How We Actually Fixed Cold Email Deliverability (And What We're Still Doing)

Deliverability isn't a problem you solve once. It's a problem you solve, then re-solve, then solve again at the next level of scale. That's the honest version of what we've learned running cold email infrastructure across 32,000+ sending accounts and $8M+ in client revenue. Here's the actual stack we landed on, and why each piece is there.

We Tried a Lot of Things Before This Worked

There was no single "aha" moment. We switched domain providers. We worked with reseller accounts. We tested different sending setups. Most of it was trial and error, and I'd be lying if I said we had a clean roadmap from the start.

What we do have now is a repeatable foundation. Four components: where we buy domains, which ESPs we use, how we handle IP reputation, and how we verify inbox placement before we scale anything.

Why We Buy Domains From Porkbun

We purchase our domains through Porkbun. Pricing is straightforward, the registrar doesn't carry the same baggage as some of the bigger names that cold emailers have burned through over the years, and it fits cleanly into a high-volume purchasing workflow.

Domain selection matters more than most people admit. The registrar you use, the age of the domain, the TLD, all of it feeds into how mailbox providers perceive you before a single email is sent. Porkbun gives us a clean starting point without unnecessary friction.

Splitting Between Microsoft and Google on Purpose

We run a mix of Microsoft and Google workspaces. This isn't arbitrary. Each ESP has its own filtering logic, its own deliverability quirks, and its own ceiling for what it'll tolerate at volume. By splitting across both, we keep our options open.

If one provider tightens its policies or a batch of accounts starts degrading, we're not fully exposed. We can shift volume, test what's working on the other side, and optimize accordingly. Think of it as not putting all your sending eggs in one basket, except the basket is a major email provider that can shut you down without warning.

This also means we can run real comparisons. If inbox placement drops on Google accounts but holds on Microsoft, that tells us something. It's data we wouldn't have if we were mono-ESP.

Parking Our IP Address

One of the techniques we're using now is IP parking through EmailGuard. The idea is straightforward: before you send anything at scale, you want your IP address to have a clean, established reputation. Parking it, letting it sit and build history without blasting cold volume through it immediately, helps with that.

This is the kind of infrastructure detail that gets skipped when people are eager to start sending. It feels like wasted time. It isn't. A burned IP is a much bigger problem to fix than a slow ramp.

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Using EmailGuard to Confirm Inbox Placement

The other thing EmailGuard does for us is confirm where our emails are actually landing. Not where we think they're landing, where they're actually landing, across Microsoft Outlook and SMTP providers.

This matters because your open rate is not a deliverability metric. Emails can go to spam and still get opened occasionally. The only way to know if you're in the inbox is to test it directly, at scale, with a tool built for that purpose.

We run these checks continuously. Not once during setup, not quarterly, continuously. Deliverability shifts. A domain that was clean last month can start drifting. Catching that early is the difference between a fixable problem and a dead sending account.

The Mindset That Actually Makes This Work

Here's what I'd say to anyone who's frustrated with deliverability right now: treat it as a learning curve, not a ceiling. Every time something breaks, you find out something true about how the system works. That knowledge compounds.

We didn't build this stack in a week. We built it by running into problems, figuring out why they happened, and adding the right piece of infrastructure to prevent them next time. The teams that scale cold email successfully are the ones that stay curious about the technical side instead of treating it as someone else's problem.

Deliverability is not a set-it-and-forget-it layer. It's an ongoing discipline. The good news is that once you have a real system, tested domains, split ESPs, parked IPs, continuous inbox verification, you're operating with a structural advantage over everyone who's still guessing.

Key Takeaways

• Buy domains from Porkbun for a clean, low-friction starting point at volume.

• Split sending across both Microsoft and Google workspaces to reduce ESP-specific risk and enable real comparisons.

• Park your IP address before scaling volume, use EmailGuard to build reputation before you send.

• Use EmailGuard continuously to verify actual inbox placement across Outlook and SMTP providers, not just at setup.

• Treat deliverability as an ongoing discipline, not a one-time fix. The infrastructure compounds over time.

Frequently Asked Questions

Why does BuzzLead use both Microsoft and Google for cold email sending? Running a mix of both ESPs reduces exposure if one provider tightens its policies or a batch of accounts degrades. It also creates a natural testing environment, if inbox placement holds on one side but drops on the other, that's actionable data.

What does "parking an IP address" mean in cold email? It means letting your IP build a clean sending history before you push volume through it. Rather than starting cold sends immediately on a new IP, you allow it to establish reputation first. This reduces the risk of triggering spam filters right out of the gate.

Why use EmailGuard specifically? EmailGuard serves two functions in this stack: it helps park and establish IP reputation, and it confirms actual inbox placement across Microsoft Outlook and SMTP providers. Open rates alone won't tell you where your emails are landing, you need a dedicated tool for that.

How often should you check deliverability? Continuously, not just at setup. Deliverability shifts over time. A domain or sending account that was clean last month can start drifting, and catching that early keeps a small problem from becoming a dead account.