Lambda function that writes web-hooks to S3. You will also need to set up an API gateway to trigger this function.

index.js

var AWS = require('aws-sdk');
var s3 = new AWS.S3();

var uuidv4 = function() {
    return 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.replace(/[xy]/g, function(c) {
        var r = Math.random() * 16 | 0,
            v = c == 'x' ? r : (r & 0x3 | 0x8);
        return v.toString(16);
    });
}

exports.handler = async(event) => {
    var bucketName = process.env.bucketName;
    var folderName = process.env.folderName;
    var key = folderName + "/" + uuidv4();
    var params = { Bucket: bucketName, Key: key, Body: JSON.stringify(event) };

    return await s3.upload(params).promise();
    
};