Definition
Email deliverability is the measure of how much of your mail actually reaches recipients' inboxes. It is related to, but different from, delivery rate.
- Delivery means the receiving server accepted the message. It did not bounce.
- Deliverability, or inbox placement, means where it went after that: the inbox, a promotions tab, or the spam folder.
A campaign can have a 99% delivery rate and still land mostly in spam. Your sending platform sees the first number. The second is much harder to measure, which is why seed tests and Postmaster Tools exist.
Why it matters
Mail in the spam folder is rarely read. For cold email especially, deliverability decides whether a sequence works at all, and problems tend to compound. Poor placement leads to fewer replies, fewer replies look like low engagement, and low engagement pushes more mail into spam.
Four things decide most of it:
- Authentication. SPF, DKIM and DMARC set up and aligned. Gmail and Yahoo have required this of bulk senders since February 2024.
- Reputation. The history mailbox providers keep for your domain and IPs.
- List quality. Few bounces, no spam traps, contacts who expect to hear from you.
- Content and engagement. Relevant messages, sensible volume, easy unsubscribe, a low complaint rate.
How SimpleCold handles it
SimpleCold covers one of those four: list quality. It verifies addresses before you send, removes the ones that would bounce, and flags the risky groups (catch-all, disposable, role-based, no response) with reasons so you can decide how to treat them. That keeps hard bounces low, which protects reputation.
It does not set up your authentication, write your copy or warm your domains. For the DNS side, the free SPF, DKIM and DMARC checkers show what is published.