EmailKnow:How I stopped my own inbox from inflating my open rate — with a hash, not an IP

Small, annoying problem with a nice constraint-driven answer.

When you send a tracked email and then open it yourself — to check it looks right — that fires my tracking pixel. Now your "someone read it!" stat is inflated by... you. Every honest tracker has to solve this, or the numbers lie.

The obvious fix: record the opener's IP and ignore opens from the sender's IP. But storing recipients' IP addresses is exactly the kind of creepy-tracker behavior EmailKnow exists to avoid. An IP is personal data. I don't want it in my database at all.

So the constraint became the design: never store an IP, but still tell "this open is the sender" from "this open is someone else."

The trick is a one-way hash. At send time, I hash the sender's IP with a secret salt — SHA-256(ip + salt) — and store only that hash. When a pixel later fires, I hash that opener's IP the same way and compare. Match → it's the sender opening their own email → label it "self" and exclude it from the real-open count. No match → a genuine third party.