The StackMail Blog
Cold email infrastructure tips, deliverability guides, and everything you need to scale outbound.
How Many Domains Do You Need for Cold Email in 2026?
The right number of domains depends on your sending volume, target audience, and risk tolerance. Here's a framework to figure out what you need.
Cold EmailSPF, DKIM, and DMARC Explained Simply
Email authentication doesn't have to be confusing. Here's a plain-English explanation of the three DNS records every cold emailer needs.
DNS & Authentication5 Email Warmup Mistakes That Kill Deliverability
Most people rush through warmup or skip it entirely. Here are the five most common mistakes and how to avoid them.
DeliverabilityGoogle Workspace vs Microsoft 365 for Cold Email: Which One?
Both providers work great for cold email, but each has distinct advantages. Here's an honest comparison to help you decide.
Cold EmailNew: One-Click Export to 15+ Cold Email Sequencers
Export your mailbox credentials to Instantly, SmartLead, Saleshandy, and more with a single click. No more copy-pasting IMAP settings.
Product UpdatesThe Complete Cold Email Infrastructure Checklist
A step-by-step checklist covering everything from domain purchase to first campaign send. Bookmark this one.
GuidesWhy Your Cold Emails Land in Spam (And How to Fix It)
Spam folder placement is rarely about one thing. Here are the most common causes and actionable fixes for each.
DeliverabilityHow Agencies Should Set Up Cold Email Infrastructure at Scale
Managing cold email infrastructure for multiple clients requires a different approach. Here's how top agencies structure their setup.
Cold Email