Email deliverability

Keep product, onboarding and outreach email reaching inboxes.

A diagnostic order for when mail goes to spam or does not arrive: authentication, list, content, volume and reputation.

Common reasons a message arrives late and what to check on the sending and receiving side.

Why a message sits in the outbox and a checklist of fixes.

What these messages mean and when to be careful.

What MX records are and how to interpret what a lookup returns.

The main causes of bounces and the changes that reduce them, in order of effect.

Outlook calls it Junk Email. Where to find it, how to rescue messages and how to reduce false positives.

A hard bounce is a permanent delivery failure, usually from an address that does not exist. Learn the causes and what to do next.

Deliverability is whether your email reaches the inbox, not just whether it is accepted. What affects it and how to start improving it.

Sender reputation is how mailbox providers rate your domain and sending address based on past behaviour.

SMTP authentication proves who you are to a mail server before it relays your message. It is not the same as SPF, DKIM or DMARC.

A message that never reaches the inbox earns nothing. The practical reasons to treat deliverability as part of the job.

Bounces, reputation and wasted effort: the practical reasons to verify addresses before you send.

A checklist for diagnosing a high bounce rate: list source, age, typos, authentication and sending changes.