Sales Loves Marketing

What is Sender Score?

Sender Score is a reputation rating from 0 to 100 for an email-sending IP address, calculated by the email company Validity (formerly Return Path). A higher score means the IP's recent sending looks more trustworthy compared with other senders.

By Sales Loves Marketing teamOriginally written by Joran HofmanUpdated

Sender Score is a number from 0 to 100 that rates the reputation of an IP address that sends email. It is calculated by Validity, which bought the company that created it, Return Path, in 2019. The higher the score, the more trustworthy the IP's recent sending looks compared with other senders.

How is Sender Score calculated?

Validity collects aggregate data from mailbox providers and filtering companies in its network and runs it through a proprietary model. The inputs it lists include:

  • Complaints: how often recipients mark your mail as spam.
  • Volume: how much you send and how steady it is.
  • Unknown users: how often you send to addresses that don't exist.
  • Rejected messages: how much mail receiving servers turn away.
  • External reputation: for example, listings on blocklists.

In most cases the score is a rolling 30-day average, so it reacts to recent behaviour but lags a little behind changes. It ranks your IP against other IPs, so it works more like a percentile than a grade.

Note: the old company name Return Path has nothing to do with the Return-Path email header.

Why does Sender Score matter?

Mailbox providers decide whether your email reaches the inbox, the spam folder or nowhere. Sender Score is not their decision, but it is a useful outside signal. A low or falling score usually points to the same problems that hurt your deliverability with Gmail, Outlook and others: complaints, bad addresses and blocklist listings.

It rates IP addresses, not domains. If you send through a shared IP from an email platform, the score reflects every sender on that IP, not just you.

How do you check your sender reputation?

  • Sender Score: enter your sending IP or domain on Validity's Sender Score site. It asks for your contact details first.
  • Google Postmaster Tools: shows how Gmail sees your mail, including spam rate, reputation, authentication and delivery errors. You verify your domain to use it.
  • Microsoft SNDS: gives data on individual IPs and junk reports for mail sent to Outlook.com.

How do you improve your Sender Score?

  • Authenticate your mail. Set up SPF, DKIM and DMARC. Gmail requires all three from senders of more than 5,000 messages a day.
  • Only email people who asked. Use clear opt-in, and confirm new addresses. Never buy lists.
  • Clean your list. Remove addresses that bounce and people who never engage.
  • Make leaving easy. A visible unsubscribe link and one-click unsubscribe cost you a subscriber instead of a spam complaint.
  • Keep complaints low. Gmail asks bulk senders to stay below a 0.3 percent spam rate.
  • Send steadily. Volume is one of the inputs, so avoid sudden spikes.

Frequently asked questions

How is Sender Score calculated?

Validity uses a proprietary model fed by data from mailbox and filtering providers in its network. Its published inputs include spam complaints, sending volume, unknown users, rejected messages and external reputation. In most cases scores are based on a rolling 30-day average.

What is a good Sender Score?

Higher is better, on a scale from 0 to 100. Validity does not publish an official pass mark. Use the score to spot a trend or a sudden drop, then look at complaints, bounces and blocklists to find the cause.

Do Gmail and Outlook use Sender Score?

Sender Score is Validity's own rating, built from its network's data. Mailbox providers judge senders with their own systems. Google Postmaster Tools and Microsoft SNDS show you how Gmail and Outlook.com see your mail.