Best Cold Email Warmup Tools in 2026

Cold email warmup tools send automated, friendly mail between inboxes so a new sending domain builds a track record before your real campaigns go out. Almost all of them do that same job the same way, through a network of accounts that open, reply to, and rescue each other's mail from spam.

Because the mechanic is near identical everywhere, the useful comparison is not "which network is best." It is how each tool charges, whether it shows you real inbox placement or just its own score, and whether you are already paying for warmup without knowing it. Every price below was checked on the vendor's own pricing page in July 2026.

Some links below are affiliate links, which means we may earn a commission at no extra cost to you. It does not change what we recommend. One tool on this page carries an affiliate link. The rest are named without one, so you can compare on the same terms.

Cold email warmup tools compared

Two things in that table decide most of the money. The first is whether a tool charges per inbox or a flat rate, because at 20 mailboxes those two models are hundreds of dollars a month apart. The second is whether you already have warmup bundled, in which case the honest answer is to buy nothing.

What changed about warmup, and why it matters before you buy

For years the play was to crank warmup high and let it run. That window has closed. Mailbox providers got much better at recognising warmup networks, where the same pool of accounts email each other in patterns no real person produces. Lean on that too hard and you build reputation that is fake, and fake reputation falls apart the second real sending starts.

There is a second problem worth knowing before you pay for a warmup score. Every tool here grades engagement inside its own network, which is the one place it controls. That is why operators keep reporting scores above 90 while live campaigns land in spam, a pattern that showed up repeatedly when we read through 800 cold email tool reviews. Treat a warmup score as a weak signal and campaign outcomes as the truth.

The current approach is lighter. Keep warmup modest and always on in the background, ramp your real sending slowly, and let genuine replies from prospects carry most of the weight. Warmup is a primer now, not the paint.

How to judge a warmup tool

Four things actually differ between the options below.

• How it charges. Per inbox or flat rate by volume. This is the largest cost difference in the category and the only one that grows with you.
• Score or placement. A warmup score measures the tool's own network. A spam placement test sends to real seed inboxes at Gmail, Outlook, and Yahoo and reports where mail landed. Only some tools do the second.
• Which mailboxes it connects. Google and Microsoft are universal. Plain SMTP, self hosted, and less common providers are not, and that decides whether one tool can cover every mailbox you run.
• Whether you already have it. Check your sending platform before you buy anything. A second warmup subscription on top of bundled warmup is pure waste.

Built in warmup: Smartlead, Instantly, lemlist, Salesforge

Start here, because for most senders this is the whole answer. If you send through one of the major platforms, warmup is already included in what you pay.

Pricing. Smartlead runs from $39 a month on Base to $379 on Unlimited Prime, with unlimited email accounts and warmup included at every tier. lemlist starts at $69 a month billed monthly, or $55 a month billed annually, with lemwarm included. Instantly and Salesforge bundle warmup into their plans as well.

Pros

• No separate subscription, and no per inbox warmup fee at any scale.
• It runs inside the tool your mailboxes already live in, so nothing to reconnect when a mailbox changes.
• Warmup volume and campaign volume are managed in one place, which makes the ramp easier to keep sane.

Cons

• You are trusting the sender to grade its own deliverability, which is exactly the conflict described above.
• If you run mailboxes across several platforms, bundled warmup covers only the ones inside each platform.
• Switching sending tools means switching warmup, and the reputation history stays with the domain rather than the dashboard.

Verdict. If your platform bundles warmup, use it, and spend the money you saved on list verification or monitoring instead. Buy standalone only for a specific reason, not by default.

Warmup Inbox

The standalone tool we link to, and the one worth judging hardest because of that.

Pricing. Basic is $15 per inbox per month with 75 warmup emails a day. Pro is $49 per inbox with 250 a day. Max is $79 per inbox with 1,000 a day. Reply rates inside the network are capped by tier too, so the plan you pick changes how the warmup behaves, not just how much of it you get.

Pros

• Connects Google, Microsoft, and standard SMTP inboxes, so it can cover mailboxes that sit outside your main sending tool.
• Runs independently of your sender, which is useful when you are warming domains before you have chosen a platform, or when you want a warmup layer that survives a platform switch.
• Reporting shows where warmup mail is landing rather than only a single health number.

Cons

• Per inbox pricing scales in a straight line. Ten inboxes on Basic is $150 a month for warmup alone, and twenty is $300.
• The daily caps and reply rate limits are the upsell path, so heavier warmup means the $49 or $79 tier rather than a volume discount.
• It solves the same job your sending platform may already solve for free.

Verdict. A sensible pick for a handful of mailboxes you want warmed independently of your sender, and for mixed setups where one warmup layer has to cover several platforms. It is not the cheapest way to warm 20 client inboxes, and we are not going to pretend otherwise. You can try Warmup Inbox here.

TrulyInbox

The clearest answer to the per inbox pricing problem.

Pricing. A free plan covers one email account at 10 warmup emails a day with no time limit. Paid plans price by daily warmup volume rather than by inbox: Starter $29 a month for 200 a day, Growth $99 for 1,000 a day, Scale $199 for 3,000 a day, and Scale+ tiers from $479 for 5,000 and up. Paid plans state unlimited email accounts. Annual billing is cheaper, and paid tiers come with a 7 day trial without a card.

Pros

• Unlimited mailboxes on every paid plan, which is the single biggest cost saver for an agency roster.
• A genuinely free tier, so you can warm one domain at low volume without a card.
• Volume based pricing means your bill tracks how much warmup you actually use.

Cons

• The daily volume cap becomes the constraint instead of the inbox count, so a large roster on Starter runs thin fast.
• Less brand recognition than the older names, which matters if a client asks what you use.
• Warmup network quality is not something any vendor lets you audit, here or anywhere else.

Verdict. If you are paying per inbox today and run more than about five mailboxes, run the flat rate maths before your next renewal. This is where the saving is.

MailReach

The one that answers a different question: not "is my warmup running" but "where is my mail actually landing."

Pricing. $19.50 per mailbox per month on monthly billing, with 20% off annual and volume discounts up to 100 mailboxes. Every warmer plan includes at least 20 spam test credits. Extra spam test credits are sold separately, and pricing over 100 mailboxes goes to a quote. MailReach is a European vendor and may show the figure in euros depending on your region, so check the currency on the toggle.

Pros

• Warmup and real spam placement testing in one subscription, which is the pairing most senders should want.
• Placement tests measure real seed inboxes rather than the tool's own network, so the number means something outside the dashboard.
• Volume discounts exist, which softens the per mailbox model at scale.

Cons

• Still per mailbox, so it is not the cheap option for a large roster.
• Spam test credits are a second line item once you test regularly.
• Two products in one plan means you pay for testing even if you only wanted the warmer.

Verdict. The best pick if you want proof of placement attached to your warmup, especially before scaling a campaign. See the deliverability tools overview for where placement testing sits in the wider stack.

Warmforge

The easiest way to warm one domain for nothing, from the team behind Salesforge.

Pricing. $10 a month per warming slot, with one slot free. Quarterly billing knocks about 10% off and annual billing is advertised as two months free. Placement testing is a separate product: Pro at $39 a month for 100 tests, Growth at $169 a month for unlimited tests.

Pros

• One free warming slot, so you can warm a single domain at no cost indefinitely.
• $10 per slot month to month, with no annual commitment. Mailwarm is cheaper per inbox but wants a year up front.
• Placement testing is available from the same vendor when you need it.

Cons

• Still a per slot model, so 20 mailboxes is $200 a month before any testing.
• Placement testing is priced separately rather than bundled like MailReach.
• Newer product than most on this list, with a shorter public track record.

Verdict. The best value if you are warming one to five inboxes and do not have bundled warmup. The free slot alone makes it worth testing before you pay anyone.

Warmbox

Straightforward plans with the inbox count printed on them.

Pricing. On monthly billing, Solo is $19 for 1 inbox at 50 emails a day, Start-up is $79 for 3 inboxes at 250 a day, and Growth is $159 for 6 inboxes at 500 a day. Annual billing drops those to $15, $69, and $139. Custom plans exist for larger volumes.

Pros

• Plans bundle a set number of inboxes, so the monthly bill is predictable.
• Clean, simple product with little to configure, which suits a small team.
• Annual billing is a real discount rather than a rounding error.

Cons

• Bundled inbox counts are small, so growth means a tier jump rather than a small increase.
• No placement testing included, so you are back to trusting a score.
• Effective cost per inbox on the entry plan is higher than Warmforge or Warmup Inbox.

Verdict. Fine for a small team that wants one predictable line item. Less compelling once your inbox count stops matching the tier boundaries.

Lemwarm

Free if you already pay for lemlist, and priced against a different market if you do not.

Pricing. Included in every lemlist plan at no extra cost, and lemlist starts at $69 a month billed monthly or $55 a month billed annually. Lemwarm is also sold standalone, but the standalone tiers are not shown on the main pricing page, so check current pricing before you budget for it.

Pros

• Genuinely free for lemlist customers, which makes it the obvious choice if you already send through lemlist.
• Mature product with a large warmup network behind it.
• Deliverability checks and reporting sit alongside the warmer rather than in a separate tool.

Cons

• Standalone pricing is not transparent on the pricing page, which makes it hard to compare without a sales step.
• If you are not a lemlist customer, you are paying for a warmer priced above the cheapest options here.
• Tied to the lemlist ecosystem, so it is a weaker fit for mailboxes spread across other platforms.

Verdict. Use it if you use lemlist. If you do not, the standalone case is harder to make against Warmforge or TrulyInbox.

Mailwarm

One of the older names in the category, aimed at senders who want to shape the warmup themselves.

Pricing. Basic is $90 per year for 50 inboxes at up to 40 emails per inbox per day. Pro is $190 per year for unlimited inboxes at up to 80 per day. Both are billed yearly, both include peer to peer sending and human review, and the page carries a monthly toggle as well.

Pros

• On a per inbox basis this is the cheapest option here by a wide margin. Fifty inboxes on Basic works out at $1.80 per inbox per year.
• Pro removes the inbox cap entirely, which is unusual at this price.
• Long running product with an established network.

Cons

• Priced annually, so it is a year up front rather than a month you can cancel.
• Forty emails per inbox per day on Basic is a ceiling worth checking against your ramp.
• More configuration than most senders need, and misconfigured warmup is worse than none.

Verdict. Only worth a call if the hand tuned schedule solves something specific for you. Otherwise the transparent options above are easier to buy and easier to budget.

Warmy

The most service heavy option, and now the least transparent on price.

Pricing. Warmy no longer publishes prices. The pricing page splits into B2B sender, B2C sender, and custom plans, all of which route to a demo booking, with volume based pricing and a 7 day trial. Check current pricing on a call, and be aware that per inbox volume pricing at this end of the market gets expensive quickly on a large roster.

Pros

• Google Postmaster integration and a deliverability monitor sit alongside the warmer.
• A named deliverability expert is included rather than sold as consulting.
• Separate handling for B2C sending, which most cold email warmup tools ignore.

Cons

• No public pricing, so you cannot compare it against anything without a sales call.
• The service layer is the reason for the price, and a lot of senders will not use it.
• Volume based per inbox pricing is the model that hurts most at agency scale.

Verdict. Worth a demo if you want a person attached to your deliverability and have the budget for it. Skip it if you just need a warmer.

Which warmup tool should you pick

The right answer depends almost entirely on how many mailboxes you run and whether you already pay for warmup.

• Solo sender already using a platform. Use the bundled warmup in Smartlead, Instantly, lemlist, or Salesforge and buy nothing. A second warmup subscription buys you a second dashboard, not better placement.
• Solo sender with no bundled warmup, one to five inboxes. Warmforge, because the first slot is free and additional slots are $10. TrulyInbox's free plan is the alternative if one inbox at low volume is enough.
• Mixed setup across several sending tools. Warmup Inbox, because it connects Google, Microsoft, and plain SMTP and gives you one warmup layer across mailboxes that live in different platforms.
• Agency running 10 or more client inboxes. Flat rate or bundled, never per inbox. Mailwarm Pro is the cheapest unlimited option at $190 a year, if you are willing to pay annually. TrulyInbox from $29 a month is the alternative when you want to stay month to month, and bundled warmup inside whichever platform your clients sit on is free. Per inbox pricing at this scale costs hundreds a month for a commodity service.
• High volume sender who needs proof, not a score. MailReach, because the spam placement tests are in the plan. Warmforge's separate placement tiers are the alternative if you already warm there.
• Anyone whose authentication or list is broken. No warmup tool. Fix SPF, DKIM, and DMARC and clean the list first, or you are warming a domain you are about to burn anyway.

The part no warmup tool covers

Every tool on this page does the same underlying thing: it sends mail into a network it owns and reports on what happens inside that network. That is a setup job with an end date.

The failure that actually costs money happens later. A domain that warmed cleanly starts sliding in week six. A mailbox quietly drops out and stops delivering. A client's replies thin out over a fortnight and nobody notices until they ask why. None of that shows up in a warmup dashboard, because the warmup network is not where your campaigns live.

So whatever you pick, make sure something is watching placement, bounce trends, and mailbox health across live sending afterwards. ColdOps does that across every client workspace and raises an alert the day something breaks. If you run one or two domains, a disciplined weekly look at reply and bounce rates per client covers the same ground.

Rules that matter more than which tool you buy

• Start low and ramp slowly. A handful of sends per mailbox per day at first, climbing over two to three weeks. The full warmup walkthrough has the schedule.
• Never flip a new domain to full volume on day one. The single most common way new senders end up in the spam folder.
• Keep warmup running after launch. It is a background habit, not a one time task. Trim it as real engagement grows.
• Watch placement, not the warmup score. Send yourself a plain test to the domain and confirm it lands in the inbox. Our free deliverability checker tests auth, blacklists, and domain health in one pass while you warm up.
• Keep the ramp matched to your real volume. The sending volume guide covers the ceiling per mailbox once you are warm.

Warmup is a commodity. Pick the pricing model that fits your inbox count, keep it light, and put your attention on the domains that carry the revenue.