null vs missing key in REST API Response [closed]

Question

Closed. This question is opinion-based. It is not currently accepting answers.

---

Want to improve this question? Because this question may lead to opinionated discussion, debate, and answers, it has been closed. You may edit the question if you feel you can improve it so that it requires answers that include facts and citations or a detailed explanation of the proposed solution. If edited, the question will be reviewed and might be reopened.

Closed 10 years ago.

Improve this question

Say in my application, some users give us their last name, and others do not. In a REST API response, which body is preferred:

With a "null" value:

{"firstName": "Bob",
 "lastName": null}

Or just a missing key:

{"firstName": "Bob"}

Answer 1

Consider removing empty or null values.

If a property is optional or has an empty or null value, consider dropping the property from the JSON, unless there's a strong semantic reason for its existence.

{
 "volume": 10,
 // Even though the "balance" property's value is zero, it should be left in,
 // since "0" signifies "even balance" (the value could be "-1" for left
 // balance and "+1" for right balance.
 "balance": 0,
 // The "currentlyPlaying" property can be left out since it is null.
 // "currentlyPlaying": null
}

Further Reading
Google Style Guide - Empty or Null Property Values
Should null values be included in JSON responses from a REST API?

• jtmarmon: thanks for the link, Robert. so even if currentlyPlaying will be in some responses and not other, it's preferrable to have the client check if the key is there or not rather than check if it's null?
• Robert Harvey: null and undefined have almost the same meaning in Javascript, and you can check for both using if (myProperty == null)
• jtmarmon: well actually in my case the client might be java, objective-c, or javascript. the link within the second link (API-craft) indicates to me that null fits our semantic use case, but mostly that I should just make a decision and stick to it :P thanks again
• gnasher729: Simple: If the application needs to distinguish between different values, then the server must provide different values, otherwise it need not and should not. Does your app need to distinguish between a key not being present, a key have an empty string as a value, and a key having a null value?
• Dave New: The answer in this post addresses some good reasons as to why you should not remove null fields.