This week one of the bigger cold email infrastructure providers added warmup as a paid add-on at $3 per mailbox per month. That's roughly the same cost as the mailbox itself. If you're running 500 inboxes, that's an extra $1,500 a month for something your sequencer most likely already does.
The structural problem matters more than the price tag. Warmup doesn't belong on an infrastructure provider's invoice in the first place. The right home for it is the sequencer that already controls your sending patterns. When infrastructure providers sell warmup as a SKU on top of an existing sequencer subscription, customers either pay twice for the same job or run two warmup systems against the same inbox.
Warmup Is Core to Cold Email
For every cold email you send from an inbox, the operating rule is two warmup emails from the same inbox. Run this 2:1 ratio for the lifetime of the inbox. Most operators cut warmup back after the initial 2-3 week ramp and then watch their reputation drift down over the following weeks.
That means warmup volume runs at roughly 2x your cold volume every day, every week, for as long as the inbox is alive. We've covered the mechanics in our email warmup guide, but the operational reality is that warmup is an always-on background process. The positive engagement signals from warmup are what bury the negative signals from cold outreach. Stop running it, and your reputation drifts inside a few weeks no matter how clean your copy is.
That part nobody serious about cold email disagrees on. The argument worth having is about which layer of your stack should run warmup, because that decision shows up in your invoice and your inbox health.
The Math at 100, 500, and 1,000 Mailboxes
$3 per mailbox per month sounds small in isolation. The math at scale tells a different story.
| Inboxes | Add-on warmup cost / month | Add-on warmup cost / year |
|---|---|---|
| 100 | $300 | $3,600 |
| 500 | $1,500 | $18,000 |
| 1,000 | $3,000 | $36,000 |
To give you an idea of how that compares: at 1,000 inboxes, most providers charge somewhere in the $3,000 to $5,000 range for the mailboxes themselves. Add warmup at $3 per mailbox and you're paying close to a second base subscription. In most cases, your sequencer is already running warmup at no extra cost. The $3 buys you a duplicate of something you already have.
Where Warmup Actually Belongs
Warmup needs three things to do its job:
- Visibility into your daily sending pattern. Warmup volume should scale with your cold volume. The system running warmup needs to know how many cold emails you sent today, what your reply pattern looks like, and how the inbox is being used.
- Realistic engagement. Warmup emails should look like real human exchanges (mostly read, sometimes replied to, occasionally starred), not boilerplate ping-pong between bots.
- Tight feedback loop with the inbox. When deliverability slips, warmup should adjust. That requires the warmup engine to see the same engagement signals your campaigns produce.
Your sequencer has all three. Smartlead, Instantly, EmailBison, and PlusVibe AI all run warmup in the same panel where your campaigns run. They see your send volume, your reply rate, and your inbox engagement in real time. That's the data warmup actually needs.
The infrastructure provider sees DNS, IPs, and inbox health. That's their job and it's a real one. Asking them to also run warmup is like asking your domain registrar to write your email copy. They don't have the data for it. Even if the warmup volume runs cleanly, it's running blind to the campaigns it's supposed to be supporting.
What Warmup-Ready Infrastructure Actually Looks Like
The infrastructure layer's job is the foundation that makes warmup work in the first place. The pieces that have to be right:
Authenticated DNS from day one. SPF, DKIM, and DMARC configured correctly at the domain level before the first send goes out. Our DNS settings guide walks through what each record does and where most setups get it wrong. If your provider treats DNS configuration as a separate add-on too, the product is mailbox provisioning. Don't pay infrastructure prices for it.
IP rotation built into the platform. Sending all of your warmup and cold mail from a single IP concentrates risk on that IP. When it goes bad, every inbox connected to it suffers at once. Real cold email infrastructure rotates IPs at the platform level so one bad campaign doesn't take down the whole batch.
Realistic per-inbox sending limits. On Microsoft setups we run 5-10 cold emails per day per inbox plus warmup. On Google, 15-25 cold per day plus warmup. Anything higher invites trouble. Providers that quietly let you push past those numbers are letting you torch your own infrastructure on the way to next month's invoice.
Domain rotation across batches. Run Batch A for 3 weeks while Batch B rests at minimum warmup volume. Swap. If the platform doesn't have batches as a first-class concept, it's treating cold infrastructure like marketing infrastructure, and the two are different jobs.
Reputation monitoring as a default. Built in by default and running daily, without a separate dashboard you're supposed to remember to check. The whole point of monitoring is catching reputation drift before it costs you a domain.
These are the pieces the infrastructure layer should provide. Warmup runs on top of them, in the sequencer, where the data lives.
What the Warmup Add-On Actually Costs You
Two things happen when you buy warmup as an infrastructure add-on while your sequencer is already running warmup:
- You pay for the same job twice. $3 per mailbox per month for the infrastructure add-on, plus whatever you're already paying for your sequencer (where warmup is a built-in feature). At 500 mailboxes, that's $18,000 a year of duplicate spend.
- You can end up running two warmup systems against the same inbox. Both schedule outbound warmup mail from the same address. Neither knows the other exists. The result is over-volume that looks bot-like to inbox providers, which is the opposite of what warmup is supposed to do.
The second one is the real risk. The first is just a line item that shouldn't be there.
The exception worth naming: if you're sending without a sequencer (manual SMTP, custom-built tool with no warmup module), then yes, you need warmup from somewhere. Almost no one runs cold outbound that way at scale anymore. If you're operating at the volume where the $3 per mailbox math adds up, you're using a sequencer.
How We Think About Warmup at ScaledMail
ScaledMail focuses on the infrastructure layer: domains, DNS, IP management, inbox provisioning, and reputation monitoring. Warmup runs in your sequencer where it has the data to do the job right. That keeps our per-mailbox price lean and keeps customers from paying twice for the same outcome.
If we ever launch a managed warmup layer, it'll be because the major sequencers leave a gap that's worth filling, and the price will be set against what those sequencers already include. We're not interested in selling something customers don't need or charging them again for something they're already getting.
The other reason this matters: when warmup lives at the infrastructure layer and your sequencer also runs warmup, neither system can do its job well. The sequencer doesn't know the infrastructure is also pumping warmup volume. The infrastructure doesn't know the sequencer is doing the same. Keeping warmup in one place keeps the math clean and the inbox healthy. We run 217,000+ inboxes across our customer base, and the setups that survive past 12 months are the ones where each layer of the stack is doing one job, well.
Our guide to cold email infrastructure providers breaks down who does what across the major options if you want to see how the lines get drawn.
The Rest of the Cold Email Stack
Once warmup is solved at the right layer (your sequencer), the work that actually moves results lives in your messaging and targeting. We've written deeper guides on cold email deliverability and the cold email infrastructure setup we recommend for teams sending 5,000-50,000 emails a month. None of that work pays off if the foundation underneath is wrong.
Warmup is the part of the stack that's invisible when it works. If it's missing or under-running, you don't notice for two or three weeks, and by then you've already burned half your domains. That's why this matters operationally. The pricing question is downstream of a bigger one. Which system in your stack is actually best positioned to run warmup? In 2026, the answer is your sequencer.
If a provider sells warmup as an add-on, ask: what does my sequencer already do? In most cases, the honest answer is "the same thing, included."
Frequently Asked Questions
Does ScaledMail include warmup?
ScaledMail doesn't run warmup directly today. We focus on the infrastructure layer (domains, DNS, IP rotation, inbox provisioning, monitoring) and let your sequencer handle warmup, since that's where the engagement data and send patterns live. If we add a managed warmup layer in the future, the price will reflect what your sequencer already covers, not what an infrastructure markup looks like.
Which sequencers include warmup at no extra cost?
Most of the major cold email sequencers bundle warmup as a built-in feature: Smartlead, Instantly, EmailBison, and PlusVibe AI all include it. The implementations vary in quality, but the principle is the same. Warmup runs in the same panel as your campaigns, with full visibility into your sending patterns.
Can I just turn off warmup once my domains are aged?
No. The 2:1 warmup ratio is maintained for the lifetime of the inbox, not only during the initial 2-3 week ramp. Warmup engagement signals are what bury the negative signals from cold outreach. Once you stop running warmup, your reputation drifts inside a few weeks regardless of how aged the domain is.
If my sequencer already runs warmup, do I still need an infrastructure provider?
Yes. Warmup runs on top of infrastructure that has to be set up correctly first. DNS authentication, IP rotation, realistic sending limits, and reputation monitoring are jobs that have to be done at the infrastructure layer regardless of which sequencer you use. Warmup at the sequencer layer can't fix bad DNS or burn-prone IPs.
What happens if I run warmup in my sequencer and also buy the infrastructure add-on?
You're either paying twice for the same outcome or running two warmup systems against the same inbox. The second case is the risky one. Both systems scheduling warmup mail from the same address can produce over-volume patterns that look bot-like to inbox providers. The clean answer is to pick one place where warmup runs and turn it off everywhere else. For most teams in 2026, the sequencer is the right pick.
