The Importance of HTTP Status Codes in Microservice and API Development

Recently, I had a small argument with a colleague who suggested that one of our developers should determine whether a request failed or succeeded based on the returned string—specifically, whether it was empty or not. While this might seem like a straightforward approach, I strongly believe that decisions should be based on HTTP status codes, not the content of the response string. Here’s why.

The Role of HTTP Status Codes

HTTP status codes are issued by a server in response to a client’s request. They fall into various categories, each serving a specific purpose:

2xx (Success): Indicates that the client’s request was successfully received and processed. 3xx (Redirection): Suggests that further action needs to be taken to complete the request. 4xx (Client Error): Signifies that the client seems to have made an error. 5xx (Server Error): Indicates that the server failed to fulfill a valid request.

Why Are They Important?

Clarity and Consistency: Using standard HTTP status codes makes it easier for developers to understand the outcome of an API call without having to dig into the response payload.

Debugging and Troubleshooting: Status codes can quickly point developers to the root cause of an issue, whether it’s a client-side mistake or a server-side error.

Automation: Automated systems can easily interpret these codes and take appropriate actions, such as retrying a failed request or logging an error for future investigation.

Monitoring and Analytics: Tracking the frequency of various status codes can provide valuable insights into API health and usage patterns.

User Experience: Proper use of status codes can help in creating a more responsive and user-friendly application by handling different scenarios gracefully.

Best Practices

Use the most specific status code for each operation. For example, use 201 Created for resource creation and 204 No Content for a successful delete operation.

Avoid using generic status codes like 200 OK for all successful operations, as it doesn’t provide enough context about what happened in the server.

Always include a message body to elaborate on the status code, especially in the case of client and server errors.


HTTP status codes are an integral part of API and microservice development. They offer a standardized way to communicate the status of HTTP requests, making it easier for both humans and machines to understand what’s happening. By using HTTP status codes effectively, developers can build more robust, efficient, and user-friendly applications.

So, the next time you find yourself in a debate about whether to use status codes or response strings to indicate the outcome of an API call, remember the many benefits that come with sticking to standard HTTP status codes. It could make all the difference in your project’s success.