The expected request structure for our Lambda, based on the request POJO, is as follows:

{
 "name" : "Heartin",
 "time" : "Morning"
}

The request payload sent from the client via the POST request is as follows:

{
 "user" : {
 "name" : "Heartin"
 },
 "greeting" : {
 "time" : "Morning"
 }
}

We can map the request payload to the expected JSON format by using the following mapping template:

{
 "name" : $input.json('$.user.name'),
 "time" : $input.json('$.greeting.time')
}