7 Best Email Warmup Tools for Cold Email Outreach

The best email warmup tool depends on your sending stack. BrandJet is our first pick when warmup belongs in a broader multichannel outreach workflow. Instantly and Smartlead fit teams buying warmup alongside their email sequencer. MailReach, Warmup Inbox, lemwarm, and Warmbox offer standalone options.

Compare pricing, controls, and provider access first. Automated warmup generates interactions, but it cannot guarantee that prospecting emails will reach the primary inbox.

Table of Contents

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Which Email Warmup Tool Should You Choose?

Tool	Best Fit	How You Pay	Watch Out For
BrandJet	Teams combining email warmup, prospecting, and multichannel outreach	Broader platform subscription	Not a standalone spam-testing service
Instantly	Teams sending campaigns through Instantly	Outreach subscription with warmup included	Campaign send and contact limits still apply
Smartlead	Agencies managing many connected mailboxes	Outreach subscription with warmup included	Pool tiers and campaign allowances vary by plan
MailReach	Dedicated warmup plus spam testing	Per mailbox, with volume pricing	Larger deployments need a confirmed price
Warmup Inbox	Standalone warmup with an accessible entry tier	Per inbox, with quantity discounts	Pausing warmup does not cancel billing
lemwarm	Standalone users or teams already on lemlist	Per email address, or bundled with lemlist	Bundled and standalone entitlements differ
Warmbox	Small setups with defined inbox allowances	One, three, or six inbox plans; custom above that	Verify the connection method and larger-team quote

If your sequencer includes suitable warmup, avoid buying it again. Otherwise, a standalone tool lets you keep your current sending workflow.

Compare Warmup Controls, Plan Limits, and Billing

1. BrandJet: Best for Warmup Within a Multichannel Outreach Workflow

BrandJet combines warmup with lead sourcing, email outreach, follow-ups, and other channels. It advertises warmup as included in every plan.

For an account with warmup already active, open Accounts > Warmup > View. The account’s Warmup tab shows its session and a Pause Warmup action. Open Settings to review timezone, start and end hours, Starting Emails/Day, Daily Increase, Maximum Emails/Day, and Reply Rate (%).

Reply Rate (%) governs warmup interactions, not prospect replies. Although BrandJet describes a warmup network, pool selection should not be assumed.

Pricing: BrandJet Starter is listed at $79 monthly, with two months free on annual billing, equivalent to approximately $65.83 per month. Its published plans include unlimited inboxes, though mailbox hosting and provider restrictions remain separate considerations. Confirm the relevant plan entitlement before buying solely for warmup.

Explore BrandJet email warmup for a bundled workflow. These controls do not establish inbox placement outcomes.

Choose BrandJet when warmup, listening signals, and multichannel follow-up need to sit in one broader workflow. If you only need a standalone spam-testing service, compare a specialist instead.

2. Instantly: Best for Cold Email Sending and Warmup Together

Instantly’s Outreach Growth plan includes unlimited connected accounts and warmup. Its settings cover daily limits, gradual increases, and warmup reply percentages, with bulk editing across accounts.

Instantly-managed AirMail mailboxes instead use noneditable dynamic warmup settings.

Pricing: Outreach Growth is listed at $47 monthly, or $37.60 per month equivalent when billed annually. It also includes 5,000 campaign emails per month and 1,000 uploaded contacts. Unlimited connected inboxes are not unlimited campaign sends.

Choose it if you need both warmup and sequences, not if you only need an add-on to an existing sequencer.

3. Smartlead: Best for Agencies With Many Sending Inboxes

Smartlead includes unlimited connected accounts and warmup. Base, Pro, and higher plans have different warmup pool tiers.

Agencies can manage warmup and sequences together, but the entry tier does not include unlimited sending.

Pricing: Base starts at $39 monthly, or approximately $32 per month equivalent with annual billing. It includes 6,000 campaign emails per month and storage for 2,000 contacts. Higher volume and certain agency or API features require other plans or add-ons.

Choose it for mailbox management, after checking send allowances and workspace requirements.

4. MailReach: Best for Warmup With Spam Testing

MailReach combines warmup with spam tests, inbox health checks, and reporting. It fits teams keeping their existing sequencer but needing additional diagnostics.

A spam test samples placement; it does not predict delivery to every prospect.

Pricing: Its All-in-One calculator starts at $25 per mailbox monthly, or $20 per mailbox per month with annual billing. With 20 included spam-test credits, the displayed total is $195 monthly for ten mailboxes and $900 for fifty. Annual-billing equivalents are $156 and $720 per month respectively. Extra test credits change the total.

Choose it when separate testing matters. It is not a sequencer.

5. Warmup Inbox: Best for Standalone Warmup With Clear Entry Pricing

Warmup Inbox offers standalone warmup and monitoring. Basic includes daily activity and reports; higher tiers add custom content, scheduling, and provider-specific settings.

It advertises Google Workspace, Microsoft 365, and other integrations; check the actual authentication route.

Pricing: Basic starts at $19 per inbox per month, or $15 per inbox per month with annual payment. Its live quantity selector displays $160 per month for ten inboxes and $475 for fifty on monthly billing. The corresponding annual-billing equivalents are $125 and $375 per month. Those volume discounts make entry-rate multiplication misleading.

One practical warning: pausing an inbox stops its warmup activity but does not cancel the subscription. Cancellation is a separate billing action.

Choose it for standalone warmup if per-inbox billing fits.

6. lemwarm: Best for lemlist Users or Standalone Buyers

lemwarm offers standalone Essential and Smart tiers. Essential provides warmup, technical checks, and reports. Smart adds personalized content and tailoring, without proven placement superiority.

Pricing: Standalone Essential starts at $29 per email address monthly, or $24 per month equivalent annually. Smart starts at $49 monthly, or $40 annually per address. Larger teams can request custom pricing.

Alternatively, lemlist Email includes warmup and advertises unlimited email senders. It starts at $69 monthly, or $55 monthly equivalent annually, subject to its sending limits. Compare this bundle before multiplying standalone rates across many inboxes.

If you already subscribe to lemlist, check your included entitlement first.

7. Warmbox: Best for Small Teams With Defined Inbox Allowances

Warmbox describes automated interactions, scheduling, and activity controls, with explicit inbox allowances.

Pricing: Solo covers one inbox at $19 monthly or $15 per month equivalent annually. Start-up covers three inboxes at $79 monthly or $69 annually. Growth covers six at $159 monthly or $139 annually. Larger requirements use a custom Team arrangement.

Warmbox documents Gmail connections using app passwords. Your organization may require OAuth or prohibit app passwords; published compatibility is not provider approval.

For ten or fifty inboxes, get a Team quote.

How Much Does Email Warmup Cost for 1, 10, or 50 Mailboxes?

These USD figures cover software subscriptions only. Each pair means monthly billing / monthly equivalent when billed annually. Annual pricing requires a longer commitment. MailReach figures use All-in-One with 20 included spam-test credits; extra credits cost more.

Tool and Purchase Route	1 Mailbox	10 Mailboxes	50 Mailboxes
BrandJet Starter	$79 / $65.83	$79 / $65.83	$79 / $65.83
Instantly Outreach Growth	$47 / $37.60	$47 / $37.60	$47 / $37.60
Smartlead Base	$39 / $32	$39 / $32	$39 / $32
Warmup Inbox Basic	$19 / $15	$160 / $125	$475 / $375
MailReach All-in-One	$25 / $20	$195 / $156	$900 / $720
lemwarm Essential, standalone	$29 / $24	Confirm volume price	Custom quote
Warmbox	$19 / $15, Solo	Team quote	Team quote
lemlist Email, with bundled lemwarm	$69 / $55	$69 / $55	$69 / $55

Flat-rate rows reflect advertised inbox allowances, not equal campaign capacity. Confirm BrandJet’s plan entitlement, lemlist’s warmup level, and actual volume discounts.

One Mailbox: Compare the Tool With What You Already Own

With one existing mailbox and a separate sequencer, Warmup Inbox Basic and Warmbox Solo each list $19 monthly. Check connection permissions and reporting before paying for another outreach platform.

Ten Mailboxes: Apply the Same Billing Basis

For ten inboxes, Warmup Inbox Basic’s displayed monthly rate is $16 per inbox, totaling $160 per month. On annual billing it is $12.50 per inbox per month, totaling $125 per month equivalent, or $1,500 billed yearly.

MailReach’s ten-mailbox All-in-One total is $195 on monthly billing or $156 per month equivalent annually with the included test-credit setting. Compare the diagnostic features and mailbox permissions, not just the difference between those totals.

Instantly Growth and Smartlead Base include multiple accounts but cap campaign sends. Compare higher plans if ten inboxes exceed those allowances.

Fifty Mailboxes: Budget Beyond the Warmup Subscription

At fifty inboxes, Warmup Inbox Basic displays $475 per month, or $375 per month equivalent annually. MailReach All-in-One displays $900 per month, or $720 per month equivalent annually, with 20 included spam-test credits. Treat these as configured software prices, not comparable inbox-placement results.

Bundled prices exclude mailbox hosting, domains, possible extra workspaces, data, and verification. Combined campaign and warmup traffic also matters for provider limits.

For example, hypothetically, 20 campaign messages plus 10 outgoing warmup messages from the same mailbox mean 30 outgoing messages that day. That is arithmetic, not a recommended sending limit. For managing campaign distribution separately, compare cold email inbox rotation tools.

Check Provider Access Before Connecting a Mailbox

Google Workspace, Microsoft 365, or SMTP compatibility does not establish administrator approval.

Before authorizing it, check whether it uses OAuth or credentials such as an app password, what mailbox permissions it requests, and whether your provider and organization permit the intended automated activity. OAuth access can include sending or reading messages, depending on the scopes granted. Google generally recommends sign-in authorization over app passwords where supported.

Connection success is not provider endorsement. Warmup does not override Google or Microsoft rules.

Also plan your exit before connecting: pausing warmup, disconnecting a mailbox, revoking its authorized access, and canceling billing are four different actions. If the vendor retained a copy of mailbox data, credential revocation alone may not delete it.

What Can Warmup Results Actually Tell You?

A warmup dashboard can tell you how the tool’s own messages and interactions are behaving. Its reply-rate setting describes responses within that warmup system. It does not measure how interested prospects are in your offer.

Likewise, a seed-based spam test samples placement under particular conditions. The results may point to issues, but they do not establish the inbox placement percentage of your next campaign.

Monitor authentication, bounces, deferrals, complaints where available, and list quality. Warmup does not repair SPF, DKIM, or DMARC errors or unwanted outreach.

For the broader checks that matter beyond warmup, see how to improve cold email deliverability.

When Should You Skip a Separate Warmup Subscription?

Skip a second subscription if your current platform covers warmup, provider support, and controls. Consider standalone software when independent testing or reporting warrants its cost and access.

If you cannot approve the requested mailbox permissions, or your actual problem is authentication, list quality, or complaints, address that first. Paying for more warmup interactions is not a replacement for fixing the cause.

FAQ

What Is the Best Email Warmup Tool for Cold Email Outreach?

BrandJet is our pick when warmup belongs inside a broader prospecting and multichannel workflow. Instantly and Smartlead make sense when you also need their email outreach software. MailReach, Warmup Inbox, lemwarm, and Warmbox serve buyers who want a dedicated route. Compare connection methods, costs, and controls rather than advertised placement percentages.

Do I Need a Separate Email Warmup Tool If I Use Instantly or Smartlead?

Usually not if the included warmup supports your mailboxes and operating requirements. Both platforms advertise warmup without a separate per-mailbox warmup charge. An additional service could still make sense for independent diagnostics or a specific feature, but check the overlap before paying for it.

How Much Does Email Warmup Cost for 10 or 50 Mailboxes?

Bundled outreach tools may keep their software subscription price unchanged as you connect more inboxes, while standalone services often charge per mailbox and offer discounts. The total also depends on hosting, domains, campaign allowances, and billing term. Use ten and fifty mailbox quotes rather than assuming an entry rate applies unchanged.

Is Email Warmup Safe to Use With Google Workspace or Microsoft 365?

No product can provide a blanket safety guarantee. Check the provider’s current sending policies, the account’s permitted connection method, administrator approval, and the permissions requested. Automated warmup activity may be subject to restrictions even when the connection succeeds. Do not treat vendor compatibility claims as provider approval.

Does Email Warmup Guarantee Better Inbox Placement?

No. Warmup networks generate interactions with participating inboxes, which differ from genuine prospect traffic. Spam tests sample particular destinations. Neither establishes a guaranteed placement rate for real campaigns. Authentication, sender history, content, recipient behavior, complaints, and sending practices still matter.

How Long Should You Warm Up a New Email Account Before Sending Cold Emails?

There is no universal duration that makes a mailbox safe for cold outreach. Start with correct authentication, follow the provider’s policies, and increase legitimate sending gradually rather than making abrupt jumps. Monitor delivery and complaint indicators. Be skeptical of any tool promising guaranteed readiness after a fixed number of weeks.

Can I Send Cold Emails While My Mailbox Is Warming Up?

You can run campaign and warmup activity concurrently where your provider and account rules allow it. Count the combined outgoing traffic when checking limits and scheduling. Gradual sending does not mean there is a universal safe daily quota. Pause or adjust activity if delivery problems or provider restrictions appear.

How Do I Stop Email Warmup and Remove a Tool’s Access to My Inbox?

First pause its automated activity, then disconnect the mailbox from the service. Next, revoke the relevant OAuth authorization or app password in your email provider. Finally, cancel or change the subscription separately and check whether the vendor retains data. A pause button alone may leave access and billing active.