Загрузите JSON из File RobotFramework
*** Settings ***
Library Collections
Library ExtendedRequestsLibrary
Library OperatingSystem
*** Variables ***
${uri} https://blabla.com/service/
${json_path} C:/home/user/project/src/json/
*** Test Cases ***
Robot Test Case
Create Session alias ${uri}
&{headers} Create Dictionary Content-Type=application/json; charset=utf-8
${json} Get Binary File ${json_path}nameOfJsonFile.json
${resp} Post Request alias data=${json} headers=${headers}
Should Be Equal As Strings ${resp.status_code} 200
Relieved Rhinoceros