Definition
Sender reputation is the trust score mailbox providers like Gmail, Yahoo and Microsoft keep for the people sending them mail. They track it for your sending domain and for the IP addresses your mail comes from. Domain reputation has become the more important of the two, because many senders share IPs through their email platform.
Providers do not publish the formula. The signals they are known to use include spam complaints, how often you hit addresses that do not exist, spam traps, whether your mail is authenticated with SPF, DKIM and DMARC, sending volume and consistency, and how recipients engage: opens, replies, moves out of spam, deletes without reading.
Why it matters
Reputation decides where your mail lands. Good reputation gets you to the inbox. Middling reputation means the promotions tab or spam folder. Poor reputation means throttling or outright rejection.
It is slow to build and quick to lose. A new domain has no history, which is why cold email teams warm up domains before sending at volume. A single campaign to an old, unverified list can push a healthy domain into the spam folder for weeks.
You can see part of the picture for free. Google Postmaster Tools shows domain reputation and your spam rate for Gmail traffic once you verify your domain and send enough volume. Microsoft offers SNDS for IP data. Blocklist lookups show whether your domain or IP has been listed.
How SimpleCold handles it
SimpleCold works on the list-quality part of reputation. Verifying addresses before you send removes the dead mailboxes and bad domains that produce hard bounces, and flags risky groups such as catch-all, disposable and role-based addresses so you can handle them carefully. It cannot fix complaints caused by content or targeting, and it cannot fix missing authentication.
To check whether your domain or IP is listed, use the free blacklist checker.
Related reading
- Sender reputation: what it is and how to fix it
- Email deliverability guide
- Email verification for cold email