What are reputation databases?

Think of a reputation database like a credit score system, but for email senders. Every time you send, various services are quietly taking notes on your behavior. High complaint rates? That's a ding. Spam trap hits? Another mark against you. Strong engagement? That helps. These services store all of it, and mailbox providers consult those records before deciding where your email lands.

Reputation databases track signals like IP and domain history, spam complaint rates, spam trap hits, bounce rates, and engagement patterns. The databases aren't all the same, though. Each one collects different signals and serves different parts of the filtering ecosystem.

The main ones you'll hear about are:

• Spamhaus. One of the most influential blocklist operators in the world. Getting listed here can cut your deliverability across huge swaths of the internet.
• Validity Sender Score. Gives your sending IP a numeric score from 0 to 100. It's not a blocklist, but many filters use it as an input when evaluating inbound mail.
• Talos Intelligence. Cisco's threat intelligence system, which includes email reputation data used by many enterprise filtering solutions.
• Barracuda Reputation. Feeds into Barracuda's own filtering products, widely used by businesses and schools.
• Gmail's internal reputation. Completely proprietary, not visible to senders directly, but very much real. Gmail tracks your behavior against its own users and makes delivery decisions based on that data alone.

Here's the part that catches people off guard. Your reputation exists in multiple databases at the same time, and they don't talk to each other. Good standing with Gmail tells you nothing about your status on Spamhaus. A blocklisting on one database might not even show up in another. So if your emails are suddenly hitting the spam folder somewhere, it's worth checking several sources before you assume you know the cause.

You can check your domain and IP against the most common blocklists with our free Blocklist Checker. It's a good first stop when something feels off with your deliverability. And if you're seeing issues across multiple databases at once, our SOS hotline is free and we actually pick up.