How to convert application.properties to YAML

Pick Spring Boot or Quarkus; the two frameworks write profiles differently.
Paste your application.properties on the left. The YAML appears on the right as you type.
For Spring Boot, keep %profile keys as --- documents ticked to move each profile into its own YAML document.
Use Copy or Download to save the result as application.yaml.

Example

The properties server.port=8080, app.hosts[0]=a and app.hosts[1]=b become a nested server: block with port: 8080 and an app.hosts list with the itemsa and b. Indexed keys such as users[0].name become a list of objects. With Quarkus, %dev.quarkus.http.port=8081 is written under a top-level "%dev": key, which is how Quarkus reads profile-specific values from YAML.

Frequently asked questions

What happens when a key has a value and child keys?

Quarkus allows quarkus.http.cors=true next to quarkus.http.cors.origins=…. YAML cannot give a key both a value and children, so the value goes under the special ~ key, as the Quarkus docs show. Spring Boot has no such convention, so the tool warns you when it has to do this for Spring.

Why are some values quoted?

Spring Boot and Quarkus read YAML with SnakeYAML, which treats words such as on, off andyes as booleans and 0123 as an octal number. Those values are quoted so they stay exactly as they were in your properties file. Plain numbers and true/false are left unquoted.

Are comments, escapes and multi-line values kept?

Yes. Comments above a property move above its YAML key, and blank lines between groups are kept. Escapes such as\n, \t and é are decoded, and lines continued with a trailing backslash are joined, following the java.util.Properties rules. Your configuration never leaves your browser.