If you’ve ever worked with web development or programming, you’ve probably come across the term “JSON” before. But what is a JSON file exactly, and how does it work? In this article, we’ll explore the basics of JSON files, JSON File format and how they are used in web development.
What is a JSON?
JSON stands for JavaScript Object Notation. It is a lightweight data interchange format that is easy for humans to read and write, and easy for machines to parse and generate. JSON was designed to be a simpler alternative to XML, which can be overly verbose and complex.
JSON Syntax
JSON has a very simple syntax. It consists of key/value pairs, which are separated by commas and enclosed in curly braces. Here’s an example:

In this example, “name”, “age”, and “city” are the keys, and “John Smith”, 30, and “New York” are the values. Keys and values are separated by a colon.
JSON also supports arrays, which are enclosed in square brackets and separated by commas. Here’s an example:
[ { “name”: “John Smith”, “age”: 30, “city”: “New York” }, { “name”: “Jane Doe”, “age”: 25, “city”: “Los Angeles” }]In this example, we have an array of two objects, each with their own set of key/value pairs.
How JSON is used?
JSON is used extensively in web development for data transfer between a client and a server. For example, when you submit a form on a website, the data is usually sent to the server as a JSON object.
In addition, many web APIs return data in JSON format. This makes it easy for developers to parse the data and use it in their own applications.
JSONL Files
JSONL (JSON Lines) is a format used for streaming JSON data. JSONL files contain one JSON object per line and are commonly used for handling large datasets. This format is useful for cases where it is not practical to load an entire JSON file into memory, such as when processing large data streams.
JSON File Extension
The file extension for JSON files is “.json”. When a file is saved with this extension, it indicates that the data inside the file is in JSON format. JSON files can be opened and edited with a text editor, making it easy to read and modify the data.
JSON Text Format
The JSON text format is a lightweight, human-readable syntax for representing data objects. JSON text consists of key-value pairs separated by commas and enclosed in braces {}. Each key is a string, and its value can be a string, number, object, array, boolean, or null. JSON text can also represent complex data structures such as nested objects and arrays.
JSON Data Files
JSON data files are used to store data in JSON format. These files can be used to transfer data between different systems or applications, and are commonly used in web development. JSON data files can be created and edited using a text editor or a specialized tool.
When creating a JSON data file, it is important to follow the JSON syntax rules. For example, keys must be enclosed in double quotes, and values can only be one of the valid JSON data types. It is also important to properly format the JSON data to make it more readable and easier to parse.
JSON File Format
JSON is a text-based format that is used to transmit data between different systems. It is often used in web applications to exchange data between the client and the server. The data in JSON format is represented using key-value pairs, making it easy to understand and parse.
JSON File Structure
JSON data is structured in a hierarchy, starting with objects at the top level. An object is defined using curly braces and contains one or more key-value pairs, separated by a comma. The key is a string that represents the name of the property, and the value can be any valid JSON data type, such as a string, number, object, or array.
Here’s an example of a simple JSON object:

In this example, the object has three key-value pairs. The “name” key has a string value of “John Doe”, the “age” key has a numeric value of 30, and the “city” key has a string value of “New York”.
JSON Format Example
Here’s an example of a more complex JSON object that includes nested objects and arrays:

In this example, the object has four key-value pairs. The “name” and “age” keys have the same values as the previous example, but the “address” key has a nested object with its own key-value pairs. The “phone_numbers” key has an array with two objects, each containing a “type” and “number” key-value pair.
Creating a JSON File
Creating a JSON file is simple. All you need to do is create a text file with the “.json” extension, and then populate it with your data using the JSON syntax.
Here’s an example of a simple JSON file:
JSON code
{ “name”: “John Smith”, “age”: 30, “city”: “New York” }
You can create more complex JSON files by including arrays, nested objects, and other data structures.
Reading a JSON File
Reading a JSON file is also simple. You can use a variety of programming languages to read a JSON file and parse its contents. Here’s an example using JavaScript:

In this example, we use the fetch() function to retrieve the contents of the “example.json” file. We then use the .json() method to parse the JSON data into a JavaScript object.
How to Open JSON Files
JSON files can be opened and edited with a text editor or a specialized JSON editor. A text editor such as Notepad or Sublime Text can open JSON files and display their contents in a readable format. Specialized JSON editors such as Visual Studio Code or Atom offer additional features such as syntax highlighting, code completion, and validation.
Prettify JSON
When working with JSON data, it can sometimes be difficult to read and understand the data structure. Prettifying JSON can make the data more readable by adding line breaks and indentation to the JSON text.
There are several tools available for prettifying JSON, including online JSON prettifiers and text editors with JSON formatting plugins. Some popular online JSON prettifiers include JSON Formatter and JSON Editor Online. For text editors, popular plugins include JSON Viewer and Pretty JSON.
JSON Standard
The JSON format is standardized by the Internet Engineering Task Force (IETF) in RFC 8259. The standard defines the syntax and structure of JSON, as well as rules for parsing and generating JSON data.
The standard specifies that JSON data must be represented as a collection of key-value pairs, where the keys must be strings and the values can be any valid JSON data type. It also defines rules for encoding and decoding JSON data, as well as guidelines for handling errors and exceptions.
JSON vs XML
JSON and XML (Extensible Markup Language) are both used for transmitting data between different systems, but they have some key differences. JSON is a more lightweight format that is easier to read and parse, while XML is more verbose and complex. JSON is also more commonly used in web applications, while XML is more commonly used in enterprise applications.
JSON vs GeoJSON
JSON and GeoJSON are both used for transmitting data between different systems, but they have some key differences. While JSON is a general-purpose format used to represent any kind of data, GeoJSON is a specific format used to represent geographic data.
GeoJSON extends the standard JSON format to include geographic information, such as latitude and longitude coordinates. It also includes support for additional geometry types, such as points, lines, and polygons. This makes it a useful format for representing geographic data in web applications and other software systems.
YAML vs JSON
YAML (YAML Ain’t Markup Language) is a human-readable data serialization format that is often compared to JSON. While both formats can be used for transmitting data between different systems, YAML has some key differences that make it a popular alternative to JSON.
One of the main differences between YAML and JSON is that YAML is designed to be more human-readable and easier to write. YAML uses whitespace and indentation to structure data, which can make it more intuitive to read and write than JSON. YAML also supports more complex data structures, such as lists and dictionaries, making it a more flexible format.
Conclusion
In conclusion, JSON is a widely-used data interchange format that is versatile and easy to use. JSONL files are useful for handling large datasets, while the JSON text format is a lightweight, human-readable syntax for representing data objects. JSON files can be opened and edited with a text editor or a specialized JSON editor. JSON data files are commonly used to store data in JSON format and can be created and edited using a text editor or a specialized tool.
While it is often compared to other formats like GeoJSON and YAML, it remains a popular choice for transmitting data between different systems. Understanding the differences between these formats can help you choose the best format for your specific use case.