Adventures in Machine Learning

Tips for Handling and Validating Invalid JSON Strings

Handling Invalid JSON Strings

JSON (JavaScript Object Notation) is a lightweight format used to store, exchange, and retrieve data between web servers and clients. It’s concise and easy to read, making it popular among developers.

However, sometimes invalid JSON strings are generated, and it becomes difficult to handle them. In this article, we will cover some commonly used techniques to handle invalid JSON strings.

Escaping Double Quotes

Double quotes are integral parts of JSON syntax. They are used to enclose string values, property names, and other values in JSON.

In some cases, however, the double quotes can cause issues while parsing and generating JSON strings. One way to deal with the double quotes issue is to escape them.

Escaping double quotes is done by adding a backslash (\) before the double quotes in the string. For example, to represent the string “Hello, World!” in a JSON string, we can escape the double quotes like this:

{“message”: “Hello, \”World!\””}

The backslash () tells the JSON parser to treat the following quote as part of the string instead of closing the string.

Escaping double quotes is essential when adding string values to JSON data.

Raw String Declaration

Another approach to handle invalid JSON strings is by declaring raw strings. A raw string is a literal string that doesn’t interpret special characters.

They allow us to specify a string value as it is, without processing escape characters. In Python, to define a raw string, we can prefix a string with the letter r.

For example, to declare a string containing the word “C:folder”, we can use the raw string format like this:


This way, raw strings prevent errors caused by invalid escape sequences and hidden characters.

Writing JSON Manually

The JSON module in Python comes with a method called JSON.dumps(). Its used to convert Python objects to JSON formatted strings.

However, sometimes, despite using this method, we can encounter syntax errors while coding a JSON array. In such cases, the best approach is to write JSON strings manually.

Writing JSON manually allows us to have complete control over the JSON format, and we can avoid syntax errors that arise during automatic JSON serialization. The only downside to writing JSON manually is that it might be a tedious and time-consuming process for large datasets.

Syntax Errors in JSON Array

JSON Arrays are used to store multiple values in a single variable. They are surrounded by square brackets [ ] and separated by commas.

In an array, elements have a specific index starting from 0. Sometimes, the JSON array can encounter issues like missing commas or unquoted property names, among other syntax issues.

In such cases, we can run the JSON array through a JSON validator to identify and fix the invalid syntax.

Declaring Key-Value Pairs in JSON Object

A JSON object is a collection of key-value pairs where a key is followed by a colon(:) and then the value. They are denoted by curly braces { } and separated by commas.

JSON objects can also contain nested objects and arrays. During creating JSON objects, incorrect syntax can occur.

The best way to avoid issues while creating JSON objects is to declare key-value pairs correctly. Its essential to ensure that each property key has a corresponding value and that the keys are enclosed in quotes.

Fixing Invalid JSON on the Backend

When sending data over HTTP, a JSON string can become invalid if it wasn’t properly parsed or serialised. Handling invalid JSON strings can be challenging, but its possible to fix it on the backend.

When receiving a JSON error, its advisable to perform an HTTP request debug or error trapping to capture the invalid JSON string. Once the invalid JSON string has been identified, it can be fixed by parsing and validating the data, then creating new JSON strings as appropriate.

Its crucial to remember that invalid JSON strings can severely affect server performance.

Validating and Correcting JSON Strings

When handling JSON data, it’s essential to validate and correct it to ensure that its valid, compatible, and ready for use. Here are some commonly used techniques for validating and correcting JSON strings:

Using a JSON Validator

One of the easiest ways to validate JSON strings is to use an online JSON validator. A JSON validator checks the syntax of a JSON string, ensuring that it follows the correct format for keys, values, arrays, objects, etc.

The validator also checks for incorrect values, formats, and syntax errors.

Example of a Complex JSON String

Complex JSON strings can be difficult to validate and correct manually. Heres an example of a complex JSON string with nested objects and arrays:


“employees”: [


“id”: 1,

“name”: “John Doe”,

“roles”: [




“tasks”: [


“id”: 101,

“title”: “Budget Planning”,

“status”: “In Progress”



“id”: 102,

“title”: “Sales Reporting”,

“status”: “Completed”





“id”: 2,

“name”: “Jane Doe”,

“roles”: [




“tasks”: [


“id”: 103,

“title”: “GUI Development”,

“status”: “In Progress”



“id”: 104,

“title”: “Bug Fixing”,

“status”: “Completed”







In conclusion, JSON strings are critical for transmitting and exchanging data, but they can contain invalid syntax that can cause challenges while handling them. By utilizing the techniques discussed above, like escaping double quotes, declaring key-value pairs correctly, and validating JSON strings, we can handle invalid JSON strings in a concise and straightforward manner.

Proper handling of JSON strings not only ensures that we can transmit data efficiently but also saves time and improves server performance. In conclusion, handling and validating JSON strings are essential steps in ensuring efficient data transmission.

This article provided insights and techniques for handling invalid JSON strings such as escaping double quotes, declaring key-value pairs correctly, and validating JSON strings. It is crucial to handle syntax errors properly to avoid server performance issues and time wastage.

Takeaway points include using online JSON validators, declaring raw strings, and manually writing JSON data. Overall, proper handling and validation of JSON strings create a smooth data transmission process, which is critical to the success of web development projects.