Cold email is still one of the most effective ways to generate B2B leads. But if your emails land in spam, you're wasting time and money. The #1 reason cold emails fail isn't the copy — it's poor sender reputation.

That's where email warmup comes in. Warmup is the process of gradually building a positive sending history for your mailbox so Gmail, Outlook, and other providers trust you. Without it, even the best email will go straight to spam.

The technical side matters too: you need SPF, DKIM,...  mais