handler.js

import { SFNClient, StartSyncExecutionCommand } from "@aws-sdk/client-sfn";

const region = process.env.AWS_REGION;
const stateMachineArn = process.env.STATE_MACHINE_ARN;

const client = new SFNClient({ region });

export const handler = async (event) => {
  const params = {
    stateMachineArn,
    input: JSON.stringify({ key: 'hello' }),
  };
  
  const command = new StartSyncExecutionCommand(params);

  try {
    const data = await client.send(command);
    console.log("Success", data);
    return {
      statusCode: 200,
      body: JSON.stringify({ message: 'Success!', data }),
    };
  } catch (err) {
    console.error("Error", err);
    return {
      statusCode: 500,
      body: JSON.stringify({ message: 'Error', error: err.message }),
    };
  }
};

great sir