JSON vs YAML, Which Data Serialization Is Better?

Any developers or programmers, or even marketers would not feel strange to a data type – JSON. It’s one of the most popular and awesome data serialization language. In fact, there is an alternative called YAML. I believe people who is famiilar with Google ads API must know this data type. In this Python knowledge hub, I would elaborate what are their pros and cons respectively, and how you can better leverage them as a developer and marketer.

json vs yaml

Any developers or programmers, or even marketers would not be strange to the data type – JSON. It’s one of the most popular and awesome data serialization languages. In fact, there is an alternative called YAML. I believe people who are familiar with Google ads API must know this data type. In this Python knowledge hub, I would elaborate what are their pros and cons respectively, and how you can better leverage them as a developer and marketer.

JSON vs YAML – What is JSON

Although most of us know what JSON is, let’s have a quick introduction. JSON is the short name for JavaScript Object Notation. This data type is based on a subset of JavaScript programming language standard ECMA-262 3rd Edition-December 1999. JSON is widely used with JavaScript but since it is language-independent, it can be used with any programming language.

JSON has a standard format for data storage. It stores data in key and value pairs. The records are separated by commas and both field names and strings are enclosed with double quotes. Tons of platforms and channels like Google, WeChat, etc leverage JSON to communicate with client-side and server-side. One of the most popular applications is API data transfer.

For more details regarding JSON converter, please check out this article

Python Tutorial 48: JSON, XML Converters to CSV, SQL, Google Sheets Data into JSON, XML

JSON vs YAML – What is YAML

YAML is the short name for yet another markup language. It uses three dashes (—) to indicate the start of a document and three dots (…) to indicate the end of a document. Unlike JSON, YAML uses indentations just like in Python to show the levels in the data. The key and value pairs are separated with a colon and the lists begin with a hyphen in YAML. And also YAML files are written with the extension YML in some places and both.YAML and. YML means the same file type.

Take Newyork Times API for example. Its API specification documentation is in the YAML format. People can transfer the API spec information to others using YAML.

json vs yaml

JSON vs YAML pros and cons

JSON and YAML are not as simple to compare as we think. But in terms of the purpose of both language, essentially both data serialization language aims to provide easier communication and human-readable interchange language.

Data Serialization Performance

In the data serialization contest, JSON is the winner because of the ability to quickly and easily parse JSON serialized data with its simpler design. And this has made JSON more popular among developers which results in more and more native support and this has improved the performance once again.
Therefore JSON has become the most widely used data interchange format for web applications and web services.

Winner: JSON


Although JSON is the winner of data serialization, it doesn’t mean the battle is over. As a data serialization language, readability and complexity are also critical.

The design goal of JSON is to be as simple as possible and be universally usable. In contrast, the design goal of YAML is to provide a good human-readable format and provide support for serializing arbitrary native data structures. This has increased the readability of the YAML files, but it has made the parsing and generation of files somewhat complex.

We can see this clearly on the YAML official website where it shows the content in YAML format: It is easily readable for anyone visiting the site. On the other hand, if it was displayed in JSON format, the webpage would be useless.

There is a saying that YAML is a superset of the JSON format. We can parse JSON using a YAML parser. However, in practical scenarios, this parsing may raise problems, so it is theoretically possible.

Winner: Tie

Capability to Implement Advanced Data Structures

Another feature that YAML provides is the ability to reference other data objects. With this referencing, it is possible to write recursive data in the YAML file.
Because of this, people can define anchors in the YAML file using & and refer to them later using aliases, *. This is a very important feature in YAML that JSON does not offer.

In JSON, it is impossible to serialize complex structures with object references. But the above feature in YAML solves that problem, although it has one drawback of this which is the possibility of infinite looping in some converters.

Winner: YAML

Developer Library and Discussion

For any programming language, we can easily find a JSON library and stack flow discussion that integrates with any language. It’s thanks to its popularity, its ease of implementation, and simplicity. Also, the majority of APIs are using JSON to implement the data interexchange. The JSON official website lists many languages with many supporting libraries for JSON.
On the other hand, although YAML also has widespread support and many libraries for integrating it with various languages, but not as much as JSON. You can get the list of libraries and languages that support YAML here.

Winner: JSON


Currently, we discussed the pros of JSON and YAML are tied. But some considerably important features of YAML that JSON doesn’t have. Its YAML supports comments where JSON does not.

We can comment anywhere in the document with a simple # character. This has proven advantageous when writing configuration files where one developer can easily describe the configuration using the comments. Therefore YAML format is used in many technology stacks like ElasticSearch, and Docker for storing configuration information.

Winner: YAML

Wrap up

So from all these points, we can see that both JSON and YAML have their own strengths and weaknesses. A good developer should be able to identify these and use the correct format in the correct place.


Q1: What is the difference between JSON and YAML?

A: JSON and YAML are both data interchange formats, but they have some differences. JSON is a more widely supported format and is used primarily for transmitting data between a server and a web application. YAML, on the other hand, is a human-readable format and is often used for configuration files. JSON uses a stricter syntax and requires quotes around keys and string values, while YAML allows for more flexibility and does not require quotes. Additionally, JSON supports a wider range of data types, including numbers, booleans, and null, while YAML has a more limited set of data types.

Q2: Which format is better for eCommerce websites?

A: Both JSON and YAML can be used for eCommerce websites, depending on the specific needs and requirements of the website. JSON is a more common format and is generally easier to work with, especially when it comes to integrating with APIs and other systems. However, YAML can be a good choice if readability and ease of editing are important factors, as it has a more human-friendly syntax. Ultimately, the best format for an eCommerce website will depend on the specific use case and the preferences of the development team.

Q3: Can JSON and YAML be used together?

A: JSON and YAML can be used together in certain scenarios. For example, it is possible to convert data from JSON to YAML and vice versa using appropriate libraries or tools. This can be useful when migrating data between systems or when different parts of a project require different formats. However, it is important to note that there may be some limitations or differences in how the data is interpreted or handled between the two formats, so careful consideration should be given to ensure compatibility and consistency.

Q4: Is JSON or YAML more secure?

A: Neither JSON nor YAML have inherent security features, as they are primarily designed for data interchange and not for security purposes. However, it is important to implement proper security measures when working with either format, such as validation and sanitization of input data, to prevent vulnerabilities like injection attacks or data tampering. Additionally, it is crucial to follow best practices for secure data transmission and storage, regardless of the chosen format.

Q5: Which format is more efficient in terms of file size?

A: In terms of file size, JSON and YAML can have different efficiencies depending on the specific data and the way it is structured. JSON tends to have more compact syntax and generally results in smaller file sizes compared to YAML. However, YAML allows for more human-readable and expressive data structures, which can sometimes result in larger file sizes. It is important to consider the specific use case and the trade-offs between file size and readability when choosing between the two formats.

Q6: Can JSON or YAML be used for SEO optimization?

A: Neither JSON nor YAML are directly used for SEO optimization. However, both formats can be used to structure data in a way that is more easily understood by search engines. For example, JSON-LD (a variant of JSON) is commonly used for adding structured data markup to webpages, which can improve visibility and understanding of the page content by search engines. Similarly, YAML can be used to organize and structure metadata or configuration files that influence SEO factors, such as URL structure or site navigation.

Q7: Are there any limitations or compatibility issues when using JSON or YAML?

A: Both JSON and YAML have their own limitations and compatibility considerations. JSON has a stricter syntax and does not support certain advanced features or data types that YAML does. On the other hand, YAML can be more forgiving and flexible, but this can also lead to potential compatibility issues when working with different systems or libraries. It is important to consider the specific requirements and constraints of the project and ensure that the chosen format aligns with the supported capabilities and integration points.

Q8: Which format is more commonly used in eCommerce platforms?

A: JSON is more commonly used in eCommerce platforms due to its widespread support and compatibility with various systems and APIs. Many eCommerce platforms and APIs provide JSON as the default or preferred data format for integration and data exchange. However, this does not mean that YAML cannot be used in eCommerce platforms. Some platforms may offer support for YAML or allow for customization and configuration using YAML files. Ultimately, the choice of format may depend on the specific platform and its capabilities.

Q9: Can JSON or YAML affect the website’s loading speed?

A: Both JSON and YAML can potentially affect a website’s loading speed, but the impact is generally minimal. The file size and complexity of the data structure can have a more significant impact on loading speed than the format itself. However, it is good practice to optimize and compress data files, regardless of the format, to minimize the impact on loading speed. Additionally, other factors such as server response time, caching mechanisms, and network conditions can also influence the overall loading speed of a website.

Q10: Is it possible to convert JSON to YAML or vice versa?

A: Yes, it is possible to convert data from JSON to YAML or vice versa using various tools and libraries. There are online converters available that can perform the conversion, as well as programming libraries in various programming languages that provide functions or methods for converting between the two formats. It is important to note that the conversion process may require some manual adjustments or considerations, especially if the data structures or features of the formats are not fully compatible.