Send a timstamp in JSON via Postman -

i'm new working rest apis , postman , i'm looking way include timestamp string in post request body via postman.

according postman docs, there dynamic variable {{$timestamp}} can used in request body. however, when try use it, 400 endpoint posting message "malformed data."

here couple of variations have tried:

variation 1

[     {         "from_number": "+123456789",         "messages": [             {                 "text":  "message at" {{$timestamp}},                 "to_number": "+123456789"             }         ]     } ] 

variation 2

[     {         "from_number": "+123456789",         "messages": [             {                 "text":  "message @ {{$timestamp}}",                 "to_number": "+123456789"             }         ]     } ] 

variation 3

[     {         "from_number": "+123456789",         "messages": [             {                 "text":  "message @ " + {{$timestamp}},                 "to_number": "+123456789"             }         ]     } ] 

all of these have returned same error

{   "errormessage": "malformed data",   "error": true } 

thanks @nims , @jaaulde: varation 2 correct answer. problem must have been typo.