There's a difference between delivery and deliverability. Delivery means the receiving server accepted your email. Deliverability means it actually reached the inbox — not spam, not the promotions tab. Even "successfully delivered" mail can sit unseen in spam.

What affects email deliverability?

Three things carry most of the weight: authentication (SPF, DKIM, and DMARC that prove you are who you say you are), sender reputation (your track record with mailbox providers), and list hygiene (sending to engaged, opted-in subscribers). Spam complaints and hard bounces drag all three down.

What's a good deliverability rate?

Aim for 95% or higher. Real-world inbox placement often hovers around 83–85%, so there's usually room to improve. Google now expects spam complaint rates under 0.3%.

How do you improve it?

Authenticate your domain, warm new sending domains gradually, remove inactive subscribers, use double opt-in, and make unsubscribing easy — a clean list beats a big one.