$ man deliverability

Deliverability

Whether your emails actually land in the inbox (not spam, not promotions, not nowhere).

I learned this the hard way. when I was an SDR, I sent 200+ emails a day from primary domains with zero warmup. no one told me about deliverability. I thought if the email sent, it worked. then I started checking spam folders. half my emails were there. I was torching my domain reputation and didn't even know it. now I obsess over deliverability before I obsess over copy. because the best email in the world doesn't matter if no one sees it.

I check MX records before routing contacts to email platforms. Google Workspace domains go to Instantly (because that's where I have Google-only sending infrastructure). Non-Google domains go to HeyReach on LinkedIn because I can't reliably deliver to Microsoft 365 or other providers from my Instantly setup. I also monitor bounce rates. If a campaign hits >5% hard bounces, something's broken upstream — usually the email provider or MX routing. I learned to fix the plumbing before I write the copy.