Simplified ID Merge
Call out to check ID management version in settings and link to Original doc
Overview
- System use user_id to manipulate distinct_id
Usage
If using our Web/Mobile SDKs or a CDP like Segment or Rudderstack, there are only 2 steps:
- Call
.identify(<user_id>)
when a user signs up or logs in. Pass in the user's known identifier (eg: their ID from your database). - Call
.reset()
when a user logs out.
Any events prior to calling .identify
are considered anonymous events. Mixpanel's SDKs will generate a $device_id
to associate these events to the same anonymous user. By calling .identify(<user_id>)
when a user signs up or logs in, you're telling Mixpanel that $device_id
belongs to a known user with ID user_id
. Under the hood, Mixpanel will stitch the event streams of those users together. This works even if a user has multiple anonymous sessions (eg: on desktop and mobile). As long as you always call .identify
when the user logs in, all of that activity will be stitched together.
Mechanism
- talk about the device_id in detail
$device_id
- autogenerated by client-side SDK and attached to all events
- this becomes distinct_id attached to event if $user_id not present
- all events should have this property
- aka anonnymous ID
$user_id
- Calling identify SDK function sets the
user_id
value passed to the function as the $user_id for all events moving forward $user_id
will always becomes distinct_id for the event whenever it is present- when
$user_id
and$device_id
are detected in the same event for the first time, merge occurs
Example User Flows
- Charlie example.
Mimic below but update to Original ID Merge
Let's walk through a few user flows where ID Merge is useful, and when to call .identify()
and .reset()
to use ID Merge properly.
Note: these flows walk through how distinct_id
is set in Simplified ID Merge; in Original ID Merge, the value of distinct_id
is not deterministic. See the FAQ for more details on how distinct_id
is set.
New User Signup
-
A user lands in your product on a new device and interacts with your product before signing up. Our SDK will assign the user a random
$device_id
and persist it. All events tracked at this point will send only a$device_id
.Event $device_id $user_id distinct_id (set by Mixpanel) Notes 1 D1 $device:D1 2 D1 $device:D1 -
The user returns later and signs up for your product. You call
.identify(<user_id>)
. All events sent after this point are tracked with both the original$device_id
and the new$user_id
. Mixpanel will retroactively set the$user_id
on any prior events with the user’s$device_id
so that both event streams are joined.Event $device_id $user_id distinct_id (set by Mixpanel) Notes 1 D1 $device:D1⇒ U1Retroactively updated 2 D1 $device:D1⇒ U1Retroactively updated 3 D1 U1 U1 Links D1 ⇒ U1
Returning User
-
The user from the previous flow returns, but is on a new device and has not logged in yet.
Event $device_id $user_id distinct_id (set by Mixpanel) Notes 1 D1 $device:D1⇒ U12 D1 $device:D1⇒ U13 D1 U1 U1 Links D1 ⇒ U1 4 D2 $device:D2 New device D2 5 D2 $device:D2 -
The user logs in. Call
.identify(U1)
to tell us that the user on this device is the same$user_id
we have seen before.Event $device_id $user_id distinct_id (set by Mixpanel) Notes 1 D1 $device:D1⇒ U12 D1 $device:D1⇒ U13 D1 U1 U1 Links D1 ⇒ U1 4 D2 $device:D2⇒ U1Retroactively updated 5 D2 $device:D2⇒ U1Retroactively updated 6 D2 U1 U1 Links D2 ⇒ U1
Multiple Users, One Device
-
A first user begins using a new device.
Event $device_id $user_id distinct_id (set by Mixpanel) Notes 1 D1 $device:D1 -
The user logs in. Call
.identify(U1)
, which links the$device_id
to their$user_id
.Event $device_id $user_id distinct_id (set by Mixpanel) Notes 1 D1 $device:D1⇒ U1Retroactively updated 2 D1 U1 U1 Links D1 ⇒ U1 -
The user logs out. At this point, you should call
.reset()
, or manually generate a new$device_id
if you are managing it yourself. A new user shows up and tracks events using this new$device_id
.Event $device_id $user_id distinct_id (set by Mixpanel) Notes 1 D1 $device:D1⇒ U12 D1 U1 U1 Links D1 ⇒ U1 3 D2 $device:D2 Reset generated new ID: D2 4 D2 $device:D2 -
This new user (U2) now logs in. Call
.identify(U2)
.Event $device_id $user_id distinct_id (set by Mixpanel) Notes 1 D1 $device:D1⇒ U12 D1 U1 U1 Links D1 ⇒ U1 3 D2 $device:D2⇒ U2Retroactively updated 4 D2 $device:D2⇒ U2Retroactively updated 5 D2 U2 U2 Links D2 ⇒ U2
Limitations
- cannot link 2 anon user_id
- cannot have 2 $user_id in a cluster
- no $merge for fixing mistakes
- $merge profile direction not predictable
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