Best Email Warmup Tools
Three pricing models exist and they diverge fast. Per-inbox (Warmup Inbox, from $15/inbox), per-volume with unlimited inboxes (TrulyInbox, from $29), and bundled into a sending platform (Instantly, $47 including unlimited warmup).
The crossover: at one inbox, per-inbox is cheapest. At ten, the same job costs $47 bundled, $99 per-volume, or $490 per-inbox on Pro. Count your mailboxes before you compare features.
We do not sell a warmup product, which makes this easier to write honestly. We do run warmup on customer sending mailboxes as part of our outreach agent, so the practical notes here come from operating it rather than from reviewing it.
Every price below is a published rate read from the vendor's own pricing page on 24 August 2026. Rates move, so check before you buy. Where a vendor does not publish a rate, we say so rather than estimating one.
The three pricing models
Almost every comparison of these tools comes down to feature checklists, and the features are broadly the same: a pool of cooperating mailboxes, a rising send schedule, spam rescue, and a dashboard. What actually separates them is how they charge.
| Tool | Model | Published entry price | What that buys |
|---|---|---|---|
| Warmup Inbox | Per inbox | $15 / inbox / month (Basic) | 75 warmup messages a day, per inbox. |
| Warmup Inbox (Pro) | Per inbox | $49 / inbox / month | 250 a day, custom templates, language warmup. |
| TrulyInbox | Per volume | $29 / month (Starter) | 200 warmup emails a day, unlimited accounts. |
| TrulyInbox (Growth) | Per volume | $99 / month | 1,000 a day, unlimited accounts. |
| Instantly | Bundled | $47 / month (Growth) | Unlimited warmup, inside the sending platform. |
| ZeroBounce ONE | Bundled | $99 / month | Warmup plus validation, placement tests, DMARC monitoring. |
| Mailwarm | Not published | Not published | Publishes $0.02 per interaction overage and a custom plan only. |
Warmup Inbox and TrulyInbox both publish 7-day free trials without a card. TrulyInbox additionally publishes a free-forever tier: one account, 10 warmup emails a day. That is slow, but it is genuinely free and enough to warm a single mailbox if you are patient.
Where the models cross over
This is the part worth doing arithmetic on, because the answer changes completely between one mailbox and ten.
| Plan | 1 inbox | 3 inboxes | 10 inboxes | 25 inboxes |
|---|---|---|---|---|
| Warmup Inbox Basic | $15 | $45 | $150 | $375 |
| Warmup Inbox Pro | $49 | $147 | $490 | $1,225 |
| TrulyInbox Starter | $29 | $29 | $29 | $29 |
| TrulyInbox Growth | $99 | $99 | $99 | $99 |
| Instantly Growth | $47 | $47 | $47 | $47 |
Monthly figures at list price, ignoring annual discounts. Two caveats on reading the flat rows: TrulyInbox Starter's 200 emails a day has to stretch across every inbox you connect, so at ten mailboxes that is 20 a day each, which is a thin warmup. And Instantly's number only applies if you are sending through Instantly anyway.
The practical reading is that per-inbox pricing is the right answer for one or two mailboxes and the wrong answer for a team. At three inboxes Warmup Inbox Basic is still cheaper than TrulyInbox Growth. By ten it is $150 against $99 for considerably more daily volume, and Pro has reached $490 for a job the bundled option does for $47.
The question that decides it
Before comparing anything, ask whether your sending platform already includes warmup. Instantly bundles unlimited warmup at $47 a month on its entry plan, and ZeroBounce bundles it into a $99 suite alongside validation and placement testing. If you are already paying one of those, a standalone subscription is duplicated spend.
The honest cases for a standalone tool are narrow but real: you send through a platform that does not include warmup, you want warmup running on mailboxes before you have chosen a sending platform, or you deliberately want the warmup vendor to be different from the sending vendor so the reputation signal is not entirely in one company's hands.
What to check that the feature lists will not tell you
Does it report inbox versus spam placement, or only a health score? A health score is a vendor's opinion. Placement is a measurement. Ours is the number we actually watch: across 18 warmed mailboxes, 417 of 434 warmup emails landed in the inbox and 8 went to spam, and the useful detail was that 15 of the 18 saw no spam at all. Concentrated spam means one broken mailbox; spread-out spam means a domain or list problem. A tool that only shows a score cannot tell you which you have.
How long is the ramp, and can you set it? Real warmup runs weeks. Our own mailboxes run 21 days on a slow schedule or 40 to 42 days on a normal one. A tool advertising a warmed inbox in days is not building the signal it claims to.
Does the daily volume divide across inboxes or apply per inbox? This is the detail that makes per-volume plans look cheaper than they are at scale.
Have you checked SPF and DMARC first? No tool on this page can help a domain that fails authentication. Of 19 sending domains we hold health data for, six had an invalid SPF or DMARC record. Buying warmup for one of those is spending weeks fixing the wrong problem. The detail is in email warmup.
Which to pick
| Your situation | The honest answer |
|---|---|
| One mailbox, no budget | TrulyInbox's free tier. Slow at 10 a day, but free and real. |
| One or two mailboxes | Warmup Inbox Basic at $15 each. Per-inbox wins at this size. |
| You already use Instantly to send | Use the warmup it includes. Do not buy a second tool. |
| Five or more mailboxes, sending elsewhere | A per-volume plan. Check the daily allowance divides acceptably. |
| You want validation and placement testing too | ZeroBounce ONE bundles them; compare against buying separately. |
| Your SPF or DMARC is invalid | None of them yet. Fix the records first. |
Frequently asked questions
How much do email warmup tools cost?
From $15 per inbox per month (Warmup Inbox Basic), $29 a month for 200 emails a day across unlimited inboxes (TrulyInbox Starter), or bundled free into a $47 sending platform (Instantly Growth). The model matters more than the number.
Is there a free email warmup tool?
TrulyInbox publishes a free-forever tier: one account, 10 warmup emails a day. Warmup Inbox and TrulyInbox both offer 7-day trials without a card.
Do you need a standalone tool if your platform includes one?
Usually not. Instantly includes unlimited warmup at $47. Paying separately on top is duplicated spend unless you are warming mailboxes that will send elsewhere.
What should you check before buying?
Your real inbox count against the pricing model, whether it reports placement rather than just a score, whether daily volume divides across inboxes, and whether your SPF and DMARC are valid in the first place.
How long should warmup run before sending?
Three to six weeks. Our mailboxes run 21 days slow or 40 to 42 days normal. Start it before you need the mailbox, not when you are ready to send.
Method
Prices were read from each vendor's published pricing page on 24 August 2026 and are list monthly rates unless stated; annual billing discounts exist at several vendors and are not included. Mailwarm does not publish plan pricing, so it appears without a rate rather than with an estimated one. Placement, schedule and authentication figures are from our own production warmup records and cover small samples (18 mailboxes for placement, 19 for schedule and authentication), described in full in email warmup. We do not sell a warmup product and have no affiliate relationship with any vendor listed.