We have not implement s_vi in our website instead we are using fallback method and using s_fid cookie ,so my question are as follows.

1. Is it necessary to include s_vi cookie or s_fid will do.

2. How we implement s_fid cookie and s_vi

3. does not including s_fid causes  any inflation in our results?

Accepted Solutions (1)

Accepted Solutions (1)




What version of H code are you using?

s_fid is the fall back solution when s_vi can not be set. The situaion that is most common is due to locking occurring.

s_fid and s_vi, while not exactly interchangeable are still used as the u Kaur identifier for the row of data. So moving forward when you implement s_vi or ECID, etc it will still count the rows as unique rows and data would not have been lost. The new tracker will take the place of s_fid for users where it is currently set.

ECID or s_vi will take precedent over s_fid and no inflation would be seen.

Fallback ID Methods

Answers (4)

Answers (4)



Hey @chrism18776410

AMCV and AMCVS should take precedence over s_fid, so if your marketing cloud ID is being set properly, you shouldn't see the s_fid in a debugger, in my experience.

Sometimes this can happen if Appmeasurement.js loads before s.Visitor.js - you can check that in the console using the command "s_c_il":

Notice the order of the array:  0 = Visitor (s.Vistior.js), 1= Appmeasurement (Appmeasurement.js)


I'd give that a check quick to be safe

Let me know how you get on and if you need anything else



Thank you jharrington7897​!

I can confirm that the Appmeasurement.js is loading before s.Visitor.js when fid is fired and is not when mid is fired. This appears to be our issue.

Great lead.



To follow up here, if I have cookies set on a first-party domain for s_vi, s_fid, AMCV and AMCVS but my site is firing the Fallback ID from s_fid in the network call, what might be happening?

Assuming all of these primary Visitor IDs are present, but the call to metrics.domain.com uses the fid, will my unique visitors be inflated?