How infrastructure affects email credibility

In 2023, I thought deliverability was a copy problem. In 2024, I learned it was a tech stack problem. By 2025, it’s clear → infrastructure is the moat. We manage over 2.5M cold emails/month. Across industries, price points, and geos. The patterns are painfully clear: → Weak IP reputation = you’re invisible. → Poor server setup = you’re throttled. → Sloppy domain rules = you’re blacklisted in 30 days. → Aggressive sending = you burn TAM before you build a pipeline. The best copy in the world can’t save you from bad infrastructure. But the right infrastructure can make average copy work 10x longer. Here’s the 2025 Deliverability Standard we run at NextGen Sales Systems before a single campaign goes live: #1 IP Reputation – Dedicated, warmed, disciplined. #2 Server Setup – Matched to mailbox provider. #3 Domain Rules – Segmented, aged, never primary. #4 Sending Patterns – Slow, steady, controlled growth. If you skip this, your campaigns will plateau in weeks. If you nail it, you can run the same system for months with consistent inbox placement. Cold email is no longer about finding clever lines, it’s about building a system the email service provider algorithms trust. That’s how you win in 2025.

Google is deleting your cold emails before they even hit inbox. This happened to us recently!! We had: - Clean list. - Warmed domain. - SPF, DKIM, DMARC — all ✅ - Great copy. But stil… Zero replies. We thought something was off. It was: our infrastructure. Gmail doesn’t just scan your words. It scans how you send, from where, and what patterns you follow. If any of it looks off, your emails are erased before they reach anyone. What fixed it for us: 1. We set-up our own Infra: We set up our own SMTP server Postfix on a VPS. Hooked it to a dedicated IP. No shared infra. No third-party fingerprints. → Clean sender identity. Now Gmail treats us as a standalone sender not a bulk app user. 2. We fully configured DNS (beyond the basics) Most people set SPF, DKIM, and DMARC and think they’re done. Wrong. You also need: - PTR records (reverse DNS) - FCrDNS (forward-confirmed reverse DNS) These are what Gmail uses to verify that your IP = your domain. 3. We slowed everything down Started sending 5–10 plain-text emails/day. Just real messages, written manually. Replies boosted sender reputation. Then we scaled up slowly over 45 days. Volume only grew when reply rates held steady. 4. We re-learned how to write No fancy formatting. No AI-sounding “quick questions.” No calendar links. Instead we used: - all small caps email - made mistakes on emails Gmail flags anything that looks templated or mass-produced. 5. We implemented greylisting + rate-limiting Most people don’t know what this is. We configured our server to: Accept retry attempts from legit mail servers The bursts that look like spam behavior Gmail tracks this. It’s their way of filtering real senders from spam bots. If your infra can’t retry or slows down under load that’s a good thing. 6. We started live monitoring everything We now use internal dashboards to monitor: - Spam feedback loops (Spamcop, AOL, etc.) - IP reputation health - Open/reply/soft bounce signals - Domain temperature Auto-rotation of sending IPs One red flag… The system pauses, reroutes, and resets warm-up if needed. Most founders optimize copy. Smart founders fix infrastructure. Google’s AI doesn’t care how clever your hook is. It cares how trustworthy your server looks from the outside. I’m still learning and implementing things day by day —— Send this to your SDR

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.

I ran 3 cold email campaigns simultaneously, each using a different provider.   My goal was to find out the best email infrastructure for maximum deliverability.   Campaign 1: Gmail accounts Campaign 2: Outlook accounts Campaign 3: Maildoso accounts   After sending 1,000 emails through each:   Gmail results: → 27% open rate → 1.3% reply rate → 62% of emails in spam   Outlook results: → 31% open rate → 2.8% reply rate → 48% of emails in spam   Maildoso results: → 64% open rate → 11.9% reply rate → 2% of emails in spam   The setup experience:   Gmail setup: → 6+ hours configuring 25 mailboxes → $157/month + domain costs → Manual SPF/DKIM setup for each domain   Outlook setup: → 5+ hours for 25 mailboxes → $175/month + domain costs → Constant authentication issues   Maildoso setup: → 5 minutes for 25 mailboxes → $75/month (domains included) → All DNS records configured automatically   After 1 month (reputation):   Gmail: Declining scores, more spam flags Outlook: Poor deliverability, frequent issues Maildoso: High scores, strong performance   I finally realized that achieving high deliverability is only possible using a single, purpose-built SMTP provider like Maildoso.   Why I use Maildoso infrastructure: ✅ Maildoso's in-house SMTP infrastructure (not resold server space) ✅ IP rotation that prevents mailboxes from getting flagged ✅ Daily inbox placement tests that show exactly where emails land ✅ One-click domain redirects that improve recipient trust   For sales teams sending cold emails at scale, the math is simple: Same effort, 5-6x better results with Maildoso.   Try Maildoso, and you’ll no longer worry about cold email deliverability.

The best cold email is the one that’s seen. You can spend hours perfecting your message. You can send it to the perfect lead at the perfect time. You can have the best subject line, CTA, and segmentation. 👉  But if your email lands in spam… none of it matters. This is the quiet killer of cold outreach. Not your copy. Not your timing. Your domain health. Deliverability isn’t exciting. But it’s the difference between scaling campaigns and being invisible. And the worst part? Many teams don’t even realize they’re being flagged. They think they have a copy problem. Or a product-market fit issue. When in reality, they just haven’t taken care of their infrastructure. Here’s how to avoid that mistake: 1️⃣ Warm up inboxes before sending anything Never start cold. If you go from zero to 100 emails per day, you’ll trigger spam filters immediately. → Start with low volume. → Gradually increase daily sends over 2–4 weeks. → Use a tool that mimics natural sending patterns. 2️⃣ Verify every email address before hitting send Bad data = high bounce rates. High bounce rates = domain reputation damage. → Anything over 5% bounce rate is a red flag to ESPs. → Clean your list with tools like Bouncer inside Woodpecker.co → Avoid catch-alls and outdated leads from bought lists. 3️⃣ Authenticate your domain properly SPF. DKIM. DMARC. These aren’t optional - they’re your technical foundation. → SPF = who’s allowed to send on your behalf → DKIM = proves your emails are legit → DMARC = tells inboxes how to handle failures If you skip any of these, your emails are more likely to hit spam - even if everything else is right. 4️⃣ Monitor performance like a hawk Deliverability isn’t “set it and forget it.” It’s something you manage actively. → Rotate inboxes if volume increases → Create new domains proactively - not reactively → Track open, reply, bounce, and complaint rates daily Track deliverability with Deliverability Monitor in Woodpecker to spot any upcoming issues. Copy doesn’t win if nobody sees it. The best cold email is the one that makes it to the inbox. You don’t rise to the level of your copy. You fall to the level of your domain health. So - how are you protecting your cold email infrastructure?

We've identified a real estate platform enforcing a broken email authentication model. The platform requires a dedicated DMARC record for a subdomain before allowing mail through its SparkPost infrastructure. The platform routes all outbound email through a subdomain. Even if SPF and DKIM are correctly implemented, messages will still fail authentication unless the platform's "recommended" #DMARC record is deployed. The trick is that the record cannot be altered - any tag modification breaks authentication. It also includes an RUA tag pointing to a non-existent email address with no MX records assigned (tied to a subdomain), preventing customers from receiving DMARC reports. According to #RFC7489, the root domain's DMARC policy already covers all subdomains, making the platform's requirement illegitimate. This approach not only violates established security practices but also prevents clients from monitoring their own deliverability data, suggesting the platform may be intentionally obscuring its sending infrastructure and practices. #EmailSecurity #EmailDeliverability #DNS #DomainAuthentication

Real email success comes from understanding both sides of the equation: Email placement & Email performance 1. Email Placement = Technical Trust This is where your email lands: >> Primary inbox >> Promotions tab >> Spam folder >> Blocked completely Placement is driven by: → SPF / DKIM / DMARC → Bounce rates & spam complaints → IP / domain reputation → Other records + infrastructure If this part’s broken, it doesn’t matter how good your email is. Nobody sees it. 2. Email Performance = Human Signals This is what happens after your email is delivered. Mailbox providers are watching. And these behaviors send strong positive signals: >> Opens, clicks >> Replies >> Forwards or starring >> Dwell time And these behaviors send Negative Signals: Deleting without reading Archiving without interaction Long streaks of no engagement The key to remember is that *performance feeds placement*. Consistent positive engagement? → Better sender reputation → Better inbox placement → Compounding returns You can’t just be a great copywriter. You can’t just be a great technician. The best email marketers are both. They think like engineers and storytellers. They optimize placement and performance. That’s how you consistently land in the inbox — and stay there.

VP Sales: "We need 10,000 decision-maker emails for our ABM campaign." Me: "Show me what you're using now." "Apollo, ZoomInfo, some Linked In screping." No wonder their bounce rate was 27%. We audited an Adobe partner's email database. 8,000 "verified" contacts from premium data vendors. Ran them through our validation stack: • Syntax check (RFC 5322 compliance) • DNS/MX record verification   • SMTP handshake without sending • 100% Catch-all verification • Role-based email filtering (info@, sales@) • Honeypot/spam trap cross-reference • Disposable domain detection • Corporate email pattern matching Real deliverable emails? 3,712. But we went deeper with our 43 B2B APIs: • Email age scoring (how long at company) • Job change detection (LI API + news monitoring) • Email engagement history (opens/clicks from 3rd party data) • Domain reputation scoring • IT infrastructure mapping (O365 vs Google Workspace) • Email alias detection (same person, multiple addresses) All this through EmailAddress .ai, in a few minutes. The ACTUAL list? 2,847 emails. These 2,847 were: - Primary business emails (not aliases) - Active in last 90 days - Still at the company - Direct dial enriched (67% match rate) - Mobile numbers added (31% coverage) - Personal email backup (for job changes) Campaign results after 60 days: • Original 8,000: 27% bounce, 0.3% reply rate, domain blacklisted • Validated 2,847: 0.9% bounce, 4.7% reply rate, sender reputation intact One client saved $32K for this campaign by NOT burning through domains and IPs. Plus gaining a lot more responses compared to previous campaigns. In B2B, your sender reputation is your lifeline. You can't rebuild it with a credit card. What's your email validation process beyond "the vendor said it's verified"?

If 40% of your emails bounce, no amount of motivation or training will fix it. Imagine this: Monday morning, you’re reviewing your sales team’s performance. Numbers are down, replies are low, conversions have dropped. Your first instinct as a sales leader? “John’s not motivated enough.” “Sarah’s messaging needs work.” “Time for another training session.” But what if the problem isn’t mindset or skill this time? What if John’s emails are bouncing at 40%? What if Sarah’s inboxes are dead? What if half your sequences are landing in spam folders? No amount of role-playing will fix technical issues. I’ve seen this firsthand. If deliverability is broken, everything else: messaging, follow-ups, even personalization won’t matter. Your team’s hard work gets buried in spam. Here’s the shift I’d make: Use tools like Smartlead’s Global Analytics to uncover what’s REALLY happening. ⇾ Monitor inbox placement by rep. ⇾ Diagnose bounce rates in real-time. ⇾ Track spam flags across all campaigns. Suddenly, coaching conversations go from: “You need to work harder” to “Your domain setup is off—let’s fix it.” That’s a game-changer imo. The best sales leaders don’t just solve the obvious problems. They dig deeper. They use data. They fix the infrastructure. Because when you solve the RIGHT problems… your team wins.

Domain IP gone bad? Who’s REALLY to blame? (Its important to understand this if your cold emailing) You set up a new domain, start sending emails… and suddenly, your deliverability tanks. Your emails hit spam. Your domain reputation is in free fall. Who’s at fault? Let’s break it down 1) The Real Culprit? YOU (Mostly) Harsh truth: Most reputation issues come from how emails are sent. ❌ Sending too many emails too fast → Spam filters flag sudden spikes. ❌ Poor personalization & high spam complaints → Kills engagement, kills reputation. ❌ No warm-up → Cold-starting a domain without warming up is a disaster. Fix it: ✅ Start slow. Build gradually (no more than 50/day initially). ✅ Get replies. Low engagement = bad reputation. ✅ Use warm-up tools (SmartReach.io automates this for you). 2) Email Service Providers (ESP): The Enforcers 👀 Your Google Workspace, Outlook, Zoho, etc. own the sending infrastructure. They: ✔ Assign sending IPs. ✔ Monitor spam complaints. ✔ Decide if you land in inbox, spam, or promotions. 🚨 Too many complaints? They’ll throttle your sending or flag your domain. Fix it: ✅ Authenticate your domain (SPF, DKIM, DMARC—non-negotiable). ✅ Avoid spammy content (no “FREE MONEY” subject lines). ✅ Monitor engagement—if open/reply rates drop, pause & adjust. 3) Cold Email Software: Can Help (or Hurt) Cold email tools don’t own your sending IPs, but they impact your reputation: ✔ If they force good sending practices → Your domain stays safe. ❌ If they let you blast 1,000s of emails instantly → You’re at risk. Fix it: ✅ Use tools that enforce limits & warm-up (like SmartReach.io). ✅ Rotate multiple domains & inboxes for safer scaling. 4) Domain Providers: Not Guilty… Except When They Are 👀 They just sell domains—they don’t affect reputation. 🚨 But beware: Some resell bulk domains that already have a bad history. ❌ If you buy a flagged domain, you start with zero trust. Fix it: ✅ Buy from reputable providers (Google Domains, Namecheap, Cloudflare). ✅ Check domain history before purchasing (MxToolBox, Talos Intelligence). So, Who’s to Blame? ☑ Mostly the sender. ☑ Sometimes the ESP. ☑ Rarely the cold email software. ☑ Almost never the domain provider (unless they sold you a bad one). Ever had your domain reputation take a hit? What was the reason? Drop your experience in the comments. Lets learn from each other