Question
Why are array properties mapped in Segment Connections destination mappings sent as strings instead of being retained as arrays?
Product
Twilio Segment
Environment
Segment Console
Answer
The behavior and formatting of mapped properties are ultimately controlled by the destination mapping. So, even if the source sends a field as an array, the property can be transformed into a string depending on the destination mapping.
For Segment Connections destinations, data extracted from a Reverse ETL source in array form and mapped into properties is transformed into a string. This is expected behavior.
As a workaround, you can use a Source Insert Function attached to the source configured in the Segment Connections destination to parse the value back into an array before Segment processes the event.
Additional Information
For more information, see the Source Insert Functions documentation.