How to Serialize a Class Object to JSON in Python

Changsin Lee
7 min readSep 11, 2021

Serializing your own class objects is quite straightforward in Python. Here are some tips.

· 1. Class Definition
· 2. Requirements
· 3. Solutions
Method 1: Use json.dumps() and __dict__
Method 2: Implement __str__ and __repr__
Method 3: Implement JSON Encoder
· 4. Handling complex objects
Method 4: Implement to_json() method
Method 5: Implement a custom to_json() method
· Conclusion

Photo by Claudio Schwarz on Unsplash

Serialization is the process of converting an object into a medium that can be saved and retrieved later: e.g., saving the state of an object into a file. For any mildly complex projects, serialization is something all developers have to do sooner or later. One of the nice things about the Python language is its ease of use in many common programming tasks. File IO, plotting diagrams, and accessing web contents are all easy with just a few lines of code. Serialization is also easy in Python, except when you are trying to serialize your own custom class. In this article, I want to share what I found to be the best practice in serializing your own class objects to JSON objects. The entire code sample is shared here.

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Changsin Lee

AI/ML Enthusiast | Software Engineer | ex-Microsoftie | ex-Amazonian