What is the difference between YAML and JSON ; when prefer one than another

Question

Hi,

When we prefer to use YAML over JSON and vice versa considering following things :

• Performance(the encode/decode time)
• memory consumption.
• expression clarity
• library availability , easy of use (prefer C)

I was planning to use one of these two in our embedded system to store configure files. Thanks.

Related:

Should I use YAML or JSON to store my Perl data?

Answer 1

I find YAML to be easier on the eyes: less parenthesis, "" etc. Although there is the annoyance of tabs in YAML... but one gets the hang of it.

In terms of performance/resources, I wouldn't expect big differences between the two.

Futhermore, we are talking about configuration files and so I wouldn't expect a high frequency of encode/decode activity, no?

Answer 2

If you don't need any features which YAML has and JSON doesn't, I would prefer JSON because it is very simple and is widely supported (has a lot of libraries in many languages). YAML is more complex and has less support. I don't think the parsing speed or memory use will be very much different, and maybe not a big part of your program's performance.

Answer 3

Technically YAML is a superset of JSON. This means that, in theory at least, a YAML parser can understand JSON, but not necessarily the other way around.

See the official specs, in the section entitled "YAML: Relation to JSON".

In general, there are certain things I like about YAML that are not available in JSON.

• As @jdupont pointed out, YAML is visually easier to look at. In fact the YAML homepage is itself valid YAML, yet it is easy for a human to read.
• YAML has the ability to reference other items within a YAML file using "anchors." Thus it can handle relational information as one might find in a MySQL database.
• YAML is more robust about embedding other serialization formats such as JSON or XML within a YAML file.

In practice neither of these last two points will likely matter for things that you or I do, but in the long term, I think YAML will be a more robust and viable data serialization format.

Right now, AJAX and other web technologies tend to use JSON. YAML is currently being used more for offline data processes. For example, it is included by default in the C-based OpenCV computer vision package, whereas JSON is not.

You will find C libraries for both JSON and YAML. YAML's libraries tend to be newer, but I have had no trouble with them in the past. See for example Yaml-cpp.