 Okay, so JSON has been around us for a while and as a result the use of JSON in almost all of the modern application has become widespread. But there are a couple of mistakes that developers may make when working with JSON. Now as we know that JSON has no schema, so for JSON what we can do is only syntax validation. And if you want both schema and syntax validation then you need to go for XML. As XML have XSD file or say XML schema definition file using which you can perform XML schema validation. So let's jump in and go over with some common mistakes. Alright, so first let's start with some simple JSON over here. Let me define the key value pair in this JSON object. And then let us log this object in the browser console. Now let us run this file using this option. Okay, so over here you can see our patient object. Now as we know that in JSON you have to have double quotes around both the key and the value. But when you are working with standard JavaScript object you usually don't. So this is perfectly valid JSON and you can see it successfully logged in the browser console. But now let's validate this JSON in online JSON validator tool. So let me copy it and when I paste it over here it says this is not a valid JSON. So as you can see in the error message that it is expecting a string in this key. So if I add double quotes over here then you can see that now it becomes a valid JSON. Alright, now what if I define this key in single quote instead of double quotes. So once again over here we are getting the same error and it says it expecting string which means single quote is also not allowed in JSON file. You have to use double quotes to define key and their values. Alright, and the next is JSON has no particular date time data type. So if I add say patient DOB like this and in month instead of this if I write 33 and in date if I write 55 then JSON never tell you that this is not a valid date or time. So you have to have validated this type of date time value in your application. Okay and another thing is the first character of JSON text must be either curly brace or if it is an array then it should be a square brace. So any other character over here is considered as invalid. Say for example instead of this curly brace if I add this small bracket then you can see here that it is started throwing an error. Alright, now the next is the set of unique object. It means the set of unique object is one thing that is notably missing from JSON. For example in this JSON if I copied this object and add it again over here then this JSON object can potentially violate the set uniqueness. But from the syntax validation point of view this JSON is totally a valid JSON file. But today many modern JSON parser throws an error when you have this type of duplicate key in your JSON file. Okay, now in the previous module video we have learned and created one this is history JSON file. So now in the JSON file I have committed some mistakes. Now let's once again study the JSON file and see what kind of mistakes I did in the JSON file and how this online JSON validated tool help us to get rid of that common errors and mistakes.