Step-by-Step Email List Warming Playbook

Follow these Warm-Up strategies for Gmail & Outlook in 2025 Warm-up rules aren’t universal anymore. Each provider—Google, Outlook, or SMTP—has its own quirks, and ignoring them could ruin your inbox placement before you even start. Let me break it down step-by-step: 1️⃣ Follow Provider-Specific Warm-Up Settings Warm-up is different for Google, Outlook, and SMTP. You can’t treat them the same. Google: Start at 5 emails/day per mailbox. Slowly increase to 20-25 emails/day over the first 14 days. Outlook: Start lower, at 3-5 emails/day per mailbox, and only reach 20/day max by day 31. (Otherwise, stick with your providers’ recommended warm up) 💡 Insight: Keep reply rates high—at least 80%-100% reply rate—and make sure every email is starred, marked as important, and pulled out of spam. 2️⃣ Respect the Domain Aging Timeline Google-friendly domains: Wait at least 14 days before sending outbound campaigns. Outlook-friendly domains: Wait 30-60 days (ideally closer to 60) to avoid instant flags. 3️⃣ Scale Outbound Slowly After Warm-Up Once warm-up is complete, don’t immediately send at full volume. For both Google and Outlook, start outbound campaigns at: → 5 emails/mailbox/day. Increase by 5 emails/week until you hit a max of 20-30/day per mailbox. For Outlook specifically, use personalization tools like Octave or Twain to randomize your emails. Without personalization, Outlook will flag your campaigns within days. Takeaway: Slow down, follow the rules, and think long-term. Rushing into high-volume campaigns without a proper warm-up will only burn your domains, IPs, and reputation. 💬 Have more deliverability questions? Drop them below—I’ll answer in my next post!

Warming up your domain is the most overlooked step in cold email. Here's the 14-Day Rule that's kept our campaigns out of spam folders: Week 1: Send 5-10 emails per day to friends, colleagues, or team members. Have them reply and engage with your emails. Week 2: Gradually increase to 20-30 emails per day. Mix personal emails with light business outreach. After 14 days: Your domain has established sending history and reputation. You essentially want your warmup process to mimic natural email behavior. It shows email providers you're a legitimate sender (instead of a spammer). Obviously, properly warmed domains consistently achieve higher inbox placement rates. The domains we rushed into cold outreach without warmup landed in spam within days. While the ones we warmed up properly maintained strong deliverability for months. This applies whether you're using Google Workspace, Outlook, or any other email provider.

We recently had a client that bought a business out of bankruptcy, inheriting over 12 million emails that needed to be warmed up. As my friend once put it, mass sending emails to cold prospects is a lot like sneaking cocaine across the Mexican border – high risk and tricky to manage. Here are the strategies we used to warm up this massive email list: 1. Start Small and Engaged: We began by targeting the most engaged contacts first. This phased approach ensured high open rates and avoided deliverability issues, gradually expanding the list to maintain quality. 2. Use Engagement Triggers: Simple tricks like asking recipients to reply to your email can significantly improve your inbox placement. A strategy we use involves plain text emails with calls to action like, “Reply YES if you want to stay updated.” This not only boosts engagement but also signals email providers that your content is valuable. 3. List Cleaning: Tools like NeverBounce can clean your list by removing invalid addresses, reducing the chance of hard bounces. In our case, we ran our lists through NeverBounce to filter out invalid emails before importing them into our email service provider. 4. Autoresponders for Relationship Building: Setting up autoresponders that immediately engage new contacts helped establish relationships early. A welcome email encouraging replies set a positive tone and improved deliverability. 5. Be Strategic with Content: For warming strategies, plain text emails often perform better than HTML-heavy designs. They feel more personal and are less likely to trigger spam filters. By applying these techniques, we successfully warmed up the list and turned this dead asset into a money-generating machine. Hope this helps anyone dealing with similar challenges.

I burned through $15K perfecting cold email copy. Here's what I learned when I focused on deliverability instead. While I was obsessing over subject lines and CTAs, most of my emails were landing in spam folders. I had killer copy that nobody ever saw. But here's what happened when I fixed the infrastructure piece first… I went from ignored emails to 800,000+ monthly sends at ColdIQ. If your cold emails aren't working, deliverability beats copy every single time. WHY DELIVERABILITY IS EVERYTHING: 1. Perfect copy means nothing in spam. You can have killer targeting, perfect messaging, incredible offers... but if your email lands in spam? Game over. 2. It compounds everything else. Once your domain reputation is down, even your transactional emails start getting flagged and won't get delivered anymore. So how do you make your email in the primary? 1. Protect your main domain. Never send cold emails from your primary domain. We use 70+ secondary domains to keep our brand safe and our main inbox clean. 2. Distribute volume across multiple mailboxes. Set up 140+ mailboxes across those domains. Keep it under 50 sends per day per domain. High volume too early = instant red flag. 3. Get your technical foundation bulletproof. Set up SPF, DKIM, and DMARC authentication. Without proper technical set-up, you're flagged as suspicious by default. 4. Warm up. Send nothing for 2 weeks. Use premium warm-up tools to build trust gradually with ESPs. Ramp slowly to avoid triggering their spam filters. Patience here pays dividends later. 5. Natural variation. Use Spintax or tools like Twain to introduce variations in your messaging. Even small variations help you avoid the repetition triggers that scream "mass email blast" to spam filters. Remember, list quality plus message still matter most. Even with perfect infrastructure, if your list is off and your message is weak, you'll still land in spam. Deliverability gets you to the inbox, but the relevance keeps you there. Monitor everything rigorously. Use tools to track your sender reputation across all ESPs. We check deliverability rates daily (it's that critical). Infrastructure gets you to the inbox, but your targeting plus messaging determines what happens next. I've put together a 7-day GTM crash course that includes our exact setup, authentication templates, and the monitoring systems we use to protect the campaigns of our 70 clients. Reply with "SETUP" if you want access before your next campaign goes live.

After reviewing data from 1,000s of inboxes at RevGrowth, these 8 practices have made the biggest impact for consistent 99% email deliverability:   Most teams skip at least one of these, then wonder why their cold emails land in spam.   Here's what we do:   1. Use Secondary Domains - Never send from your main domain > We buy secondary domains through Porkbun for cheap, easy management   2. Track Replies Only - Open and click tracking hurt deliverability > I keep reply tracking on and turn everything else off. Clean signal, less risk   3. Send Fewer Emails Per Mailbox - I stick to 30 emails/day per mailbox, max > Spread your volume across several domains. Fewer red flags, more consistency   4. Warm Up Slowly - Ramp up sending volume over time. > Start low, increase gradually. This builds trust with inbox providers.   5. Double-Verify Your Lists - Bad data kills sender reputation > We use LeadMagic, Icypeas, and Prospeo.io for email search, then verify with LeadMagic. Clean lists = low bounce rates   6. Use Modern Sending Platforms - Old-school SEPs drag down deliverability > I recommend EmailBison or Smartlead   7. Automate CRM Syncing - Manual updates cause errors and missed follow-ups. > OutboundSync handles real-time syncing with HubSpot or Salesforce. Less manual work, more accuracy.   8. Stick to Plain Text - Links and images lower inbox rates. > I write text-only emails. They look more human and get better placement.   Our team applies these 8 steps in every workflow ourselves & all client accounts.   What’s been your biggest deliverability challenge lately?