5 Ways to Reduce YAML File Size
Posted on
July 18, 2023
•
5 min read
TL;DR:
Learn the pros and cons of 5 simple ways to reduce YAML file size and why you should care.
Are you working with YAML files that seem to be growing exponentially, causing headaches when you try to manage, read, or edit them? If so, you're in the right place!
In this post, we'll discuss five simple yet effective ways to reduce the size of your YAML files. We'll walk you through each approach, highlighting the benefits and drawbacks and providing relevant code examples to help you get started. So let's dive in!
Why Should You Care About YAML File Size?
Before we start exploring the solutions, it's essential to understand why large YAML files can be problematic. As your YAML files grow, they can become:
- Slower to parse and load.
- More difficult to read and understand.
- More prone to errors due to increased complexity.
- More work to manage, especially when collaborating with others.
By reducing the size of your YAML files, you'll improve their performance and make them easier to work with. So let's explore five methods to help you shrink those YAML files down to size.
1. Eliminate Redundancy by Using Anchors and Aliases
YAML files can become significant when there's a lot of repeated information. To tackle this issue, you can use YAML anchors and aliases to define reusable content and prevent duplication.
How It Works
Anchors are created using the & symbol, followed by a name, while aliases are denoted by the * symbol, followed by the anchor name. You can define an anchor in one part of your YAML file and then refer to it with an alias in other parts of the file.
Example
Let's say you have a YAML file that includes repeated information about different products:
You can eliminate the redundancy by creating an anchor for the description:
Now, the description is only defined once, reducing the file size.
Pros and Cons
Pros:
- Reduces file size by eliminating redundancy.
- Makes the file easier to read and manage.
Cons:
- Requires some manual work to identify redundant information.
- Can become confusing if overused or not appropriately organized.

2. Use Compact Notation
YAML offers a compact notation called flow style, which can help reduce the file size by using less whitespace and fewer line breaks. This can be especially helpful for small or simple YAML files.
How It Works
YAML has two styles: block and flow. Block style is the default and more human-readable, while flow style is more compact. To use flow style, you can use curly braces ({}) for dictionaries and square brackets ([]) for lists.
Example
Here's a YAML file in block style:
And here's the same content in flow style:
As you can see, the flow style uses fewer lines and less whitespace, reducing the file size.
Pros and Cons
Pros:
- Reduces file size by using a more compact notation.
- Can be helpful for small or simple YAML files.
Cons:
- Can be less human-readable and harder to understand.
- Might not be suitable for complex or large YAML files.
3. Remove Unnecessary Comments and Whitespace
Comments and extra whitespace can add to the file size, especially in large YAML files. While comments can help you understand and maintain the YAML file, you can sometimes reduce the file size by removing unnecessary comments and whitespace.
How It Works
Go through your YAML file and identify any comments or extra whitespace that can be removed without affecting the file's readability or functionality. Be cautious when doing this, as you want to keep useful information and make the file easier to read.
Example
Here's a YAML file with comments and extra whitespace:
Pros and Cons
Pros:
- Reduces file size by removing unnecessary content.
- Can make the file easier to read if comments and whitespace are excessive.
Cons:
- Requires manual work to identify and remove unnecessary content.
- Can reduce readability or understanding if valuable comments are removed.
4. Split YAML Files into Smaller Modules
Breaking down large YAML files into smaller, more focused modules can make them more manageable and easier to work with. This approach is beneficial when dealing with complex configuration files or when working with a team.
How It Works
Identify parts of the YAML file that can be logically separated into standalone modules. Once you have done this, create new YAML files for each module and import them into the main YAML file using the appropriate include mechanism for your programming language or framework.
Example
Let's say you have a YAML file with multiple sections:
You can split it into three separate files: database.yaml, logging.yaml, and cache.yaml. Then, in your main YAML file (e.g., config.yaml), you can include the smaller files:
Note that the !include directive is just an example; the syntax for including files will depend on your language or framework.
Pros and Cons
Pros:
- Improves organization and readability by splitting large files into smaller, focused modules.
- Makes collaboration easier by allowing team members to work on separate parts of the configuration.
Cons:
- Requires additional setup and configuration to manage multiple files.
- Can make it harder to understand the overall structure if not organized properly.
5. Use External Tools to Minify YAML Files
Minification is a technique commonly used to reduce the size of text-based files like JSON, CSS, and JavaScript. While less common, you can also minify YAML files to reduce their size.
How It Works
Minification tools remove unnecessary characters like whitespace, line breaks, and comments without affecting the functionality of the file. There are online tools and command-line utilities available that can minify YAML files.
Example
You can use a command-line tool like yq to minify a YAML file:
Or, you can use an online tool like YAML Minifier to minify your YAML file by pasting the content and then downloading the minified version.
Pros and Cons
Pros:
- Reduces file size by removing unnecessary characters.
- Can be easily automated as part of a build process or deployment pipeline.
Cons:
- Minified files can be harder to read and understand.
- Might not be suitable for all use cases or environments.
Combining these strategies with the ones we discussed earlier allows you to optimize your YAML files and keep them more manageable. Just remember to strike the right balance between file size and readability!

Conclusion
You can effectively reduce the size of your YAML files by using anchors and aliases to eliminate redundancy, adopting compact notation, and removing unnecessary comments and whitespace. Each method has pros and cons, so it's essential to consider the trade-offs when deciding which approach suits your situation.
Ultimately, a smaller YAML file improves performance and makes it easier to read, understand, and manage, so it's well worth the effort to optimize your files!
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