If your site knows who a visitor is by their email address or phone number, you probably don’t want that value travelling anywhere. The BumbleB tag can hash it in the visitor’s browser, so the raw value never leaves the page.
A hash is a one-way scramble: the same email always turns into the same string of characters, but you can’t turn the string back into the email. That means Crunch can still tell that two visits came from the same person, without ever seeing who they are.
What you’ll need
- A Google Tag Manager connector that is already set up — see Google Tag Manager tag.
- Access to edit your Google Tag Manager container, because you’ll paste the tag code again.
Step by step
- In the hub, open Connectors and find your GTM connector’s card.
- Under the tag code, set Hash user id in the page to the option that matches your user ID:
- No, send it as the site sets it — for an internal ID that isn’t personal, like an account number.
- Yes, it is an email — the email is trimmed and lowercased, then hashed. Lowercasing first
means
Ana@Example.comandana@example.comhash the same way. - Yes, it is a phone number — the number is reduced to
+and digits, then hashed, so spaces and dashes don’t change the result.
- Copy the tag code again and re-paste it into Google Tag Manager, then publish the container. The setting lives in the code itself, so changing it in the hub alone does nothing.
Good to know
- The hash is SHA-256, a widely used standard.
- Heads up: if a browser can’t compute the hash — for example on a page not served over HTTPS — the user ID is left out rather than sent raw.
When you need it
Turn it on when you also sync a database that holds the same people. The on-prem sync connector can hash its email or phone column the same way, so the two line up without either side ever sending the raw value.
Related
- Google Tag Manager tag — the tag this setting belongs to.
- On-prem sync connector — bring in a database with matching hashes.
- Two datasets, one question — ask across your site and your database.