Link below is an example of creating 50 Iot devices, and implementing a Serverless AWS IoT Backend with AWS Lambda and Amazon DynamoDB. You can vary the devices to the number you like; It is done using the earlier version of AWS Iot Platform. Have a look.
https://aws.amazon.com/blogs/compute/implementing-a-serverless-aws-iot-backend-with-aws-lambda-and-amazon-dynamodb/
Here is the code to create 50 Iot Things
var AWS = require('aws-sdk');
AWS.config.region = 'ap-northeast-1';
var crypto = require('crypto');
var endpoint = "<endpoint prefix>.iot.<region>.amazonaws.com";
var iot = new AWS.Iot();
var iotdata = new AWS.IotData({endpoint: endpoint});
var topic = "registration";
var type = "MySmartIoTDevice"
//Create 50 AWS IoT Things
for(var i = 1; i < 51; i++) {
var serialNumber = "SN-"+crypto.randomBytes(Math.ceil(12/2)).toString('hex').slice(0,15).toUpperCase();
var clientId = "ID-"+crypto.randomBytes(Math.ceil(12/2)).toString('hex').slice(0,12).toUpperCase();
var activationCode = "AC-"+crypto.randomBytes(Math.ceil(20/2)).toString('hex').slice(0,20).toUpperCase();
var thing = "myThing"+i.toString();
var thingParams = {
thingName: thing
};
iot.createThing(thingParams).on('success', function(response) {
//Thing Created!
}).on('error', function(response) {
console.log(response);
}).send();
//Checking all devices were created
iot.listThings().on('success', function(response) {
var things = response.data.things;
var myThings = [];
for(var i = 0; i < things.length; i++) {
if (things[i].thingName.includes("myThing")){
myThings[i]=things[i].thingName;
}
}
if (myThings.length == 50){
console.log("myThing1 to 50 created and registered!");
}
}).on('error', function(response) {
console.log(response);
}).send();