Chris Dalton

Best Email Warmup Tools

January 18, 2026

I set up email warmup backwards the first time. Connected the wrong inbox, let it run for four days before Derek pointed out nothing was actually warming. Once I fixed it, deliverability went from around 34% inbox placement to closer to 71% over a few weeks. You need one of the best email warmup tools before you send anything at volume. I've tested the main ones. Here's what I found.

What Email Warmup Actually Does

Email warmup tools gradually increase your sending volume while maintaining positive engagement signals. They send emails from your account to a network of real inboxes, those inboxes open and reply to your emails, and your domain builds a reputation with email providers as a legitimate sender.

Without warmup, if you suddenly start sending 200 cold emails a day from a fresh domain, Gmail and Outlook will flag you as spam immediately. Warmup solves this by making your domain look like it's been sending and receiving legitimate email for months.

Look, if you're sending cold emails without warmup recent years, you're basically announcing "I'm a spammer" to Gmail. Not ideal.

The process works by connecting your email account to a network of thousands of other users running the same warmup software. Your account sends emails to these addresses, they open your messages, mark them as important, reply to them, and pull them out of spam folders if they land there. This creates positive engagement signals that teach email service providers your domain is legitimate.

Think of it like building credit history. A new domain has no reputation-it's neutral. Email providers don't know if you're a legitimate business or a spammer. Warmup builds that history through consistent, positive interactions over weeks.

How Email Service Providers Judge Your Reputation

Before diving into specific tools, you need to understand what actually affects your sender reputation. Email providers like Gmail, Outlook, and Yahoo use complex algorithms to determine whether your emails deserve the inbox or spam folder.

Tory just told me I have "great bone structure" and then asked if he could borrow forty dollars. I don't know what those two things have to do with each other.

They track your engagement rates-how many people open your emails, reply to them, mark them as important, or move them to folders. High engagement signals legitimacy. They also monitor complaint rates-how many recipients mark your emails as spam or unsubscribe immediately. Even a 0.1% spam complaint rate can damage your reputation.

Sending patterns matter enormously. If you send 5 emails on Monday, 200 on Tuesday, and 10 on Wednesday, that erratic behavior looks suspicious. Warmup tools solve this by ramping up volume gradually and maintaining consistent daily sending.

Your technical setup plays a role too. Email providers check your SPF, DKIM, and DMARC records to verify you're authorized to send from your domain. If these authentication protocols aren't properly configured, even warmed accounts will struggle with deliverability.

Smartlead

I set this up thinking the warmup and the sending were two separate things I had to connect. Spent probably 45 minutes looking for an integration setting that didn't exist because they're already the same thing. Derek watched me do this and didn't say anything until I figured it out, which was annoying.

Once I stopped fighting it, the warmup ran in the background without me touching it. I had three accounts going at once and the system spread the volume across all of them automatically. I didn't configure that. It just did it. My open rates on the first real campaign out of warmup came in around 31%, which was higher than I expected given how fast I'd moved through setup.

The warmup network is real inboxes doing real things – opening, replying, pulling stuff out of spam. What I noticed after a few weeks is that the interactions started feeling familiar in a weird way. Like the same few patterns kept showing up. I don't know if that means anything. Nobody told me it would be a problem, so I kept going.

Pricing confused me. I signed up for the middle plan because I thought the basic one had a warmup limit. It doesn't. The limits are on leads, not warmup accounts. I probably could have started cheaper and been fine for the first two months.

If you're already doing cold outreach at volume, the consolidation is genuinely useful. All replies land in one place regardless of which account sent the original email. I stopped checking three inboxes. That alone saved me real time every morning.

If you're only sending a small volume daily, this is more tool than you need right now.

Try Smartlead

Instantly

I set up the warmup on the wrong accounts first. I thought you had to pick which ones to include, so I spent probably 45 minutes adding addresses one by one before Derek pointed out it just runs on everything automatically. There's no list to manage. I don't know why I assumed there was a list.

Once I got out of my own way, it actually ran fine. The slow ramp handled itself – starts low, builds up over days, doesn't ask you anything. I didn't touch it after that. My spam placement was sitting around 38% on one domain when I started. After about three weeks it came down to just under 9%. I wasn't expecting it to do much, honestly.

The ESP matching thing is real. I didn't fully understand it when I turned it on, but the idea is it pairs your domain with warmup accounts on the same provider. I was on Google Workspace and I think that's why it moved faster than the other domain I tested, which was on a cheaper host. That one took longer.

You can set open rates, reply rates, how much it varies day to day. I changed a few things and then changed them back. The defaults were probably fine. I also thought the randomization setting was broken because the numbers looked weird, but it was just doing what it said. I was reading it wrong.

Pricing is somewhere around $37 or $97 a month depending on the plan – I'm on whatever the middle one is. Warmup is in there, not separate. If you're already sending through this platform, there's no reason to go find another warmup tool.

Try Instantly

Lemlist

I had Lemwarm running for about three weeks before I realized I'd set the daily sending limit way too high. I thought more warmup emails meant faster results. It doesn't work like that. I dropped it down and things actually started moving in the right direction. Deliverability improved noticeably around day 18 or 19, which lines up with what the tool says to expect.

The network is real people, not bots. Your emails go out, get opened, get replied to. The replies look like actual conversation threads, not the obvious filler text I'd seen with other tools I tried before this one. That part impressed me. I was expecting it to be more obviously mechanical.

There's a feature that groups your warmup activity with senders in similar industries. I spent probably 45 minutes trying to configure it manually before I figured out it mostly handles itself. I don't think I needed to touch it at all. Jamie had told me to adjust the cluster settings but I'm still not sure that did anything.

Open rates on my primary domain went from around 31% to 47% over the warmup period. That's the number I actually tracked. Could be other factors. Probably wasn't.

Pricing confused me a little. There are three tiers and warmup is included in all of them, but I had to read the plan comparison twice before I believed it wasn't a separate add-on. It's not. It's just included.

The catch is it only works if you're already using the cold email platform it's attached to. If you're not, this one isn't for you.

Try Lemlist

Mailreach (Standalone Warmup)

I connected three inboxes on the first day and somehow ran the warmup at double the intended volume for about a week before I noticed. I thought the "aggressive" setting meant faster results. It does not mean that. I scaled it back and things normalized, but I probably could have just left it on the default and been fine from the start.

It only does warmup. No sequences, no sending, no lead lists. You plug in your email accounts and it runs. Works with Gmail, Outlook, SMTP, most of what you're probably already using. That part was genuinely easy. I had all three accounts connected in under twenty minutes.

The reputation dashboard is a separate paid add-on, which I did not realize until I was already looking for it. I spent a while clicking around thinking I had missed it somewhere. I hadn't. You pay extra for it. Once I added it, it was actually the most useful part. You can see your score by provider and watch it move week over week. My Gmail reputation went from a 61 to an 84 over about five weeks, which was enough to stop landing in promotions on most sends.

The inbox placement testing is also separate from the main warmup. You send to a seed list and get a report on where things are landing. I used it before I started a campaign for Derek and it caught a problem with our Outlook setup I would have missed entirely.

Pricing is per inbox per month. Simple enough, but it adds up faster than you'd expect if you're managing accounts for multiple people. Tory asked me about it for her team and I honestly had to go back and recalculate because I'd gotten confused about what was included.

If you only have a few inboxes and you're already using something else for sending, this is probably the cleanest option available. It does one thing and mostly stays out of your way.

Warmbox (Standalone Warmup)

I connected this one backwards at first. I thought I was supposed to pick the aggressive warmup setting because our domain was newer and I figured faster would be better. Derek told me later that was probably the wrong call. I switched to the default gradual setting after about a week and a half, and that's when things actually started moving. Spam placement dropped from around 34% down to 11% by the time I was done, which I did not expect given how rocky the start was.

The setup itself is straightforward enough. You connect your email, pick a warmup recipe, and it runs. There are four options. I used the wrong one first, as mentioned. The custom option I didn't touch because I wasn't sure what I was customizing toward. Most of the time I just watched the dashboard and waited.

The network it sends through is large. I don't know the exact number but the emails it generated looked different every time, which surprised me. I assumed warmup emails were all the same boilerplate. These weren't. I checked a few that came through and they read like actual messages, different topics, different lengths. I don't know how it does that but it held up.

There's a setting where you can limit sending to business hours in your timezone. I did not find this immediately. I found it after noticing activity happening at 2am and thinking something was broken. It wasn't broken, I just hadn't configured it. Once I set that, it looked a lot more normal.

Pricing is where I got confused. I think I'm on the middle tier. I'm warming up three accounts and I'm not sure if I'm paying for five slots or just the three I'm using. I meant to check that. The per-account cost is lower than the other standalone tool we looked at, which is why Tory approved it.

The one thing I couldn't get around is that there's almost no review history anywhere I looked. I searched before we bought it and found almost nothing recent. That made me nervous. It still makes me a little nervous.

Warmup Inbox

I connected my first inbox in maybe eight minutes. I know because I was timing it, trying to win a bet with Derek about whether it would take longer than setting up our CRM integration. I won, technically, though I had spent the previous twenty minutes reading the wrong setup guide on their site before finding the right one.

The thing I kept messing up was the warmup schedule. I had it running at full send volume immediately instead of ramping up gradually. That's apparently an option you set yourself, not something it does automatically. I assumed it was automatic. It is not automatic. My open rates on actual campaigns that week were weird enough that Stephanie noticed and asked me what I changed. I hadn't connected those two things yet.

Once I figured that out, the reputation score tracker became the part I actually checked every morning. It shows you where you sit against other users on the platform, and you can set a threshold so it alerts you when things start sliding. My score dropped slightly around day nine and I caught it before it became a real problem. Bounce rate on that inbox went from around 14% down to about 5% over three weeks, which was roughly what I was hoping for.

The warmup emails themselves look a little robotic. I pulled a few from the sent folder just to read them and they felt like something generated by a form. I don't know if that matters or if it hurt anything, but I noticed it.

Pricing confused me at first. I thought the base plan covered everything and upgraded halfway through my first month before realizing the features I wanted were on the higher tier. I don't fully understand the per-inbox structure even now. I have four inboxes running and I'm honestly not sure what I'm paying total. Linda handles the billing side and she mentioned it adds up faster than it looks on the pricing page.

Support responded fast when I submitted a question, faster than I expected. That part worked exactly how it was supposed to, which was a relief given how badly I had set everything else up at the start.

TrulyInbox

I connected maybe eleven or twelve inboxes before I realized I'd been going through the setup process one at a time like an idiot. There's a way to batch it. I don't know how long that would have taken me to figure out on my own. Derek mentioned it offhand during a standup and I felt like an idiot. Anyway, the unlimited inbox thing is real – I kept waiting for a cap to appear somewhere and it never did.

The pricing confused me at first. I thought the free plan was a trial that would expire. It didn't. I'm still not entirely sure what the difference is between what I tested for free and what I'm paying for now. Something about reply rate controls and daily ramp-up volume. I do have those now and I use them, so I assume that's the difference.

The warmup behavior felt legitimate. It's not blasting – it staggers sends and uses what I can only describe as a slow build. My deliverability score went from 61 to 84 over about three weeks, which was faster than I expected. Open rates on the first real send after warmup came in around 31%, which is not something I was getting before.

There's a deliverability dashboard. I checked it more than I needed to, mostly because I wasn't sure if the warmup was actually doing anything. It was. I just didn't trust it yet.

Setup for Gmail was fast. SMTP configuration for one of the other accounts took me longer than it should have because I entered the port number wrong. I didn't figure that out for two days. The emails just weren't sending and I kept looking in the wrong place.

For anyone managing inboxes across multiple clients, the consolidation is the actual selling point. Tory had been tracking warmup status in a spreadsheet. That spreadsheet is gone now. That alone probably justified the monthly cost, whatever it actually is.

Which One to Pick

I ended up connecting the warmup on the wrong account first. Took me a bit to figure out why nothing was improving – I had the right tool pointed at the wrong inbox. Once I sorted that, open rates on warmed accounts were sitting around 34% versus the cold ones that were still stuck in the low teens.

If you're already inside Smartlead, Instantly, or Lemlist, just use what's already there. I didn't realize warmup was already running in the background until Derek mentioned it. Saved me from paying for something separate I didn't need.

If you're on a different sending tool, the standalone options gave me more flexibility. Mailreach made sense for a smaller account count. Once we got past five or six inboxes, Warmbox started making more financial sense – though I'm honestly not sure I read the pricing page correctly the first time.

For a lot of accounts at once, TrulyInbox was the one I stopped second-guessing. Flat fee, unlimited inboxes. Linda handles our agency accounts and she pointed me toward it. Tory pays per inbox somewhere else and keeps complaining about the bill.

Understanding Warmup Networks

All warmup tools rely on networks of real email accounts exchanging messages. The size and quality of these networks directly impacts warmup effectiveness.

Someone left a note on my desk that just says "stay golden." I don't know who wrote it or what it means but I'm keeping it.

Network size matters, but quality matters more. A network of 50,000 established, high-reputation inboxes beats 100,000 throwaway Gmail accounts created specifically for warmup. Email providers can detect patterns when warmup activity comes primarily from new, low-activity accounts.

The best warmup networks include diverse email providers. Your warmup should include interactions with Gmail, Outlook, Yahoo, and custom domain addresses. If you only warm up against Gmail accounts but then send campaigns primarily to Outlook recipients, you're building reputation with the wrong provider.

Geographic diversity helps too. Warmup networks that span multiple countries and languages create more natural-looking activity patterns. This becomes especially important if you're targeting international markets.

Some tools use peer-to-peer networks where everyone using the service contributes their inbox to the pool. Others maintain dedicated warmup accounts. Peer-to-peer networks tend to have higher-quality accounts since they're real business addresses, but they also mean your warmup partners are other cold emailers who might have their own reputation issues.

How Long Warmup Takes

Most tools claim 2-4 weeks for noticeable deliverability improvements. In reality, it depends on your domain age, previous sending history, and target volume.

Brand new domain: 4-6 weeks minimum before sending serious volume. Start slow, let the warmup run continuously. New domains have zero reputation, so providers treat them with maximum suspicion. Rushing this process almost guarantees spam folder placement.

Every vendor says "2-3 weeks" but I've watched new domains take 6+ weeks to consistently hit primary inbox. Plan accordingly and don't launch your big campaign on week two because you're impatient.

Established domain with good history: 1-2 weeks to prepare for increased sending volume. If your domain has been sending normal business email for months and you want to start cold outreach, warmup builds on existing positive reputation. You're not starting from zero, so improvement comes faster.

Domain with spam issues: 6-8 weeks to rebuild reputation, assuming you've fixed whatever caused the spam flags in the first place. If your domain got flagged because of purchased lists, spammy content, or authentication issues, warmup alone won't fix it. You need to address the root cause first, then spend extended time rebuilding trust.

Dormant domain: 3-4 weeks to reactivate. If you have a domain that was previously active but hasn't sent email in months, providers have essentially forgotten about you. You need to re-establish reputation, but it's faster than starting fresh.

Don't rush this. Warmup isn't a checkbox-it's ongoing maintenance. Keep it running even after you start sending campaigns. Many people make the mistake of running warmup for a few weeks, starting their campaigns, then stopping warmup entirely. This causes reputation to decay over time.

Warmup Volume and Campaign Volume

Your warmup volume and actual campaign sending volume need to align. This is one of the most common mistakes people make with email warmup.

If your warmup is set to 30 emails per day and you suddenly start sending 200 cold emails daily, you'll tank your deliverability immediately. Email providers notice the sudden spike and flag you as suspicious. Your actual sending volume should stay within or slightly below your warmup targets.

Build a buffer. If you plan to send 100 cold emails per day, warm up to 120-150 daily. This gives you headroom for occasional higher-volume days without triggering red flags.

Account for total volume across all your sending. If you're warming up one account but rotating sends across five accounts, each individual account only needs warmup for its share of the volume. However, domain reputation matters too, so some warmup activity should occur on all accounts even if they're not all sending campaigns simultaneously.

When scaling up, increase gradually. Don't jump from 50 to 200 emails per day overnight. Increase by 10-20% per week while monitoring your deliverability metrics. If you see declining open rates or increasing bounces, you're scaling too fast.

Common Warmup Mistakes

The first mistake I made was turning off warmup the second my actual campaign started. Made sense to me at the time – warmup's done, move on. But my open rates dropped noticeably within about ten days and I couldn't figure out why until Derek looked at my settings and said "you just turned off the thing that was keeping your reputation stable." You leave it running. That part I had backwards for longer than I'd like to admit.

The volume mismatch thing got me too. I had warmup sitting at around 40 emails per day and then sent a 300-email cold campaign on a Tuesday because I thought those were separate systems. They're not really separate. My deliverability took about three weeks to recover. Bounce rate went from around 6% back up to 19% that week. I didn't connect the cause until after the damage was done.

There's also a version of this mistake where you warm up properly but then route your actual sends through a different setup. I did this. Warmed up through one path, sent through another. The reputation I built didn't transfer. Tory explained it to me like I was a little slow, which was fair. The warmup is specific to how the mail actually travels, not just the account name.

I also copied my settings from one account to a second domain we'd just registered and assumed it would work the same way. It didn't. New domains need slower ramp-ups. The older domain was fine. The new one got flagged within the first week and I spent two days troubleshooting something that would've been fine if I'd just used more conservative settings from the start.

The mistake I see people skip over is not watching the metrics during warmup. There's a reputation score in the dashboard and I ignored it for almost three weeks because I assumed things were progressing. They weren't, really. Something in my technical setup was off. Once I actually looked at the numbers and fixed the underlying issue, scores started moving within a few days.

Launching before warmup finishes is the one I hear about most. I did not do this, but only because I ran out of things to set up and had no choice but to wait. Sometimes the best email warmup tools work best when you're forced to be patient.

Do You Really Need Warmup?

Honestly, I didn't think I needed warmup at first. I was sending maybe 15 or 20 emails a day from a domain I'd had for a while. Skipped the whole setup. It was fine. Derek does the same thing and he's never touched a warmup tool. If you're at that volume on an established domain, you're probably okay.

Where it actually matters is when you're pushing 50+ cold emails a day or you're starting on a fresh domain. I set up a new domain for a campaign and just started sending before the warmup finished. Open rates were around 11% for the first week. Once I let the warmup run the full cycle, I got to around 27% on the same sequence to a similar list. That gap was annoying to figure out but it made the case pretty clearly.

The thing I got wrong was thinking warmup was mostly for new domains. It's also for volume. I didn't connect those two situations until I'd already burned about a week of sending on the underperforming domain. Tory pointed out I had it set up right, I just started the campaign before the warmup period finished. There was a status indicator I wasn't checking.

If you're sending transactional stuff to people who already opted in, I wouldn't stress about it. Your real engagement handles that. And if you had deliverability problems before, warmup helps, but whatever you were doing wrong before will just undo it. Fix that first or you're just running the same loop.

Technical Setup That Matters

Warmup tools can't fix broken technical setup. Before investing in warmup services, verify your domain authentication is properly configured.

SPF (Sender Policy Framework) tells email providers which servers are authorized to send email from your domain. Without a proper SPF record, providers can't verify you're legitimate. Check your SPF record covers all your sending sources-your email platform, warmup tool, and any other services sending from your domain.

DKIM (DomainKeys Identified Mail) adds a digital signature to your emails that proves they haven't been tampered with. This cryptographic verification helps providers trust your messages. Most email platforms handle DKIM automatically, but verify it's working before starting warmup.

DMARC (Domain-based Message Authentication, Reporting, and Conformance) tells providers what to do with emails that fail SPF or DKIM checks. Start with a monitoring-only policy to collect data, then move to quarantine or reject policies once you've verified everything is working correctly.

Custom domains beat generic email providers for cold outreach. Sending cold emails from @gmail.com looks less professional and gives you less control over reputation. Purchase a domain specifically for cold outreach so issues don't affect your main business domain.

Separate sending domains from your main business domain. If your company website is acme.com, send cold emails from acmesales.com or similar. This isolation protects your primary domain reputation if cold outreach encounters problems.

Monitoring Deliverability

Warmup tools provide reputation scores, but you should also monitor actual campaign performance to verify deliverability.

I really hope everyone on the team is doing okay. Sometimes I worry people aren't telling me things.

Track open rates consistently. If open rates suddenly drop 30-40%, you likely have a deliverability problem. Your emails are hitting spam folders instead of inboxes. This happens before you'll see changes in bounce rates, so it's an early warning signal.

Monitor spam complaint rates. Most email platforms report how many recipients marked your emails as spam. Keep this under 0.1%. Even 0.3-0.5% is enough to damage reputation significantly. If complaints spike, pause campaigns immediately and investigate.

Watch bounce rates carefully. Hard bounces (invalid addresses) and soft bounces (full inboxes, temporary issues) both affect reputation. Keep total bounce rate under 3-5%. Higher bounce rates signal you're sending to low-quality lists.

Use seed testing to verify inbox placement. Send test emails to your own accounts across different providers before launching campaigns. If your tests hit spam folders, your real campaign emails will too.

Google Postmaster Tools provides detailed data on your sending reputation with Gmail. You can see your domain reputation, IP reputation, spam rate, and feedback loop data. This free tool gives insight into how Gmail specifically views your sending.

Microsoft SNDS (Smart Network Data Services) offers similar data for Outlook and Hotmail. Register your sending IPs to get reputation data and spam trap hits. This helps you identify problems before they become severe.

Cost Analysis

I did not think about pricing the right way when I started. I signed up for standalone warmup on a per-inbox plan and it was fine for the first two accounts. Then Derek asked me to add four more and I did the math wrong somehow. I thought it would be like twenty dollars more. It was closer to a hundred and ten. I don't know how I missed that.

The bundled platforms where warmup is already built in made more sense once I actually looked at them. You're paying more up front but you're not stacking separate bills. I wish someone had told me that before I set everything up the other way.

The flat-fee option was the one that finally worked for our situation. We were managing eight domains at that point and the cost stopped moving, which felt strange at first. I kept waiting for an overage charge. There wasn't one.

The real number that got my attention was this: I burned a domain early on because warmup wasn't configured right. Replacing it, redoing the DNS records, waiting for it to settle – I lost about three and a half weeks before that inbox was usable again. My open rates on the new domain were at four percent when I started over. They were at twenty-three percent after warmup finished. That gap is what warmup actually costs you if you skip it.

Scaling Multiple Accounts

Serious cold emailers use multiple email accounts to spread volume and protect individual domain reputations. Warmup strategy changes when managing many accounts.

Tory's eating beef jerky directly from a bag in his car because his wife took the house. He gave me a thumbs up through the windshield and smiled. I waved back.

Start with 3-5 accounts minimum. This lets you rotate sending to keep individual account volume reasonable. If you need to send 150 emails daily, three accounts sending 50 each works better than one account blasting 150.

Warm all accounts simultaneously, even if you're not using them all yet. When an account sits idle after warmup, reputation decays. It's easier to maintain warmup continuously than stop and restart.

Stagger warmup start dates slightly. Don't connect ten brand new domains to warmup on the same day-it looks suspicious if all your domains suddenly spring to life simultaneously. Space new account creation by a few days or weeks.

Use consistent naming conventions. If your accounts are [email protected], [email protected], [email protected] with similar content, providers may link them together. Some reputation damage could spread across accounts. Vary the names, domains, and content enough to maintain separation.

Monitor aggregate reputation across all accounts. If 3 of your 5 accounts see declining deliverability simultaneously, you likely have a systemic issue with your list quality, content, or sending practices rather than individual account problems.

When to Pause or Stop Warmup

I actually didn't know you were supposed to keep warmup running the whole time. I turned it off on one account because I thought we were done with it. Reputation dropped from a 7.4 to a 5.1 in about two weeks. Derek pointed out I had it backwards.

If the score dips below a 7, the right move is to pause your real campaigns, not the warmup. Let the warmup run on its own for a bit. That's what pulled us back up. Took longer than I expected, maybe three weeks, but it worked.

There was one account where the provider flagged it for suspicious activity mid-warmup. I kept the tool connected for four days before I realized that was making it worse. Disconnect immediately if that happens. Then call support before you do anything else.

If you're not sending for a while, dial the volume back but don't kill it completely. I went to almost nothing on one account and regretted it.

The one thing I'd actually push back on is cutting warmup to save money. It's not expensive. Losing a good sending domain costs more than whatever you're saving.

Alternative: Manual Warmup

You can warm up email accounts manually without paid tools, but it's tedious and time-consuming.

Start by sending 3-5 emails daily to real people who will open and reply. Increase by 2-3 emails daily every few days. Reach your target volume after 4-6 weeks. Every email should get opened and ideally replied to, so reach out to colleagues, friends, or business contacts who will engage.

Vary your content significantly. Don't send the same message repeatedly-providers detect patterns. Write unique emails with different subject lines, content length, and formatting.

Include normal business correspondence in your warmup. If you're sending invoices, project updates, or customer communications from the account, that counts as positive engagement.

Pull emails out of spam folders manually. Have your warmup partners check their spam folders and move your messages to inbox if they landed there. This trains the algorithms that your emails belong in the inbox.

The problem with manual warmup is sustainability. You need to do this every single day for weeks, then maintain ongoing activity even while running campaigns. Most people can't maintain the discipline, which is why automated tools exist.

Manual warmup makes sense if you're only warming one account, you're on an extremely tight budget, and you have the time and discipline to execute consistently. For everyone else, paying $15-30/month for automated warmup is worth it.

Red Flags That Warmup Isn't Working

I didn't notice things were going sideways until my open rates had already been sliding for about two weeks. I kept thinking the tool just needed more time. It didn't. The warmup was running, the numbers looked active, but nothing was actually improving. That's the part that got me – it looked like it was working.

Derek told me later that if you're three weeks in and your reputation score hasn't moved at all, something is already broken. Could be a setup issue, could be the tool itself sending weird-looking traffic. Mine was flat for 23 days before I stopped and actually looked at what was happening.

The one that really stung was finding the warmup emails themselves in my own spam folder. I didn't check that for the first week and a half. I just assumed it was fine. It was not fine. I disconnected that account the same afternoon.

There was also a domain I spent probably six weeks trying to salvage. I don't know what the previous owner did with it but nothing touched the reputation. Tory said just buy a new one. She was right. I should have done it on week two.

If your opens are dropping while warmup is still running, or you're getting sending limits from your provider mid-warmup, don't keep going. Stop, figure out what's actually broken, then restart. Continuing didn't help me once.

The Bottom Line

I set up warmup on three accounts before I realized I had the send volume way higher than what I was actually sending. Nobody told me that was a problem. I just noticed my open rates were weird - like 9% on stuff that should've been higher - and Jamie mentioned offhand that the warmup-to-send ratio was probably off. I fixed it. Opened at 31% the next week.

For most people, just use whatever comes bundled with your platform. Smartlead, Instantly, and Lemlist all include it. I didn't need a separate tool until we were running more accounts than I could keep track of in a spreadsheet.

The standalone stuff makes more sense once you're managing five or more accounts. I honestly don't fully understand how the pricing tiers work on most of them. I just picked one that didn't charge per account and stopped thinking about it.

Your list and your copy are doing the real work. Warmup just stops the emails from disappearing before anyone sees them. Looking for more? Check out our guides on best cold email software and best cold email tools.