Properties โ YAML converter
Turn a flat application.properties into nested application.yml, or the reverse. Lists and nested objects are handled.
Properties or YAML for Spring Boot?
Spring Boot reads configuration from either application.properties or application.yml. Properties files are flat and repeat long prefixes on every line; YAML groups keys under a shared parent, which is easier to read once a config grows. Teams often start with one format and migrate to the other.
This converter does the mechanical work and flags problems it cannot resolve, such as a key that is both a value and a parent (a=1 and a.b=2), which has no valid YAML equivalent.
Frequently asked questions
Does Spring Boot treat properties and YAML the same?
Yes, both feed the same Environment. Lists are written app.hosts[0]=a in properties and as a dash list in YAML. Properties files win over YAML if both define a key.
How are lists converted?
Indexed keys like app.users[0].name become YAML lists of objects, and the reverse.
What YAML features are not supported?
The YAML to properties direction supports maps, lists and scalars, including quoted strings and comments. Anchors, multi-line blocks (| and >) and flow style ({a: 1}) are not supported.
Why does it quote some values?
Values containing ": " or starting with special characters are quoted so the YAML stays valid.