Best Email Warmup Tools for Agencies (2026)
The five email warmup tools worth comparing for Agencies in 2026, with prices read off each vendor's own pricing page and an honest read on fit.
The best email warmup tools for Agencies in 2026 are TrulyInbox, Mailreach, InboxAlly, Lemwarm and Warmbox. TrulyInbox publishes a free plan and then $29/mo, Warmbox starts at $15 a month yearly, Mailreach charges $19.5 per mailbox, and InboxAlly starts at $149. For agencies, the deciding factor is what an extra mailbox costs across a roster.
Key takeaways
- An agency's mailbox count is clients multiplied by inboxes per client, so a per-mailbox charge turns correct per-client isolation into the most expensive way to operate.
- The five tools bill on five different units: warmup emails per day (TrulyInbox), per mailbox (Mailreach), seed emails and sender profiles (InboxAlly), per email address (Lemwarm) and a fixed inbox cap (Warmbox).
- TrulyInbox publishes a free forever plan for 1 account at 10 warmup emails/day, then $29/mo paid monthly, and connects unlimited accounts on every paid plan.
- Warmbox Solo is published at $15 /month on yearly billing for 1 inbox warm-up, and Mailreach publishes $19.5 / mailbox Per Month, so the cheaper option flips as soon as inbox count rises.
Reviewed and updated August 28, 2026
Best Email Warmup Tools for Agencies (2026)
An agency warming inboxes for ten clients is carrying ten separate reputations on one subscription. The pricing unit is therefore not a detail, it is the margin: a per-mailbox charge multiplied across a client roster is the difference between a profitable outbound service line and one that quietly is not.
What Agencies Need From a Email Warmup Tool
- Multi-client management
- White-label options
- Bulk operations
- Reporting per client
Unit economics decide this purchase. Every client needs its own domains and its own inboxes, so an agency's mailbox count is client count multiplied by inboxes per client, and that product grows fast. A tool that charges per mailbox turns correct per-client isolation into the most expensive way to operate, while one that charges for warmup volume across unlimited accounts absorbs it.
Bulk operations follow directly. Onboarding a client means adding and warming a set of mailboxes, and doing that by hand across a roster is where the delivery margin goes. Judge these tools on how quickly a new client's inboxes can be added, because that is the operation an agency performs most often.
Per-client reporting is the commercial requirement rather than an operational one. An agency has to show a client its own deliverability without exposing anyone else's, and it needs to see a single client's domain drifting before that client does.
How This Guide Was Put Together
Every price, plan name, inbox cap and volume limit here was read off the vendor's own pricing page, from a dated snapshot taken while the guide was written, and each figure is attributed to the page it came from rather than to the vendor in general. Where a figure comes from a different surface, the text says so.
No lab test sits behind this. Nobody here ran a controlled warmup across five platforms, so the guide makes no claim about which tool produces the best inbox placement. What it does judge is the pricing model, the capacity limits, and which shape of sending operation each set of published plans was drawn for.
Top 5 Email Warmup Tools for Agencies
- Unlimited email accounts on every paid plan
- Priced on warmup emails per day, not inboxes
- Reply rate rising from 25% to 65% by tier
- and 5 more listed below
- Smart AI warming algorithm with dozens of parameters
- 20 spam test credits included with the warmer
- Blacklist, SPF, DKIM and DMARC monitoring
- and 5 more listed below
- Real seed-inbox engagement rather than a peer network
- 100 to 1,000 seed emails a day by tier
- 10-day free trial with no card
- and 5 more listed below
1. TrulyInbox
Warmup platform priced on the emails you send rather than the accounts you connect, with adaptive sending patterns, AI-written warmup content and per-mailbox scoring.
From the TrulyInbox pricing page: free forever for 1 account at 10 warmup emails/day, up to $479/mo paid monthly on Scale Plus, above which the plan is quoted as Custom.
| Plan (TrulyInbox pricing page) | Billed annually | Paid monthly | Warmup emails/day | Reply rate |
|---|---|---|---|---|
| Free | Free forever, 1 account | Free | 10 | |
| Starter | $22/mo, $264/year | $29/mo | 200 | up to 25% |
| Growth | $84/mo, $1,008/year | $99/mo | 1,000 | up to 45% |
| Scale | $169/mo, $2,028/year | $199/mo | 3,000 | up to 60% |
| Scale Plus | $407/mo, $4,884/year | $479/mo | 5,000 | 65% |
Two things there matter more than the prices. It states Unlimited Accounts on every paid plan, describing its model as pay for emails sent, not accounts connected, the opposite of how the rest of this list bills. And it publishes the sizing rule: warmup runs on a 2:1 ratio, two warmup emails per cold email, ongoing. That is the number to take away whichever tool you buy.
Key Features:
- Unlimited email account connections on all paid plans
- Customizable email ramp-up schedules
- AI adaptive warmup strategy
- Human-like email interaction simulation
Integrations: Gmail, Google Workspace, Outlook, Microsoft 365, Zoho Mail, SMTP, Yahoo Mail
The strongest fit for agency economics, because its page connects unlimited accounts and prices on warmup emails per day, so onboarding a client adds mailboxes without adding a line to the bill. API access on the published plans is what makes bulk onboarding practical.
2. Mailreach
Warmup and deliverability platform that drives positive engagement signals with a multi-parameter algorithm, bundled with spam testing and DNS monitoring.
From the Mailreach pricing page: $19.5 per mailbox, per month, and above 100 mailboxes that page stops naming a number and quotes custom pricing.
| Mailreach pricing page | Published figure |
|---|---|
| Warmup rate | $19.5 / mailbox Per Month |
| Annual billing | Save 20% |
| Mailbox slider | 1, 20, 40, 60, 80, 100+ |
| Included with the warmer | 20 spam test credits |
| Sending ceiling | Up to 100 emails per day |
That page is a calculator rather than a plan ladder, so its running totals depend on where the sliders sit and no single price is what a visitor always sees. The per-mailbox rate survives every slider position, which is why it is the figure quoted here.
Key Features:
- Smart AI warming algorithm with dozens of parameters
- Automated spam testing with 20+ credits included
- MailReach Co-Pilot AI deliverability assistant
- Blacklist, SPF, DKIM, and DMARC monitoring
Integrations: Gmail, Google Workspace, Outlook, Microsoft 365, Zoho, SMTP, Mailgun, SendGrid (+1 more)
At the published $19.5 per mailbox the arithmetic is clear and it is the shape that hurts an agency most, since the unit is exactly the thing that multiplies across a roster. Above 100 mailboxes that page moves to custom pricing, which is where an agency of any size lands.
3. InboxAlly
Deliverability platform that trains inbox placement using its own seed inboxes, which open, read and reply to your mail rather than exchanging it with other senders.
From the InboxAlly pricing page: $149 / month billed monthly, up to $1,190 / month on Premium, with Enterprise quoted as Contact us.
| Plan (InboxAlly pricing page) | Price | Seed emails per day | Sender profiles |
|---|---|---|---|
| Starter | $149 / month | 100 | 1 |
| Plus | $645 / month | 500 | 5 |
| Premium | $1,190 / month | 1,000 | 10 |
| Enterprise | Contact us | Custom volume | Unlimited |
That page publishes no annual discount, prices everything billed monthly, and offers a free trial of 10 days with no credit card required. The seed model explains the price gap: you are buying inboxes the vendor controls rather than a slot in a peer network.
Key Features:
- Real seed email engagement (opens, replies, scroll depth)
- SmartRank optimization with per-ISP reputation scoring
- Inbox simulation mimicking genuine user behavior
- Custom content control for warmup emails
Integrations: Gmail, Google Workspace, Outlook, Microsoft 365, SendGrid, Mailgun, Amazon SES, SMTP (+1 more)
Published with workspaces for multi-account switching and a dedicated CSM at every tier, which is genuinely agency-shaped, but from $149 / month for 1 sender profile it is priced per client rather than per roster. Use it for a specific client with a damaged domain.
4. Lemwarm
Warmup tool from lemlist that builds sender reputation across a network of real inboxes, with a technical setup check and a daily deliverability score.
From the Lemwarm pricing page: $24 per email address per month yearly or $29 monthly, up to $40 yearly or $49 monthly, above which teams of more than 10 users are quoted Custom.
| Plan (Lemwarm pricing page) | Yearly | Monthly | Priced per |
|---|---|---|---|
| Essential Plan | $24 | $29 | PER EMAIL /month |
| Smart Plan | $40 | $49 | PER EMAIL /month |
| Custom | Contact sales | Contact sales | More than 10 users |
The per-address unit is the detail to carry into a budget, because those figures read like a team price and are not. That page also offers Quarterly billing at Save 10% against Yearly at Save 20%, and states that every lemlist plan includes lemwarm, so check what you already own before buying separately. Lemwarm's homepage sizes the warm-up network at 20,000+ healthy domains in 100+ countries.
Key Features:
- Automatic email warm-up with human warm-up emails
- Warm-up network of 20k+ healthy domains
- Warm-up network tailored to your industry
- Technical setup check and deliverability reports
Integrations: Gmail, Google Workspace, Outlook, Microsoft 365, SMTP, lemlist (native), HubSpot (via lemlist), Salesforce (via lemlist) (+1 more)
PER EMAIL /month across a client roster is the least favourable unit here, and its Custom tier begins above 10 users. Relevant where an agency has standardised its clients on lemlist, whose plans that page says include lemwarm.
5. Warmbox
Warmup tool with fixed plans, customizable recipes, spam-score monitoring and a reporting dashboard, covering a wide spread of mailbox providers.
From the Warmbox pricing page: $15 /month on yearly billing or $19 /month monthly, up to $139 /month yearly or $159 /month monthly, above which Team plans are quoted Contact Us.
| Plan (Warmbox pricing page) | Yearly billing | Monthly billing | Inboxes | Emails/day | Members |
|---|---|---|---|---|---|
| Solo | $15 /month | $19 /month | 1 inbox warm-up | 50 emails/day | 1 |
| Start-up | $69 /month | $79 /month | 3 inbox warm-up | 250 emails/day | 3 |
| Growth | $139 /month | $159 /month | 6 inbox warm-up | 500 emails/day | 6 |
| Team | Contact Us | Contact Us | Custom | Custom | Custom |
The inbox cap decides whether Warmbox is cheap or unusable for you: Growth is the largest named plan on that page and covers 6 inboxes. A team running more than that is into Contact Us territory whatever the headline suggests, which is a very different position from the tools here that connect unlimited accounts.
Key Features:
- Automated email warm-up with AI-powered interactions
- Customizable warmup recipes and strategies
- Spam score monitoring and blacklist checks
- Real-time analytics and reporting dashboard
Integrations: Gmail, Google Workspace, Outlook, Microsoft 365, Yahoo Mail, Amazon SES, SMTP, Zoho Mail
Its largest named plan covers 6 inbox warm-up, which is roughly one client. An agency would be buying a subscription per client, which is worth pricing but rarely wins.
The Five Tools Price on Five Different Units
Comparing headline prices across warmup tools is close to meaningless, because no two of these five charge for the same thing.
| What you are actually billed for (from each vendor's pricing page) | Tool |
|---|---|
| Warmup emails sent per day, with unlimited accounts connected | TrulyInbox |
| Each mailbox warmed, per month | Mailreach |
| Seed emails per day and sender profiles | InboxAlly |
| Each email address, per month | Lemwarm |
| A plan with a fixed inbox cap | Warmbox |
A team with 40 inboxes sending lightly is cheapest on the tool that ignores inbox count; the same team sending hard is cheapest on the one that ignores volume. Work out both numbers before comparing any prices.
Comparison Table
| Tool (figures from its own pricing page) | Entry price | Free option |
|---|---|---|
| TrulyInbox | Free, then $29/mo monthly | Free forever, 1 account |
| Mailreach | $19.5 / mailbox Per Month | No |
| InboxAlly | $149 / month | 10-day free trial |
| Lemwarm | $24 yearly, $29 monthly | No |
| Warmbox | $15 /month yearly, $19 monthly | No |
Recommendation by Budget
Starting at nothing. The TrulyInbox pricing page publishes a free forever plan for 1 account at 10 warmup emails/day, the only ongoing free plan on this list.
The cheapest paid tiers. Warmbox Solo is published at $15 /month yearly and $19 /month monthly for 1 inbox warm-up; Lemwarm Essential Plan at $24 yearly and $29 monthly PER EMAIL /month; TrulyInbox Starter at $22/mo annually and $29/mo monthly for 200 warmup emails/day across unlimited accounts.
The middle, where the unit bites. Mailreach publishes $19.5 / mailbox Per Month, so ten mailboxes costs roughly ten times one, while TrulyInbox Growth is published at $84/mo annually and $99/mo monthly for 1,000 warmup emails/day whatever the inbox count. Those two diverge in opposite directions as a team grows.
The upper published tiers. InboxAlly starts at $149 / month for 100 seed emails per day, with $645 and $1,190 named above it, and TrulyInbox Scale is published at $169/mo annually and $199/mo monthly.
How to Choose
What does an additional mailbox cost? Multiplied across a roster this is the single largest determinant of whether the service line is profitable.
How fast can a client be onboarded? Adding and warming a set of mailboxes is the operation you will perform most. Time it during the trial, including through an API if there is one.
Can client reputations be isolated? Separate domains and separate inboxes per client, always. Confirm the tool enforces the separation rather than merely permitting it.
Does reporting segment per client? A client report must show that client and nothing else, and you need to see one client's domain drifting before they do.
Does the pricing shape match the retainer? Volume pricing inside a fixed retainer transfers risk to the agency, so price the retainer against expected warmup volume or choose a model that does not move with it.
Warming Without Wasting the Month
- Step 1Separate domains
Buy outbound domains that carry no client, product or transactional mail, and attach only those
- Step 2Authenticate
Fix SPF, DKIM and DMARC first, because warmup cannot compensate for a domain that fails them
- Step 3Warm at low volume
Weeks of steady sending history at the published 2:1 ratio, two warmup emails per cold email
- Step 4Send, still warming
Keep the warmup running once campaigns start, and send one message per campaign
Build the per-client architecture before the first campaign: dedicated domains per client, inboxes attached to those domains, and warmup running on all of them from onboarding rather than from launch.
Build the warmup lead time into the onboarding schedule and tell the client about it. An agency that promises campaigns in week one and spends weeks three and four explaining poor placement has sold the wrong timeline; the honest version is that warmup starts on day one and sending starts later.
One message per campaign, across every client. The reputation a bump spends belongs to the client, and it is the asset the agency is being paid to build.
Where the Tool Stops Mattering
Warmup protects delivery for a campaign whose offer and list the client largely controls. An agency can build perfect infrastructure and still produce nothing from a weak offer, which then becomes a retention conversation.
The second limit is the qualification definition. Meetings booked against criteria nobody wrote down get disputed at invoice time, so agree what counts in writing before launch and never accept budget, timing or authority as billing conditions.
Final Thoughts
Many clients, protecting the margin: TrulyInbox, where mailbox count does not drive the bill. Clear per-mailbox arithmetic and a custom-pricing path above 100 mailboxes: Mailreach. One client with a damaged domain: InboxAlly. Clients standardised on lemlist: Lemwarm. Warmbox is roughly one client per subscription.
Related Reading
- Best Lemlist Alternatives in 2026
- Best Mailreach Alternatives in 2026
- Best Warmbox Alternatives in 2026
- Best TrulyInbox Alternatives in 2026
- Best InboxAlly Alternatives in 2026
- Email sending tools for agencies
If you would rather have this run for you, RevenueFlow books qualified meetings on a pay-per-meeting basis and publishes client results.
Pricing and features are taken from the vendors' own pages. Verify current terms with the vendor before relying on them.
Frequently asked questions.
Frequently asked questions- How should an agency price warmup across clients?
- Start from the unit rather than the headline. Every client needs its own domains and inboxes, so the mailbox total grows as clients multiplied by inboxes each, and a per-mailbox charge multiplies straight through it. A tool that prices warmup volume across unlimited accounts absorbs the roster instead, which is usually where the margin is.
- When should an agency start warming a new client's domains?
- At onboarding, before the campaign is built. Warmup lead time belongs in the onboarding schedule and in what the client is told, because an agency that promises campaigns in week one spends weeks three and four explaining poor placement. The honest version is that warming starts on day one and sending starts later.
- How long does email warmup actually take?
- Longer than any signup flow suggests. The software connects a mailbox in minutes, and the sending history it then builds is measured in weeks, which is why the domains should be bought and warming before the list and the copy are ready. No plan tier shortens that, because what you are buying is time rather than throughput.
- How much warmup volume do I need?
- TrulyInbox publishes the sizing rule on its pricing page: warmup runs on a 2:1 ratio, two warmup emails for every one cold email, every day and ongoing. Multiply your intended daily cold sends per mailbox by two, add up across inboxes, and buy the plan covering that daily total rather than an average.
About the author.
B2B cold email experts helping companies generate qualified leads through done-for-you outreach campaigns.
RevenueFlow Team
Explore more.
Ready to scale your outreach?
We build GTM engines that book real meetings. See the receipts.
Related articles.
Pipedrive vs GoHighLevel: Per Seat Against Per Agency, and What Each Is Actually Built For
One charges per user, the other a flat fee with unlimited users. That difference names each product's buyer, and it predicts nearly everything else about the comparison.
Anymail Finder Pricing: The Credit Ladder and What a Verified Email Costs
The published credit ladder, why the page shows two different currencies at once, and why paying per verified result changes the arithmetic on a hard list.
CallRail Pricing: Four Plans, and Three Versions of the Page That Sells Them
CallRail publishes four plan prices and then meters numbers, minutes and API calls on top of them. Its pricing page also ships three versions of itself.
Proxycurl Alternatives After the Shutdown: What Actually Replaces It
Proxycurl shut down in July 2025 under a LinkedIn settlement. The replacement options, what each publishes, and the risk that moved rather than vanished.
Tavus Pricing: Two Ladders, and Which One You Are Actually Buying
Tavus publishes a consumer ladder and a developer ladder on one page. Which one you are quoted, what the access fee really buys, and where the page contradicts itself.
Visualping Pricing: Which Limit Binds First, Checks or Pages
The full published plan table, and the arithmetic that decides your tier: every plan carries two limits, and only one of them binds for any given use case.