Question 1

Why are some values wrapped in quotes?

Accepted Answer

YAML decides a value's type from how it looks. Without quotes, “1.10” would be read as the number 1.1 and “true” as a boolean, so strings like these are quoted to stay strings. Plain text such as an image name stays unquoted.

Question 2

Will yes, no, on and off be read as booleans?

Accepted Answer

No. Strings that a YAML 1.1 parser would read as something else, like yes, no, on, off, y and n (booleans) or 2026-01-01 (a date), are written in quotes. PyYAML, Ruby and many CI tools still use YAML 1.1, so this keeps them as strings everywhere. YAML 1.2 parsers read the quoted values the same way.

Question 3

How are strings with line breaks written?

Accepted Answer

As a block scalar starting with |-, so each line of the string sits on its own line in the YAML instead of being squeezed into one line with 
 escapes. Any YAML parser reads it back as the same string.

Question 4

Do I need to convert at all?

Accepted Answer

YAML 1.2 was designed so that JSON is also valid YAML, and most YAML parsers will load a JSON file as it is. Converting is about people: YAML is shorter, easier to edit by hand and lets you add comments.

	JSON	YAML
Structure	Braces and brackets	Indentation
Quotes around strings	Always	Only when needed
Comments	Not allowed	Lines starting with #
Typical use	APIs, package.json, data exchange	Kubernetes, Docker Compose, GitHub Actions, Ansible

Convert JSON to YAML

How to convert JSON to YAML

JSON and YAML compared

Before you use the YAML