup inside their existing workflow.
Per-email pricing scales fast: 10 inboxes cost about $290 per month, versus $30 for Instantly, so lemlist users should weigh whether the integration justifies the per-inbox cost. For lemlist teams that value native warmup and strong placement results, Lemwarm is the natural pick.
What we like- Deep lemlist integration
- 20,000 plus real inboxes
- 96 percent primary placement in tests
Watch out for- Per-email pricing scales fast
- $29 monthly versus $24 annual
- Free only with a lemlist plan
#4Smartlead
Best for: High-volume senders, many mailboxes4.5/5 on
G2 (448 reviews, checked Oct 2026)
Visit smartlead.ai
Starting price$32 per month
Free planNo
Smartlead suits high-volume senders and agencies running many mailboxes, with unlimited mailboxes on all plans and bundled warmup inside a full outreach platform. Guides list Basic from $32 per month on annual billing, or $39 monthly, with white-label client portals for agencies and a curated private warmup network. Tests show 91 to 97 percent primary placement depending on methodology, a wide range that reflects different test setups.
Monthly pricing runs higher than annual, and the curated network size is not disclosed, so placement results should be tested on your own domains. For agencies scaling outbound across many mailboxes, Smartlead offers the best agency workflow here.
What we like- Unlimited mailboxes
- Bundled warmup for agencies
- White-label client portals
Watch out for- $39 monthly versus $32 annual
- Placement results vary by test, 91 to 97 percent
- Curated network size not disclosed
Starting price$15 per inbox per month
Free planNo
Warmup Inbox suits beginners and small teams that want blacklist monitoring and automated delisting alongside warmup, with a network of more than 30,000 real inboxes. Guides list pricing from $15 per inbox per month on annual billing, or $19 monthly, with a 7-day trial and dead-simple setup. Tests show 93 percent primary placement in published comparisons, with ESP-specific warming strength for Gmail.
Per-inbox pricing scales fast: 10 inboxes cost about $190 per month, and there is no placement testing, only health checks. For small teams that want simple warmup with blacklist monitoring, Warmup Inbox offers the easiest start here.
What we like- Blacklist monitoring and automated delisting
- 30,000 plus real inboxes
- Simple setup for beginners
Watch out for- Per-inbox pricing scales fast
- $19 monthly versus $15 annual
- No placement testing, health checks only
Starting priceFree
Free planYes
TrulyInbox suits deliverability at scale without paying per inbox, with a free tier and unlimited mailboxes on every paid plan, plus a network of more than 40,000 real inboxes. Tests show 98 percent primary placement in one published comparison, the highest figure in this list, though other tests did not cover it, so treat that figure as directional. Paid plans start from $22 per month on annual billing, with granular per-inbox reporting for analytics-heavy users.
The free tier limits features, and paid pricing varies by source, with some guides listing $29 per month. For teams that want free warmup to start and unlimited mailboxes as they scale, TrulyInbox offers the best free entry here.
What we like- Free tier available
- Unlimited mailboxes on paid plans
- 98 percent primary placement in one test
Watch out for- Paid plans from $22 per month annual
- Granular reporting suits analytics-heavy users
- Free tier limits features
Starting price$15 per month
Free planNo
Warmbox suits solo operators who want control over the ramp curve, with 35,000 inboxes and set-and-forget simplicity at a low entry price. Guides list Solo from $15 per month on annual billing, or $19 monthly, with tiers rising to $99 at 10 inboxes, which shows its per-inbox tier structure. Tests show 90 percent primary placement, trailing the leaders in this list but adequate for budget warmup.
Per-inbox tiers scale faster than unlimited plans, and placement results trail Lemwarm and TrulyInbox. For solo operators who want ramp control at a low entry price, Warmbox offers the most customizable budget option here.
What we like- Control over the ramp curve
- 35,000 inboxes
- Set-and-forget simplicity for solo operators
Watch out for- Per-inbox tiers scale to $99 at 10 inboxes
- 90 percent primary placement in tests trails leaders
- No free plan
Starting price$96 per mailbox per month
Free planNo
Folderly suits enterprise deliverability programs, with a full suite covering placement checks, spam trigger analysis, and inbox insights alongside warmup. Tests show 95 to 96 percent primary placement, among the strongest in this list, and guides list pricing from $96 per mailbox per month on annual billing, or up to $120 in some comparisons. Its depth suits teams whose deliverability problems need diagnosis, not just warmup.
The $96 per mailbox price is the highest here and poor value for small teams, since 10 mailboxes would cost nearly $1,000 per month. For enterprises with damaged deliverability that need diagnosis and repair, Folderly offers the deepest deliverability suite here.
What we like- Enterprise deliverability suite
- Placement checks and spam trigger analysis
- 95 to 96 percent placement in tests
Watch out for- $96 per mailbox per month is the highest price here
- Enterprise focus means poor value for small teams
How we chose
We compared 2026 warmup tool tests and pricing guides, checking starting prices, per-mailbox versus unlimited models, network sizes, placement test results, and trial availability. We favored tools with published pricing and placement test evidence, and we flagged where test results vary by methodology, since no test is perfectly neutral. We did not claim hands-on testing, and prices change often, so confirm current numbers on each vendor site before buying.
Warmup math that matters
Cost at 1, 5, 10, and 25 inboxes separates unlimited tools from per-inbox tools fast. Instantly costs $30 at every count, Smartlead costs $39, and TrulyInbox costs $29, while Warmup Inbox rises from $19 to $475, Lemwarm from $29 to $725, and MailReach from $20 to $500. The break-even point sits around three inboxes: below that, per-inbox tools can be cheaper, while above it, unlimited models win every time. Choose by your mailbox count at scale, not by the single-inbox headline.
Warmup timeline and maintenance
Warmup takes two to four weeks for new domains and mailboxes, with gradual ramp curves that increase daily sending volume slowly rather than jumping to full volume. Active maintenance matters more than any single tool choice: every price and ownership fact in guides was checked in July 2026, and tools that stop maintaining their networks lose effectiveness as providers change filters. If warmup stalls on rejections, start by reading bounce codes before changing anything else, since a 5.7.1 bounce signals a different problem than a volume throttle.
Protecting reputation after warmup
No warmup tool protects reputation after you hit send, since one bad batch with spam traps, honeypots, or outdated addresses can undo weeks of warmup overnight. Verify email lists before sending, keep bounce rates under 4 percent, disable open tracking pixels that add a tracking domain, and follow Google sender guidelines on authentication and complaint rates. Warmup builds reputation, but list quality and sending practices keep it.
Frequently asked questions
How long does email warmup take?
Warmup takes two to four weeks for new domains and mailboxes, with gradual daily volume increases rather than an immediate jump to full sending. Older domains with existing reputation need less warmup, while brand-new domains need the full ramp period.
Is email warmup necessary for cold outreach?
Yes, for new domains and mailboxes, since sending high volumes from a cold domain triggers spam filters and damages reputation before campaigns start. Established domains with good reputation need less warmup, but new sending domains should always warm up first.
What is the cheapest email warmup tool?
TrulyInbox offers a free tier, while Warmbox starts at $15 per month and Warmup Inbox at $15 per inbox per month on annual billing. For multiple mailboxes, Instantly at $30 per month unlimited offers the best total cost, since per-inbox tools scale fast.
Does warmup guarantee inbox placement?
No, warmup builds sender reputation but cannot guarantee placement, since list quality, content, authentication, and complaint rates all affect deliverability. Placement testing matters more than a green warmup checkmark, so test real campaigns before scaling volume.
Can I warm up a domain and then send to purchased lists?
No, purchased lists harm deliverability regardless of warmup, since they contain spam traps, outdated addresses, and recipients who never consented. Warmup cannot fix bad data, and one bad batch can undo weeks of reputation building overnight.
Sources we checked (10)
- https://instantly.ai
- https://mailreach.co
- https://www.lemlist.com
- https://www.smartlead.ai
- https://www.warmupinbox.com
- https://trulyinbox.com
- https://warmbox.ai
- https://folderly.com
- https://outreachbloom.com/email-warmup
- https://www.saleshandy.com/blog/email-warm-up-tools/
Is your product missing or out of date?
We review this list regularly. Vendors can request a listing, send updated pricing or ask about featured placement.
Shihab Mia · Founder, Rankite
Shihab has 5+ years in B2B and SaaS SEO. He writes Rankite's software buying guides from pricing pages, documentation and public user reviews. More about Shihab.