Resolving JSON.stringify Issues in Axios Requests to .NET Core APIs

A comprehensive guide to understanding and fixing issues when sending JSON payloads from the frontend to .NET Core APIs using Axios.
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Understanding and Fixing JSON.stringify Issues in Axios Requests

When working with front-end technologies and APIs, it’s not uncommon to encounter issues that can leave developers scratching their heads. One such issue arises when sending JSON data through Axios to a RESTful .NET Core API. Many developers have reported that using JSON.stringify(obj) in their requests leads to unexpected behavior, particularly with how the API interprets the payload.

In this post, we’ll explore a common scenario involving a JavaScript object, how to properly send this using Axios to a .NET Core API, and provide a clear, comprehensive solution for effective communication between your frontend and backend.

The Problem

The developer faces an issue with the following code snippet when sending a request from the frontend to the API:

[[See Video to Reveal this Text or Code Snippet]]

In their .NET Core API, they have a method defined as follows:

[[See Video to Reveal this Text or Code Snippet]]

The problem arises when the frontend’s JSON string does not correctly pass through to the API, resulting in the API blocking the request. Even when the API accepts other strings, it does not recognize the payload sent as a string via JSON.stringify, leaving the developer puzzled.

Key Observations

This inconsistency causes confusion, as JSON.stringify should indeed return a valid string representation of an object.

The Solution

Step 1: Adjusting Axios Request

To properly send JSON data, you need to specify the content type in the headers of the Axios request. This is critical because Axios does not automatically set the Content-Type header for string payloads. Use the following format:

[[See Video to Reveal this Text or Code Snippet]]

Step 2: Modifying the API Endpoint

Instead of accepting a string and manually deserializing it, a cleaner approach would be to allow the API to directly bind to your object model. You can modify the controller method as follows:

[[See Video to Reveal this Text or Code Snippet]]

Step 3: Sending Directly for Improved Readability

Finally, update your Axios call to send the JavaScript object without converting it to a string manually. This is achieved simply by:

[[See Video to Reveal this Text or Code Snippet]]

Conclusion

By making these adjustments—setting the proper Content-Type header on your requests and allowing your API to bind directly to the object model—you can streamline the process of sending JSON data from your frontend to your backend.

This approach not only resolves the immediate issue at hand but also enhances code maintainability and readability. Working with JSON is expected to be seamless, and understanding how data flows between systems is crucial for any developer.

By adopting these strategies, you can effectively troubleshoot similar issues in the future and continue building more robust applications. Happy coding!