cURL
curl --request POST \ --url https://api-staging.respondent.io/v1/messaging/conversations/{conversationUid}/participants \ --header 'Content-Type: application/json' \ --header 'x-api-key: <x-api-key>' \ --header 'x-api-secret: <x-api-secret>' \ --data '{ "participantUserId": "<string>" }'