aws api gateway - SerializationException in posting new Records via Dynamodb Proxy Service in API -

i getting

"__type": "com.amazon.coral.service#serializationexception" 

as reply in postman & in test console in api gateway

trying post record directly dynamodb using api proxy services.. referring aws article - https://aws.amazon.com/blogs/compute/using-amazon-api-gateway-as-a-proxy-for-dynamodb/

here's mapping

{      "tablename": "tablenamegoeshere",     "item": {     "id" : "$context.requestid"     "eventname" : "$input.path('$.eventname')",     "timestamp" : $input.path('$.timestamp'),     "answers": "$util.parsejson($input.path('$.answers'))"     } } 

update: did asked ... , worked if try add array of json objects gives me above same error - here's trying now. please - couldnt find on google well

#set($inputroot = $input.path('$')) {      "tablename": "answer",     "item": {     "id": {             "s": "$context.requestid"             },     "eventname": {             "s": "$input.path('$.eventname')"             },     "timestamp" : {             "n": "$input.path('$.timestamp')"             },     "answers": {             "s": "$input.path('$.answers')"             },     "line": {     "s" : "[ #foreach($elem in $inputroot.line)     {       "questionid" : "$elem.questionid",       "answer" : "$elem.answer"     }#if($foreach.hasnext),#end  #end   ]" }     } } 

to address challenge of having array of objects part of payload.

for request payload

{     "emailid": "v@a.com",     "responses": [         {             "question": "q1",             "answer": "a1"         },         {             "question": "q2",             "answer": "a2"         }     ] } 

template be

#set($inputroot = $input.path('$')) {     "tablename": "customers",     "item": {         "leadid": {             "s": "$context.requestid"         },         "emailid": {             "s": "$input.path('$.emailid')"         },         "responses": {             "l": [            // list type             #foreach($elem in $inputroot.responses) // loop thru array                 {                     "m": {        // map type                         "answer": {                             "s": "$elem.answer"                         },                         "question": {                             "s": "$elem.question"                         }                     }                 }                 #if($foreach.hasnext),#end             #end             ]         }     } } 

integration response template (similar structure request)

#set($inputroot = $input.path('$')) {   "$results": [     #foreach($elem in $inputroot.items)     {       "emailid": "$elem.emailid.s",       "responses": [           #foreach($resp in $elem.responses.l)           {            "question": "$resp.m.question.s",            "answer": "$resp.m.answer.s"           }           #if($foreach.hasnext),#end           #end       ]     }     #if($foreach.hasnext),#end     #end   ] }