What is the best email warmup tool in 2026?
The one that matches how many inboxes you run. For a single address, a $19.50 specialist does the job. For ten, an unlimited-inbox platform costs about a sixth of lemwarm.
An email warmup tool sends a handful of emails every day from your new address to a network of other inboxes. Those inboxes open them, reply, and pull them out of spam. Gmail and Outlook see an address that sends a little, steadily, and gets replies, so your sender reputation climbs before your first campaign goes out.
The short answer: MailReach is the best standalone tool if you want proof of where your emails land, with 20 placement tests included. Instantly is the best pick if you already run cold email: unlimited inboxes and warmup from $37.60 a month billed annually. Warmy fits senders who email consumers, Smartlead fits agencies, lemwarm fits lemlist users (it's included), TrulyInbox is the free starting point, and Warmbox suits one or two inboxes.
Before you pick, answer one question: should warmup live on its own, or inside the tool that sends your campaigns? Depending on the answer, warming ten inboxes costs anywhere from $47 to $490 a month.
The ranking is editorial: a sponsored placement is always labeled on its card, and no affiliate link changes a score.
The best email warmup tool for your setup
$19.50 per inbox a month, 20 tests included
You already send cold emailGrowth at $47 a month, unlimited inboxes
Sending to Gmail, Yahoo, Outlook usersFrom $49 a month, 7-day trial, no card
Agency running dozens of inboxesBase at $39 a month, unlimited accounts
Zero budgetFree for 1 account, 10 emails a day
You're already on lemlistIncluded in every lemlist plan
7 email warmup tools compared
The full ranking. The price is the entry price listed by each vendor. Look first at whether you pay per inbox (MailReach, lemwarm, Warmbox) or a flat fee for unlimited inboxes (Instantly, Smartlead, TrulyInbox). Past three addresses, that one detail decides the bill.
| Best for | What sets it apart | Free plan | Team size | Visit | ||||
|---|---|---|---|---|---|---|---|---|
| 1 | MailReach | Best standalone tool | Placement tests included, warmup up to 100 emails a day | 4.3/5 | $19.50/inbox/mo | — | Freelancers, SMBs, agencies | Visit → |
| 2 | Instantly | Best bundled warmup | Unlimited inboxes and warmup inside the sending tool | 4.2/5 | Growth $47/mo, $37.60 billed annually | — | Teams running cold email | Visit → |
| 3 | Warmy | Best for B2C senders | Separate B2B and B2C plans, free diagnostic tools | 4.0/5 | From $49/mo | — | Senders to consumer inboxes | Visit → |
| 4 | Smartlead | Best for agencies | Unlimited accounts on every plan, no-card trial | 3.9/5 | Base $39/mo, $32 billed annually | — | Agencies, high volume | Visit → |
| 5 | lemwarm | Best for lemlist customers | Bundled with lemlist, 20,000+ domain network | 3.8/5 | Essential $29/address/mo, $24 annually | — | lemlist users | Visit → |
| 6 | TrulyInbox | The only free plan | Free forever for 1 account, unlimited accounts on paid plans | 3.7/5 | Free, then Starter $29/mo ($22 annually) | ✓ | Tight budgets | Visit → |
| 7 | Warmbox | For one to six inboxes | Plans sized by inbox count, easy to set up | 3.6/5 | Solo $15 to $19/mo depending on billing | — | Solo senders | Visit → |
Prices exclude tax and come from each vendor's official pricing page in 2026. Instantly's score is the one from our full review.
Is your tool missing from this page? Email us: hello@hackceleration.com
How we compared and scored
Most of the top results for this search are written by warmup vendors who rank themselves first. None of them work out the price for five or ten inboxes, which is where the gaps get huge, and few mention what Gmail actually asks of senders.
We read every vendor's pricing page and warmup documentation, Google's sender guidelines, then user feedback from forums and deliverability specialists. The core requirement: a tool that warms your inboxes itself through a network, with public pricing. Tools that do something else (send campaigns without dedicated warmup, measure reputation) are covered below without a score.
The five criteria carry equal weight. It's the grid behind all our reviews, which keeps a tool's score identical across the site. When scores are close, two things break the tie: real cost beyond one inbox, and how much the tool shows you about actual inbox placement.
- Ease of useTime to connect an inbox and start warming, clarity of the settings.20 %
- Value for moneyCost for 1, 5 and 10 inboxes, monthly and annual, and what's included.20 %
- Features and depthNetwork size, placement tests, alerts, DNS checks (SPF, DKIM, DMARC).20 %
- Customer support and assistanceDeliverability docs, responsiveness according to user feedback.20 %
- Available integrationsSupported providers (Google, Microsoft, SMTP), API, connected sending tools.20 %
No affiliate link changes a score or a rank.
MailReach
MailReach does one thing: deliverability. You connect a Google, Microsoft or any SMTP inbox, the tool ramps up warmup volume to as many as 100 emails a day. It asks for at least 14 days of warmup, with no campaigns, before you go live.
The real difference is the placement test: you send your actual email to seed inboxes and MailReach tells you where it lands at Gmail, Outlook and the rest. Every warmup subscription includes at least 20 test credits. That's the only way to see what a warmup score hides.
The catch: you pay per inbox. At $19.50 an address, ten inboxes run past $190 a month, when a sending platform with unlimited inboxes charges $47.
- Placement tests included in the subscription
- Warmup up to 100 emails per inbox per day
- Free SPF and DKIM checkers
- ✓Pure deliverability focus
- ✓Works with Google, Microsoft and any SMTP provider
- ✓Clear 14-day warmup phase before campaigns
- ✗Per-inbox pricing gets expensive at 10 addresses
- ✗No free trial listed
- ✗Doesn't send your campaigns
The best pick for one to five inboxes if you want proof, not a score. Past ten inboxes, keep it for testing and warm up elsewhere.
Instantly
Instantly is a cold email platform first. Warmup comes with no cap: connect as many inboxes as you like from any provider, and each one warms inside Instantly's pool, which users comparing it with Smartlead and lemlist describe as massive.
The math is simple. On Growth at $47 a month, your tenth inbox costs nothing more than your first. From three addresses up, it costs less than any per-inbox tool (MailReach, lemwarm, Warmbox), as long as you send your campaigns from Instantly. Smartlead Base ($39) and TrulyInbox Starter ($29) still have a lower entry price. Growth caps you at 1,000 uploaded contacts and 5,000 emails a month.
The catch: it isn't a diagnostic tool. A warmup score doesn't replace a placement test, and support is the weak spot users flag (3.6 out of 5 in our review).
- Unlimited inboxes and warmup on sending plans
- Warmup and campaigns in one place
- Cheaper than per-inbox tools from 3 inboxes
- ✓Flat price whatever the inbox count
- ✓One-click inbox connection
- ✓Very large warmup pool
- ✗Only worth it if you send from Instantly
- ✗5,000 emails a month cap on Growth
- ✗Slower support than the specialists
If you run cold email, this is the best value: warmup is effectively free. If you don't send from Instantly, go with a standalone tool.
Warmy
Warmy stands out on billing: you don't pay per inbox, you pay for the volume of warmup emails you need. A B2B plan targets Google Workspace and Microsoft 365 inboxes, a B2C plan targets consumer inboxes (Gmail, Yahoo, Outlook). Both start at $49 a month.
It claims a network of more than a million inboxes and offers a long list of free tools: deliverability test, domain reputation check, blacklist checker, SPF, DKIM and DMARC generators. Even without a subscription, they're handy for checking your setup before you start warming.
The catch: it has the highest entry price among standalone tools, and the pricing page doesn't say how many inboxes or daily emails that first tier covers. You have to run the calculator.
- B2C plan for Gmail, Yahoo and Outlook inboxes
- 7-day trial with no card
- Nearly thirty free diagnostic tools
- ✓Billing based on real warmup volume
- ✓Network of 1M+ inboxes claimed
- ✓Free DNS tools
- ✗$49 a month entry price
- ✗Unclear volume on the first tier
- ✗More complex than MailReach
The right call if your recipients are consumers or you want fine control over warmup volume. For two B2B prospecting inboxes, MailReach costs less.
Smartlead
Like Instantly, Smartlead is a cold email platform with built-in warmup. Its edge for agencies: every plan accepts unlimited email accounts at no extra cost, and the tool spreads sends across them (inbox rotation).
Base, at $39 a month or $32 billed annually, is the cheapest sending platform in this ranking. It covers 2,000 contacts and 6,000 sends a month. Agencies usually move up to Pro at $94 for 30,000 contacts.
The catch: as with Instantly, the warmup only matters if you send from Smartlead. And the first campaign takes more setup than on Instantly.
- Unlimited email accounts on every plan
- Inbox rotation to spread sends
- No-card free trial
- ✓Cheapest entry plan among sending tools
- ✓Built with agencies in mind
- ✓17% off with annual billing
- ✗Warmup only useful with its campaigns
- ✗More setup than Instantly
- ✗2,000 contact cap on Base
The agency pick for warming and sending at volume. For one or two inboxes, its warmup makes no sense without its campaigns.
lemwarm
lemwarm is lemlist's warmup, also sold on its own. Essential warms your inbox inside a network of 20,000+ domains; Smart warms with your real email templates and a network matched to your industry. It supports Google, Microsoft and SMTP inboxes.
Its method is the most cautious in the ranking. lemlist's help center recommends 30 to 40 warmup emails a day for a new inbox, adding one a day, which means about 40 days of ramp-up then 14 days of stabilization before the first campaign. Slow, but safe.
The catch is the standalone price: $29 per address, so $290 a month for ten inboxes. Outside lemlist, it's the most expensive option here.
- Included in every lemlist plan
- Warms your real templates on Smart
- 20,000+ domain network
- ✓Free if you already pay for lemlist
- ✓Careful, documented ramp-up
- ✓Industry-matched network on Smart
- ✗$29 per address on its own
- ✗No free trial listed
- ✗About 54 days before the first campaign
Keep it if you're on lemlist, you've already paid for it. On its own, it costs too much next to MailReach or an unlimited-inbox platform.
TrulyInbox
TrulyInbox is the only tool here with a free-forever plan: one inbox, 10 warmup emails a day. That's not much, but enough to keep an address active between campaigns.
Paid plans flip the logic: you connect unlimited accounts and pay for daily warmup volume. Starter covers 200 emails a day for $29 a month ($22 annually), Growth 1,000 a day for $99. The vendor recommends two warmup emails for every cold email you send, every day.
The catch: it's younger and less documented than MailReach, has no placement tests included, and most comparisons you'll find online are written by the vendor itself.
- Free-forever plan for one inbox
- Unlimited accounts on paid plans
- 14-day refund
- ✓The only free option in the ranking
- ✓No per-inbox pricing
- ✓7-day trial, no card
- ✗10 emails a day on free
- ✗No placement tests included
- ✗Little independent user feedback
A good starting point if your budget is zero. Once you prospect seriously, a paid plan or a sending platform does better.
Warmbox
Warmbox sells plans by inbox count: one inbox and 50 emails a day on Solo, three inboxes and 250 a day on Start-up, six inboxes and 500 a day on Growth. The lower price is the annual one.
For a single address, Solo is among the cheapest on the market at $15 to $19 a month. The next tier jumps, though: Start-up works out to about $26 per inbox monthly, more than MailReach.
The catch: no trial listed, little emphasis on placement testing, and a steep price jump from the second inbox.
- Clear plans by inbox count
- Solo among the cheapest for one inbox
- Team seats included
- ✓Easy to get going
- ✓Readable pricing
- ✓Support on every plan
- ✗Price jump from 2 inboxes
- ✗No free trial listed
- ✗Fewer diagnostics than MailReach
Fine for one inbox on a small budget. Beyond that, MailReach or an unlimited-inbox platform is the smarter buy.
Two more tools worth knowing
Both come up in every warmup discussion, but they don't do quite the same job as the ranked tools, so we cover them without a score.
lemlist: warmup included with the sending platform
Outreachlemlist is a cold email platform that includes lemwarm in every plan. The Email plan costs $69 a month for the whole team, or $55 billed annually. If you need both a sending tool and warmup, it's a direct alternative to Instantly: pricier, but stronger on personalization.
Our review breaks down its plans: read the lemlist review.
- Price
- Email $69/mo, $55 annually
- Best for
- Teams that personalize heavily
- Limit
- Costs more than Instantly
Google Postmaster Tools: the official scoreboard, free
MonitoringPostmaster Tools is Google's free dashboard showing your domain reputation and spam complaint rate at Gmail. It doesn't warm anything, but it's the number Google enforces: stay under a 0.3% reported spam rate, and aim for under 0.1%.
Hook it up on day one of warmup. A green score in your warmup tool means nothing if Postmaster Tools shows low reputation.
- Price
- Free
- Best for
- Anyone sending to Gmail
- Limit
- Measures only, no warmup
What warming your inboxes really costs
The headline price is for one inbox, often billed annually. But few teams prospect from a single address: most spread sends across three to ten inboxes to stay under the limits. Here's the monthly, no-commitment price for 1, 5 and 10 inboxes.
One inbox
Five inboxes
Ten inboxes or more
- Check whether the price is per inbox or for unlimited inboxes.
- Check whether the listed price assumes a year paid up front.
- If you already send from lemlist, Instantly or Smartlead, don't pay for a second warmup.
- Compare daily warmup volume included, not just inbox count.
- Keep at least one placement-testing tool, even when warmup is bundled.
- Add the cost of the inboxes themselves: each Google Workspace or Microsoft 365 seat is billed too.
What Gmail actually checks
Google's sender guidelines never mention warmup tools. They talk about authentication, complaints and sending pace. A warmup tool helps with pace, not with the rest.
What Google requires
What Google recommends
What deliverability pros say
- Set up SPF, DKIM and DMARC before you start warming.
- Send from a secondary domain, never your main website domain.
- Verify your list before every campaign: a high bounce rate wipes out weeks of warmup.
- Keep your reported spam rate under 0.1% in Postmaster Tools.
- Run a placement test before every new campaign.
- Pause sending at the first sign of a reputation drop.
Six settings that keep you out of spam
What teams sending cold email every day take away from vendor documentation and user feedback. They apply whatever tool you use.
Warm for two weeks minimum
Ramp-upMailReach asks for at least 14 days before the first campaign; lemlist plans about 54 for a new inbox. Between the two, count two weeks for an inbox on an older domain, four to eight on a brand-new one.
- Benchmark
- 14 days minimum, 4 to 8 weeks for a new domain
Add one email a day
Ramp-uplemlist's help center recommends a target of 30 to 40 warmup emails a day for a new inbox, reached by adding one email a day. A faster ramp creates exactly the spike Google tells you to avoid.
- Setting
- Target 30 to 40 a day, +1 per day
Don't switch warmup off after launch
MaintenanceOngoing warmup keeps your reputation up while campaigns run. lemlist suggests dropping to about ten warmup emails a day once you launch, rather than stopping. TrulyInbox keeps a ratio of two warmup emails per cold email.
- Setting
- About 10 warmup emails a day for maintenance
Spread sends across several inboxes
VolumeFive inboxes sending 30 a day beat one inbox sending 150. That's why unlimited-inbox platforms (Instantly, Smartlead) became the agency default: cost no longer tracks address count.
- Benchmark
- A few dozen cold emails per inbox per day
Prospect from a secondary domain
SafetyBuy a lookalike domain (a hyphen or a different extension) for cold email. If its reputation drops, your invoices and customer emails, sent from your main domain, stay untouched.
- Setting
- One domain dedicated to outreach
Run a placement test, not just a score
MonitoringBefore each new campaign, send your real message to seed inboxes. MailReach includes at least 20 tests with warmup; Warmy offers a free test. It's the only way to know whether your copy, not just your inbox, gets past the filters.
- Setting
- One test before every campaign
Your inboxes are warm, now what
These pages go further on cold email, depending on what you need.
Our ranking of cold email platforms.
You're on lemwarm and want outSwitch from lemwarmAlternatives and a switch that keeps your reputation.
You're torn between the two big namesInstantly vs lemlistHead to head, criterion by criterion.
Smartlead isn't cutting itSwitch from SmartleadWhere to go next.
You want the full picture on InstantlyOur Instantly reviewPricing, limits, who it fits.
You want us to build your outreach with youOur growth hacking agencyTargeting, sequences, deliverability.
Email warmup · FAQ
Does email warmup still work in 2026?
Yes, for a new or dormant inbox, but it's no longer enough on its own. Google mostly judges your authentication (SPF, DKIM, DMARC), complaint rate and sending consistency. Warmup handles pace; a poorly targeted list will tank your reputation whatever your score says.How long should you warm up a new email address?
At least two weeks before your first campaign, which is MailReach's minimum. For a new inbox, lemlist recommends about 40 days of ramp-up then 14 days of stabilization. On a brand-new domain, plan for four to eight weeks.Is there a free email warmup tool?
Yes: TrulyInbox warms one inbox for free at 10 emails a day. Instantly and Smartlead have no free plan, but their trials include warmup. Warmy offers a 7-day trial with no card and nearly thirty free diagnostic tools.How many warmup emails should you send per day?
30 to 40 a day for a new inbox, per lemlist's help center, reached by adding one email a day. MailReach goes up to 100 a day. Once campaigns are live, keep about ten warmup emails a day instead of stopping.Do I need a separate warmup tool if I use Instantly or lemlist?
No. Instantly, Smartlead and lemlist include warmup in their plans with no per-inbox fee. A second tool just doubles the bill. Add a placement-testing tool instead to check where your real emails land.Can a warmup tool hurt my sender reputation?
Yes, if its network is low quality or you ramp too fast. Some deliverability specialists advise against warmup networks altogether and prefer a slow ramp to real, engaged recipients. Watch Postmaster Tools: it's Google's number, not the vendor's.Can I stop warmup once my reputation is built?
You can, but it's risky. lemlist recommends leaving it on at low volume, or running one or two placement tests a month if you stop. Your reputation belongs to your domain and inboxes, not the tool, so you keep it when you switch tools.Is lemwarm free with lemlist?
Yes: every lemlist plan includes lemwarm, starting with the Email plan at $69 a month for the team. Sold on its own, lemwarm costs $29 per address a month, or $290 for ten inboxes.