What if I already sent a large blast and my reputation is damaged?

Stop sending immediately. Wait 5-7 days. Then restart the warmup process from step 1, beginning with your most engaged 30-day segment at low volume. Recovery takes longer than getting it right the first time — typically 60-90 days of disciplined sending to rebuild trust.

Do I need to warm up if I'm switching from Mailchimp to Klaviyo?

Yes, if you're using a new sending domain or subdomain. The warmup is about the domain, not the platform. If you're keeping the exact same sending domain and authentication records, the warmup is shorter (1-2 weeks) since inbox providers already have history on that domain.

Can I speed up the warmup process?

Not safely. Rushing warmup is the number one reason brands end up in spam. The 2-4 week timeline exists because inbox providers need time to build a reputation profile for your domain. Trying to compress this into a week almost always results in deliverability problems.

Should I warm up separately for Gmail, Yahoo, and Outlook?

No — a general warmup strategy covers all providers. But Gmail is the strictest, so if your Gmail open rates are healthy, you're typically fine everywhere else. Google Postmaster Tools is the most important monitoring tool during warmup.

What engagement rates should I see during warmup?

During warmup, target 40%+ open rates and click rates above 3%. You're sending to your most engaged subscribers, so rates should be high. If open rates drop below 25% at any point, you're moving too fast. Slow down, reduce volume, and focus on your most engaged segment.

Email Deliverability Guide

Stop. Before you send that first campaign — you need to warm up your domain.

If you just set up Klaviyo, migrated from another platform, or switched to a new sending domain and you're about to blast your entire list — don't. You'll land in spam, tank your reputation before you even get started, and spend the next 3 months trying to recover.

Inbox providers like Gmail, Yahoo, and Outlook don't trust new sending domains. They have zero history on you. So when a brand-new domain suddenly sends 20,000 emails, their algorithms flag it as suspicious. The result: your first campaign — the one you spent hours crafting — goes straight to junk folders.

Domain warmup is the process of gradually increasing your send volume so inbox providers learn to trust you. It takes 2-4 weeks. It's boring. And it's absolutely mandatory. Here's the exact schedule we use for every Klaviyo migration.

2-4 weeks

Warmup Period Required

95%+

Inbox Placement After Proper Warmup

80+

Domains We've Warmed

<0.1%

Target Spam Complaint Rate

How to fix this — step by step

Authenticate your domain before anything else

In Klaviyo, go to Settings → Domains → Add Sending Domain. Add a dedicated subdomain like send.yourstore.com. Klaviyo provides SPF, DKIM, and DMARC DNS records — add all three to your DNS provider. Wait for verification (usually 24-48 hours). Without authentication, inbox providers won't even consider trusting your domain. This is step zero. Everything else depends on it.

Start with your most engaged subscribers only (days 1-3)

Create a segment of your most engaged subscribers — people who've opened or clicked within the last 30 days. Send your first campaign to just 200-500 of these people. Why engaged subscribers first? Because they're most likely to open, click, and reply. Those positive signals tell inbox providers "this sender is legitimate." If your first sends get low engagement, the algorithm penalizes you before you've even started.

Double your volume every 2-3 days (days 4-14)

Day 1-3: 200-500 subscribers. Days 4-5: 1,000. Days 6-7: 2,000. Days 8-9: 4,000. Days 10-12: 8,000. Days 13-14: 15,000. Each increase should go to progressively less-engaged segments — 30-day engaged, then 60-day, then 90-day. Monitor your open rates and spam complaints after every send. If open rates drop below 25% or spam complaints rise above 0.1%, pause for 2 days and reduce volume on the next send.

Monitor Google Postmaster Tools daily

Register your domain at postmaster.tools.google.com. It shows your domain reputation (High, Medium, Low, Bad), spam rate, and authentication status. During warmup, check this daily. You want "High" reputation and spam rate below 0.1%. If reputation drops to "Medium," slow down. If it hits "Low," pause all sending for 3-5 days and only resume with your most engaged 30-day segment. This tool is your early warning system.

Turn on your automated flows during week 2

Your welcome series, abandoned cart, and browse abandonment flows should go live in week 2 of warmup. Flow emails have naturally high engagement rates (they're triggered by real behavior), which actually helps your warmup. The positive signals from flow emails support your campaign sends. Just make sure your flows are sending from the same authenticated domain as your campaigns.

Reach full volume by week 3-4

By the end of week 3, you should be able to send to your full engaged list (90-day engaged segment) without deliverability issues. Don't extend to unengaged subscribers — they should be in a sunset flow or suppressed. "Full volume" means your engaged audience, not your total list. If your warmup went smoothly and open rates are above 30%, you're clear for regular campaign cadence.

Want us to handle this?

If you follow this schedule precisely, you'll have a warmed domain with strong sender reputation in 3-4 weeks. We've done this for over 80 domain migrations and it works every time.

But warmup is just the start. Maintaining deliverability — ongoing list hygiene, engagement monitoring, authentication updates, inbox placement testing — requires continuous attention. We handle all of this for our Klaviyo clients so they never have to worry about emails landing in spam. If you need help with a domain warmup or migration, the audit is free.

Get a Free Deliverability AuditWe'll walk through your setup live.

Questions our best clients asked first

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