Amazon connect chat API session starts without the use of AWS credentials

Currently, our approach updating the AWS configuration and initiating the amazon connect session with nodejs as follows:

const AWS = require("aws-sdk");
AWS.config.update({
  accessKeyId: "accessKeyId",
  secretAccessKey: "secretAccessKey",
  region: "region"});

new AWS.connect() and initiate a new AWS.connectParticipant()

Our objective is to avoid using the AWS SDK for initiating the customer side chat session to send and receive messages. Instead, we are interested in utilizing the REST API directly, using the InstanceId and ContactFlowId.

Is there any way to achieve this goal?