Best Email Warmup Tools for Startups (2026)
The five email warmup tools worth comparing for Startups in 2026, with prices read off each vendor's own pricing page and an honest read on fit.
Email warmup for startups should start the day the first sending domain is bought, and TrulyInbox's pricing page lists a free forever plan for 1 account. Paid tools split by unit: Lemwarm and Mailreach charge per mailbox, Warmbox caps plans at 6 inboxes, and TrulyInbox charges for daily warmup volume.
Key takeaways
- TrulyInbox publishes a free forever plan for 1 account at 10 warmup emails a day, then Starter at $22/mo annually or $29/mo monthly for 200 a day across unlimited accounts.
- Mailreach's FAQ says the initial warmup phase should last 14 days minimum with no campaigns, and Warmbox's FAQ puts first results at 15 to 30 days.
- At 10 inboxes on monthly billing Lemwarm Essential costs $290 a month and TrulyInbox Growth $99, while Warmbox's largest named plan stops at 6 inboxes.
- TrulyInbox's published sizing rule is a 2:1 ratio: two warmup emails for every cold email, every day and ongoing.
Reviewed and updated September 21, 2026
Email warmup for startups is the step that decides when a new company can actually start sending, and it is the one nobody budgets time for. The software takes ten minutes. The weeks of sending history it then has to build are the real cost, and no plan tier shortens them. This guide compares five tools on the prices their own pricing pages publish: TrulyInbox, Mailreach, InboxAlly, Lemwarm and Warmbox.
Email Warmup for Startups: The Short Answer
Start warming the first sending domain the day you buy it, on a free plan if you can: TrulyInbox's pricing page lists a free forever plan for 1 account at 10 warmup emails a day. When you need paid capacity, choose by the next twelve months. Per-mailbox pricing gets dearer as inboxes multiply; TrulyInbox's volume pricing does not.
For an outbound-driven SaaS startup that adds inboxes as it hires, that makes a volume-priced tool the default and a per-mailbox tool the choice for a founder who will stay on one or two mailboxes. The same test answers the enterprise version of the question: compare the unit each tool bills on against your inbox count and daily volume, then compare prices.
What Startups Need From an Email Warmup Tool
Lead time is the requirement that matters most and gets planned least. A founder who buys domains on Monday and expects to campaign on Friday has misunderstood the category: Mailreach's FAQ says the initial warmup phase should last 14 days minimum with no campaigns sent, and Warmbox's FAQ says first results usually take 15 to 30 days of uninterrupted warming. Buy the domains and start warming before the list, the copy or the sending platform are ready, so the slowest step runs in parallel with everything else.
Cost matters, and at startup scale the pricing unit barely does, because one or two inboxes cost roughly the same however they are billed. What matters is the step after that. A startup that adds inboxes as it hires will meet the difference between per-mailbox pricing and volume pricing within a year.
Free options are genuinely useful here. This list has one free forever plan and two published trials, TrulyInbox's 7 days on its paid plans and InboxAlly's 10 days with no credit card. A free plan that warms a single inbox is enough to start the clock on the first domain while the rest of the motion is still being built.
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, and each figure is attributed to that page. Two pages localise their currency: Mailreach rendered in euros for this comparison and Lemwarm in pounds, and the text says so where it matters. No lab test sits behind this, so the guide makes no claim about which tool produces the best inbox placement.
Top 5 Email Warmup Tools for Startups
1. TrulyInbox
Warmup platform priced on the emails it sends rather than the accounts you connect. TrulyInbox's pricing page headline reads "Pay for emails sent. Not accounts connected."
| Plan (TrulyInbox pricing page) | Billed annually | Paid monthly | Warmup emails/day | Best suited for | Reply rate |
|---|---|---|---|---|---|
| Free | Free forever, 1 account | Free | 10 | 1 account | |
| Starter | $22/mo, $264/year | $29/mo | 200 | 3 email inboxes | up to 25% |
| Growth | $84/mo, $1,008/year | $99/mo | 1,000 | 15 email inboxes | up to 45% |
| Scale | $169/mo, $2,028/year | $199/mo | 3,000 | 50 email inboxes | up to 60% |
| Scale Plus | $407/mo, $4,884/year | $479/mo | 5,000 | 100 email inboxes | 65% |
Two things there matter more than the prices. It states Unlimited Accounts on every paid plan, the opposite of how most of this list bills. And it publishes the sizing rule: warmup runs on a 2:1 ratio, two warmup emails per cold email, every day and ongoing. Its Starter example shows the arithmetic: 3 mailboxes, 67 warmup emails per mailbox a day, and about 33 cold emails per mailbox. Paid plans carry a 7-day free trial and a 14-day money-back guarantee.
The natural startup entry point: the free forever plan starts the clock at no cost, and Starter at $22/mo annually or $29/mo monthly adds 200 warmup emails a day across unlimited accounts as inboxes multiply.
2. Mailreach
Warmup and deliverability platform that bundles spam testing with the warmer.
| Mailreach pricing page | Published figure |
|---|---|
| Warmup rate, monthly | €25 / mailbox Per Month |
| Warmup rate, annual | €20 / mailbox, 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 |
The page is a calculator rather than a plan ladder, and it rendered in euros for this comparison. Its unrendered HTML also carries a dollar figure beside running totals that do not match it, so the dollar price a US visitor sees was not confirmed here; check it before budgeting. Above 100 mailboxes the page quotes custom pricing. Simple and predictable for a founder-led setup, it becomes the more expensive shape at the point the startup adds inboxes faster than volume.
3. InboxAlly
Deliverability platform that trains inbox placement using its own seed inboxes rather than a peer network.
| 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 | Thousands | Unlimited |
The page prices everything billed monthly and offers a free trial of 10 days with no credit card required. At $149 / month it is disproportionate to an early-stage budget, and the trial is worth knowing about mainly as a diagnostic if a domain has already gone wrong.
4. Lemwarm
Warmup tool from lemlist that builds sender reputation across what its pricing page calls a warm-up network of 20k+ healthy domains, with a technical setup check and deliverability reports.
| 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. The page also offers Quarterly billing at Save 10% against Yearly at Save 20%, and it renders in local currency, which from this comparison's address meant the same numbers in pounds. It states that every lemlist plan includes lemwarm, so check what you already own before buying separately: for a startup already on lemlist it is the cheapest option of all.
5. Warmbox
Warmup tool with fixed plans, growth, flat or random warm-up, a fully custom warm-up option, spam score monitoring and a reporting dashboard.
| 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 and covers 6 inboxes, so a seventh is a Contact Us conversation. For a single inbox it is the cheapest named paid plan on any of these pages, at $15 /month on yearly billing.
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 many 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. The chart above shows the shape on monthly billing: at 10 inboxes Lemwarm Essential is $290 a month, TrulyInbox Growth is $99, and Warmbox has no named plan.
Comparison Table
| Tool | Entry price | Free option |
|---|---|---|
| TrulyInbox | Free, then $29 a month, or $22 annually | Free forever for 1 account; 7-day trial on paid plans |
| Mailreach | €25 per mailbox a month, €20 annually | No free plan on the page |
| InboxAlly | $149 a month | 10-day trial, no credit card |
| Lemwarm | $29 per email a month, $24 yearly | Included with every lemlist plan |
| Warmbox | $19 a month, $15 yearly | No free plan on the cards |
Recommendation by Budget
Starting at nothing. TrulyInbox's free forever plan for 1 account at 10 warmup emails a day is the only ongoing free plan on this list.
The cheapest paid tiers. Warmbox Solo is $15 /month yearly and $19 /month monthly for 1 inbox warm-up; Lemwarm Essential is $24 yearly and $29 monthly per email; TrulyInbox Starter is $22/mo annually and $29/mo monthly for 200 warmup emails a day across unlimited accounts.
The middle, where the unit bites. Mailreach and Lemwarm charge per mailbox, so ten mailboxes cost roughly ten times one, while TrulyInbox Growth is $84/mo annually and $99/mo monthly for 1,000 warmup emails a day whatever the inbox count.
The upper published tiers. InboxAlly starts at $149 / month for 100 seed emails a day, with $645 and $1,190 named above it, and TrulyInbox Scale is $169/mo annually and $199/mo monthly.
How to Choose
Start it before you are ready. Warmup is the long pole, measured in weeks on two of these vendors' own pages.
Does the next twelve months add inboxes or add volume? That answer picks between per-mailbox and volume pricing, and it is the choice a startup most often gets wrong by optimising for today.
Are you already paying for it? Check whether your sending platform bundles warmup; Lemwarm is included with every lemlist plan.
Does the daily volume match the plan? Apply the published 2:1 ratio: two warmup emails for every cold one. Size the plan to that number, not to the top of the ladder.
Warming Without Wasting the Month
Buy sending domains before you buy anything else, keep them well away from the domain that carries product, billing and investor mail, authenticate them with SPF, DKIM and DMARC, and start warming immediately. This is the single highest-leverage thing a founder can do in the whole setup, because it is the only step that cannot be compressed.
Ramp gradually rather than opening at full speed. New inboxes with no history get classified quickly and the damage is slow to undo.
Send one message per campaign. A startup's list is small enough that burning it with repeated sends is a real cost, and a single sharp email to fifty well-chosen people beats a sequence to five hundred badly chosen ones at this stage.
Where the Tool Stops Mattering
Warmup is necessary and nowhere near sufficient. It does nothing for the list or the offer, and a perfectly warmed domain delivering a weak message to the wrong people produces a well-delivered nothing.
The second limit is patience. Outbound takes weeks to produce signal and warmup takes weeks before that, and switching tools in the middle resets the domain history along with the learning.
Final Thoughts
Start today at no cost: the TrulyInbox free forever plan. Cheapest named paid plan for one inbox: Warmbox Solo. Already paying for lemlist: lemwarm is included. Inbox count about to grow: TrulyInbox Starter or Growth. Founder-led with one or two mailboxes and spam testing wanted: Mailreach, priced in euros for this comparison.
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 startups
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- What is the best email warmup tool for a startup?
- It depends on how your inbox count will grow. TrulyInbox's pricing page lists a free forever plan for 1 account and volume pricing with unlimited accounts, which suits a startup adding inboxes as it hires. Warmbox Solo at $15 a month on yearly billing is the cheapest named paid plan for one inbox, and Lemwarm is included with every lemlist plan.
- How long does email warmup take for a new domain?
- Longer than most founders plan for. Mailreach's pricing FAQ says the initial warmup phase should last 14 days minimum with no campaigns sent, and Warmbox's FAQ says first results usually take 15 to 30 days of uninterrupted warming. Buy the sending domains and start warming before the list, the copy and the sending platform are ready.
- Is there a free email warmup tool?
- Yes. TrulyInbox's pricing page lists a free forever plan for 1 account at 10 warmup emails a day, with no credit card. InboxAlly offers a 10-day free trial with no credit card, and TrulyInbox's paid plans carry a 7-day trial. Lemwarm is free for anyone already paying for a lemlist plan, according to its pricing page.
- How do I compare email warmup tools for a growing team?
- Compare the billing unit before the price. Lemwarm charges per email address and Mailreach per mailbox, Warmbox sells plans capped at 1, 3 or 6 inboxes, and TrulyInbox charges for warmup emails sent per day across unlimited accounts. Work out your inbox count and daily sending volume for the next twelve months, then price each tool against both.
About the author.
B2B cold email experts helping companies generate qualified leads through done-for-you outreach campaigns.
RevenueFlow Team
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