How to Extract Nested Object Properties in Mixpanel Custom Event Property Creator?
is there a way I can extract a property within an object property in Mixpanel UI Custom event property creator?
is there a way I can extract a property within an object property in Mixpanel UI Custom event property creator?
Yes! You can extract a property from within an object property using the Custom Event Property creator. The documentation notes that the same index-based syntax used for lists also works with objects.
For example, if you have an object property like experiments = {"onboarding_v2": "control"}, you can reference a specific key within it using dot notation or index syntax directly in your custom property formula.
A practical approach mentioned in the docs is using the split or regex_extract functions to parse out values from string-based object properties, or simply referencing nested keys directly. [Custom Properties Use Cases]
Key things to know:
Direct key access: When building a custom property formula, you can use dot notation to access a key inside an object property (e.g., properties["experiments"]["onboarding_v2"]).
Object property limitations: Object properties are supported in core reports (Insights, Funnels, Flows, Retention, etc.) as filters and breakdowns, but property names (keys) within an object are not supported in Lexicon. [Data Types Overview]
Formula functions available: You can use functions like regex_extract, split, if, ifs, etc. within the custom property builder to further transform the extracted value. [Custom Properties Functions]
To create the custom property:
Click the + button next to the search bar in a report.
Select "Custom Event Property".
In the formula bar, reference your object property and the specific key you want to extract.
Apply or Save the property for reuse.
Note that the formula cannot exceed 20,000 characters in length. [Custom Properties Overview]
ℹ️ Tip: Mention @kapa.ai in the thread for follow-ups or DM the app for 1-to-1 help.
The knowledge sources don't explicitly document the exact syntax for accessing a nested key within an object property in the Custom Property formula builder. I want to be transparent about that rather than guess.
What the docs do confirm is a working pattern for extracting values from object-like string properties using functions available in the formula builder:
REGEX_EXTRACT – if your object property value is stored as a string, you can use a regex pattern to pull out a specific value. [Custom Properties Functions]
SPLIT – similarly useful for parsing structured strings. [Custom Properties Functions]
For example, the AB Tasty integration docs show a real-world use of REGEX_EXTRACT to pull a value out of a concatenated string property:
REGEX_EXTRACT(properties["AB Tasty"], "^\\[\\d+\\](.*?)(?=\\[\\d+\\])", 1)My recommendation:
Since the knowledge sources don't confirm that object["property"] or dot notation works in the Custom Property formula builder, I'd suggest:
Reaching out to Mixpanel Support directly for the confirmed syntax for object key access in custom properties.
As a workaround, if the object is stored as a string, use REGEX_EXTRACT or SPLIT to parse out the value you need.
I don't want to give you incorrect syntax that wastes your time — the docs are limited on this specific point.
ℹ️ Tip: Mention @kapa.ai in the thread for follow-ups or DM the app for 1-to-1 help.
Based on the knowledge sources available, I can confirm that Mixpanel supports Object properties (JSON key-value pairs), but the documentation is limited on the exact syntax for extracting a specific key's value within the Custom Property formula builder.
What the docs do confirm:
Object properties are supported in core reports as filters and breakdowns [Data Types Overview]
The Custom Property formula builder supports dot notation for accessing nested values in JQL queries (e.g., properties.experiments.onboarding_v2) [Transformations]
However, the knowledge sources do not explicitly document the confirmed syntax for extracting a specific key from a JSON object property within the Custom Event Property formula builder UI.
What I'd recommend:
Try dot notation in the formula bar: properties["your_object_property"]["your_key"] or properties["your_object_property"].your_key
If the value is stored as a string, use REGEX_EXTRACT to pull out the value associated with a specific key:
REGEX_EXTRACT(properties["your_object_property"], "\"your_key\":\"(.*?)\"", 1)For a definitive answer on the supported syntax, I'd recommend contacting Mixpanel Support directly, as the knowledge sources don't provide enough detail to confirm the exact approach for your use case.
ℹ️ Tip: Mention @kapa.ai in the thread for follow-ups or DM the app for 1-to-1 help.