User ID Power-Up

Cookies get blocked, shortened and deleted, so the same visitor can look like a new one on every visit. The User ID power-up gives your server container another way to recognise a returning visitor: an anonymous ID calculated from the request itself.

How the ID is made

The FlyNode User ID variable takes the visitor's IP address, user-agent and the hostname of the request, adds the secret salt of your container, and hashes them (SHA-256). The same visitor on the same network and browser gets the same ID. Nothing is stored: it is calculated for each request, inside your container.

Set it up

1. Open your container, go to Power-Ups and turn on User ID. A salt appears.
2. Download the FlyNode User ID template from the power-up.
3. In your server container open Templates, then Variable Templates, New, the three-dot menu and Import. Choose the file and save.
4. Go to Variables, create a new variable of type FlyNode User ID and paste your salt.
5. Use the variable where you need an ID: as user_id or external_id on your tags, or as a key in the Data Store.

The salt belongs to one container: the same visitor gets a different ID in another container. Keep the salt unchanged so the IDs stay the same.

What to expect

• It is a fallback, not a replacement for a first-party cookie (see Cookie Keeper). The ID changes when the visitor's IP address, browser or the hostname changes, for example when a phone moves from Wi-Fi to mobile data.
• Several people behind one office network with the same browser can share an ID.
• To measure the effect, compare your remarketing audience size and returning-user numbers for 2 to 4 weeks before and after.
• The optional Accept-Language box makes the ID a little more specific.