Human-readable error messages in Rest API - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of this REST API error response?

Consider a REST API that returns this JSON error response when a user tries to access a resource without permission.

{
  "error": {
    "code": 403,
    "message": "Access denied: You do not have permission to view this resource.",
    "details": "User role 'guest' lacks 'read' permission."
  }
}

What is the message field in this error response?

A Unauthorized access attempt detected.

B Access denied: You do not have permission to view this resource.

C Permission error: guest role cannot read.

D Error 403: Forbidden access.

💡 Hint

Look for the exact text in the message field of the JSON.

The message field contains the human-readable explanation of the error. Here, it clearly states: "Access denied: You do not have permission to view this resource."

❓ Predict Output

intermediate

What HTTP status code is returned for a missing resource?

A REST API returns this JSON error when a requested item is not found:

{
  "error": {
    "code": 404,
    "message": "Resource not found: The requested item does not exist.",
    "details": "Item ID 12345 not found in database."
  }
}

What is the HTTP status code in this error response?

A 500

B 401

C 400

D 404

💡 Hint

Check the code field inside the error object.

The code field shows the HTTP status code. Here it is 404, which means 'Not Found'.

❓ Predict Output

advanced

What is the user-friendly error message for invalid input?

A REST API returns this error JSON when the user sends invalid data:

{
  "error": {
    "code": 422,
    "message": "Invalid input: 'email' field must be a valid email address.",
    "details": "Value 'user_at_example.com' is not a valid email format."
  }
}

What is the exact message shown to the user?

A Invalid input: 'email' field must be a valid email address.

B Error 422: Unprocessable Entity.

C Email format error: user_at_example.com is invalid.

D Input validation failed for email.

💡 Hint

Focus on the message field for the user-friendly explanation.

The message field provides a clear, human-readable explanation: "Invalid input: 'email' field must be a valid email address."

❓ Predict Output

advanced

What error message does this REST API return for server failure?

When the server encounters an unexpected error, it returns this JSON:

{
  "error": {
    "code": 500,
    "message": "Internal server error: Please try again later.",
    "details": "NullReferenceException at line 42."
  }
}

What is the message field value?

A NullReferenceException occurred.

B Server error 500: Unexpected failure.

C Internal server error: Please try again later.

D Service unavailable, try again.

💡 Hint

Look for the exact text in the message field.

The message field gives a user-friendly message: "Internal server error: Please try again later." The technical details are in the details field.

❓ Predict Output

expert

What is the exact error message returned when authentication fails?

A REST API returns this JSON when authentication fails:

{
  "error": {
    "code": 401,
    "message": "Authentication failed: Invalid API key provided.",
    "details": "API key 'abc123' is not recognized."
  }
}

What is the exact message field value in this error response?

A Authentication failed: Invalid API key provided.

B Error 401: Unauthorized access.

C API key abc123 is invalid.

D Access denied due to invalid credentials.

💡 Hint

Check the message field for the user-friendly error text.

The message field clearly states: "Authentication failed: Invalid API key provided." This is the human-readable error message.