Error response structure in Rest API - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of this JSON error response?

Given this REST API error response JSON, what is the value of the error.message field?

Rest API

{
  "error": {
    "code": 404,
    "message": "Resource not found",
    "details": "The requested item does not exist."
  }
}

A "Resource not found"

B "404"

C "The requested item does not exist."

D "error"

💡 Hint

Look inside the error object for the message key.

The message key inside the error object holds the string describing the error, which is "Resource not found".

🧠 Conceptual

intermediate

Which HTTP status code is most appropriate for a validation error?

When a REST API receives invalid input data, which HTTP status code should it return to indicate a validation error?

A 200 OK

B 404 Not Found

C 400 Bad Request

D 500 Internal Server Error

💡 Hint

Think about which status code means the client sent bad data.

400 Bad Request means the client sent invalid data, so it is the correct status code for validation errors.

❓ Predict Output

advanced

What error does this JSON cause when parsed?

Consider this JSON error response. What error will a JSON parser raise?

Rest API

{
  "error": {
    "code": 401,
    "message": "Unauthorized access",
    "details": "Missing authentication token"
  }
}

A SyntaxError due to trailing comma

B KeyError for missing key

C TypeError due to wrong data type

D No error, parses correctly

💡 Hint

Check the commas after the last item in JSON objects.

JSON does not allow a comma after the last key-value pair in an object. The trailing comma causes a SyntaxError.

❓ Predict Output

advanced

What is the output of this error response handling code?

Given this Python code snippet that processes an error response, what will be printed?

Rest API

response = {
    "error": {
        "code": 403,
        "message": "Forbidden",
        "details": None
    }
}

message = response.get("error", {}).get("message", "No error message")
print(message)

A No error message

B KeyError

C None

D Forbidden

💡 Hint

Look at how the code safely accesses nested keys with get.

The code safely gets the "message" key inside "error". Since it exists, it prints "Forbidden".

🧠 Conceptual

expert

Which error response structure best supports internationalization?

To support multiple languages in error messages, which JSON error response structure is best?

A { "error": { "code": 500, "message": null } }

B { "error": { "code": 500, "messages": { "en": "Internal server error", "es": "Error interno del servidor" } } }

C { "error": { "code": 500, "message": ["Internal server error", "Error interno del servidor"] } }

D { "error": { "code": 500, "message": "Internal server error" } }

💡 Hint

Think about how to store messages in multiple languages clearly.

Option B uses a dictionary with language codes as keys, making it easy to select the right message for each user language.