What is sender reputation, and what damages it?

Sender reputation is how much mailbox providers trust mail from your domain and mailbox. Learn what builds it, what damages it and how to check it.

Updated October 11, 20262 min read

Sender reputation is the trust mailbox providers place in mail from you, built from how your past emails were received. A good reputation makes inbox placement more likely. A poor one pushes your emails toward spam or gets them rejected, even when the email itself is fine.

What reputation is attached to

Providers track reputation at several levels:

Your domain, the part after the @ in your From address, and the domain that signs your email with DKIM.
The sending servers (IP addresses). When Distro sends, your email goes out through Google's own mail servers from your mailbox. Google manages those servers, so your domain and your own sending behaviour matter most.
Your Google account and mailbox, including how Google itself sees your sending activity.
Links and domains inside the email. A link to a domain with a bad history can count against you.

Distro sends from your own Google account and does not use a shared sending pool, so other Distro users' sending does not affect your sending servers. Read How Distro sends email.

What builds a good reputation

Recipients reply, keep your emails and move them out of spam.
Few bounces, because you send to real, current addresses.
Very few spam reports.
Steady, predictable volume that grows gradually.
Correct authentication: SPF, DKIM and DMARC.

What damages it

Cause	Why it hurts
Spam reports	The clearest sign recipients did not want your email. See Handling spam complaints.
High bounce rates	Suggests old, guessed or bought lists. See Why emails bounce.
Sudden volume spikes	Looks like a compromised or spam account.
Sending to purchased or scraped lists	Leads to bounces, spam traps and complaints.
Missing authentication	Providers can't confirm the mail is really yours.
Ignoring opt-outs	Annoyed recipients report spam instead.
Low engagement	Emails nobody opens or answers suggest they are unwanted.
Shortened or suspicious links	Shared shortener domains often carry an abuse history.

How to check your reputation

Google Postmaster Tools. Google offers free dashboards for domain owners, including spam rate and authentication results for mail sent to Gmail users. You verify your domain first, and data only appears once you send enough mail to Gmail recipients, so it may stay empty at low cold-email volumes.
Microsoft offers programs for senders to its consumer mailboxes. Check Microsoft's current sender documentation.
Public blocklists. Several services let you check whether a domain is listed. A listing is worth investigating, though not every list affects every provider.
Your own results in Distro. Watch Bounced, Unsubscribed and replies on Analytics. A sudden drop in replies on a campaign that used to work is often the first sign.