The SDK start call response returns the variables that have changed for the user - Have the SDK pass this response to your backend. Start call response
Translating IDs into readable formats
Next you may want the ability to map these numeric variant ids into human-readable names.
Leanplum provides an API that gives you information on translating Variant IDs back into human-readable names. The most comprehensive API call is getAbTests.
This will return information about all A/B Tests and Variants for a specific app. From this information, you can determine that 6331369890775040 is "Variant 1" in "Test A" and 5702495255396352 is "Control" in "Test B".