Email insights and deliverability

Deliverability is not a setting you switch on. It is a reputation you accumulate, and the things that damage it are mostly about who you send to rather than what you send.

This is what to watch and what to do about it.

Who this is for

Anyone sending at volume — marketing, outreach, and admins responsible for the sending domain.

Before you start

• A connected sending mailbox.
• Ideally an authenticated sending domain — see the domain article, because unauthenticated mail is the most common reason for landing in spam.

Complaints and hard bounces are the signals that matter
Open rates go up and down for reasons that have nothing to do with your reputation. Complaints — people marking you as spam — and hard bounces to addresses that do not exist are what mailbox providers actually judge you on. Those two are worth reacting to immediately; a soft dip in opens is usually not.

Keep sending healthy

1. Authenticate your sending domain first
   Unauthenticated mail is treated with suspicion regardless of content. This is the single highest-value thing to fix, and it is a one-time job.
2. Watch bounces and complaints, not just opens
   Bounced and complained addresses are recorded as suppressions. A rising count there is a real warning; a wobbly open rate usually is not.
3. Never send to a list you did not build
   Purchased and scraped lists produce complaints and hard bounces at a rate that damages your domain for every other message you send, including one-to-one mail from reps.
4. Warm up gradually if you are new
   A brand-new domain suddenly sending thousands of messages looks exactly like a spammer. Build volume up rather than starting at the top.
5. Respect unsubscribes immediately
   Unsubscribes are recorded as suppressions and are honoured on subsequent sends. Trying to work around that is both a legal problem and a reputational one.
6. Review before every large send
   Check the audience is who you think it is and the message is what you think it is. Most deliverability damage is done in one careless send, not gradually.

What you get

• A sending reputation that holds up over time.
• Early warning from the metrics that actually predict trouble.
• Suppression handled automatically for unsubscribes, bounces and complaints.
• Fewer messages quietly landing in spam where nobody sees them.

Frequently asked questions

My open rate dropped. Is my deliverability broken?

Probably not. Open rates move for many reasons, including image blocking that has nothing to do with you. Look at bounces and complaints instead — those are what providers judge.

What is the single most effective thing I can do?

Authenticate your sending domain. Unauthenticated mail is treated with suspicion no matter how good the content is, and it is a one-time fix.

Can I send to a list I bought?

Don't. It produces complaints and hard bounces at a rate that damages the domain for all your mail, including individual messages your reps send.

What happens to an address that hard bounces?

It is recorded as a suppression so you stop sending to it. Continuing to send to addresses that do not exist is one of the clearest negative signals you can produce.