Recommended Case for Spring Properties | Generated by AI
Question: What case should we use in Spring properties?
Answer:
In Spring Boot (and Spring Framework in general), the recommended and most commonly used case for properties keys (in application.properties, application.yml, environment variables, etc.) in 2025–2026 is:
kebab-case (lowercase with hyphens)
# This is the Spring Boot team recommended style
server.port=8080
spring.datasource.url=jdbc:...
management.endpoints.web.exposure.include=health,info,prometheus
logging.level.org.springframework.web=DEBUG
spring.jpa.hibernate.ddl-auto=none
Official & community conventions in 2025–2026
| Style | Example | Status in Spring Boot | When you still see it |
|---|---|---|---|
| kebab-case | spring.datasource.url |
Recommended • Official default | Everywhere in docs, starters, examples |
| camelCase | spring.datasource.url |
Supported, but not preferred | Old code, people coming from Java-land |
| snake_case | spring_datasource_url |
Supported (mostly env vars) | Kubernetes ConfigMaps, some Helm charts |
| UPPER_CASE | SPRING_DATASOURCE_URL |
Supported (environment variables) | Docker, Kubernetes, CI/CD, 12-factor apps |
Quick rules most teams follow today
- Use kebab-case in
application.propertiesandapplication.yml - Use kebab-case when writing
@Value,@ConfigurationPropertiesprefixes - Use UPPERCASE_WITH_UNDERSCORES when reading from environment variables
// Recommended
@ConfigurationProperties(prefix = "feature-toggle")
public class FeatureToggleProperties { … }
// Still works, but less common now
@ConfigurationProperties(prefix = "featureToggle")
YAML is even stricter — kebab-case is basically mandatory for readability
spring:
datasource:
url: jdbc:postgresql://...
username: app_user
hikari:
maximum-pool-size: 15
management:
endpoints:
web:
exposure:
include: health,metrics,prometheus
Summary – what to use in new code (2026 best practice)
application.properties/application.yml→ kebab-case@ConfigurationPropertiesprefix → kebab-case- Environment variables → UPPER_SNAKE_CASE
- Java/Kotlin field names → camelCase or PascalCase
Almost every new Spring Boot project started in 2024–2026 follows kebab-case for properties.
References: