Configuration Properties and Profiles

Spring Boot reads configuration from application.properties/application.yml, environment variables (SPRING_DATASOURCE_URL), command-line args and more, in a defined precedence order. Bind related settings to a @ConfigurationProperties record with validation instead of scattering @Value. Profiles (application-dev.yml, spring.profiles.active=prod) switch settings per environment. Keep secrets in environment variables or a secret manager.

@ConfigurationProperties(prefix = "shop.payments")
@Validated
public record PaymentProperties(
        @NotBlank String apiKey,
        @NotNull URI baseUrl,
        @DurationUnit(ChronoUnit.SECONDS) Duration timeout) {}

@SpringBootApplication
@ConfigurationPropertiesScan
public class ShopApplication { /* ... */ }

# application.yml
shop:
  payments:
    base-url: https://api.stripe.com
    timeout: 5
    api-key: ${STRIPE_API_KEY}
---
spring:
  config:
    activate:
      on-profile: dev
shop:
  payments:
    base-url: http://localhost:12111

Common pitfalls

• Committing secrets in application.yml.
• Many @Value strings with typos that fail only at runtime.
• Profile-specific beans that make production behave differently from tests.

Key points

• Typed @ConfigurationProperties records
• Environment variables override files
• Profiles per environment

Further reading: Spring Boot: Externalized configuration