How is Sender Score calculated?
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If you've ever wondered why your Sender Score moved up or down without an obvious cause, it helps to understand what's actually being measured. Validity runs a network of email providers, ISPs, and filtering partners, and the score is built from the data that flows through that network every day.
Four signals do most of the heavy lifting in the calculation:
- Complaint rates. How often recipients mark your mail as spam via feedback loops. This is usually the fastest-moving signal. A spike in complaints can drop your score noticeably within the 30-day window.
- Unknown user rates. How often you're mailing addresses that don't exist. High bounce rates here signal a list hygiene problem, and Validity's network picks that up quickly.
- Spam trap hits. Sending to trap addresses (recycled or pristine) tells the network you're not maintaining your list carefully. Even a small number of trap hits carries weight because they're a strong signal of poor acquisition or stale data.
- Sending volume patterns. Sudden, unexplained spikes in volume look suspicious. Consistent, predictable sending is treated as a positive signal.
The whole calculation runs on a rolling 30-day window. That's actually good news. It means bad history fades, and genuine improvement shows up relatively quickly. If you cleaned your list and complaints dropped, you won't wait six months to see it reflected.
If you're trying to move the needle fast, complaint rate is usually the first place to look. A single high-complaint campaign can drag the score down more than weeks of clean sending can lift it. Spam trap hits are slower to accumulate but harder to shake, because they often point to a structural problem with how you're acquiring or aging your list.
Unknown user rate is the most fixable of the three. If you're seeing high bounce rates, a list clean will help quickly. You can run your list through RME Clean if you want to clear out invalid addresses before your next send. And if you want to check where your score sits right now, the next question covers how to check your Sender Score.
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