Switching Between H2 and PostgreSQL in Spring Boot

October 28, 2025

This guide shows how to configure Spring Boot to switch easily between H2 for local testing and PostgreSQL for production.

1. Add Dependencies

In pom.xml:

<dependency>
  <groupId>org.springframework.boot</groupId>
  <artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>
<dependency>
  <groupId>com.h2database</groupId>
  <artifactId>h2</artifactId>
</dependency>
<dependency>
  <groupId>org.postgresql</groupId>
  <artifactId>postgresql</artifactId>
</dependency>

2. Default Profile

In application.properties:

spring.profiles.active=dev

Set dev as the default profile.

3. H2 Configuration (Dev)

In application-dev.properties:

spring.datasource.url=jdbc:h2:mem:devdb
spring.datasource.driver-class-name=org.h2.Driver
spring.datasource.username=sa
spring.datasource.password=
spring.jpa.hibernate.ddl-auto=create-drop

4. PostgreSQL Configuration (Prod)

In application-prod.properties:

spring.datasource.url=jdbc:postgresql://localhost:5432/mydb
spring.datasource.driver-class-name=org.postgresql.Driver
spring.datasource.username=postgres
spring.datasource.password=secret
spring.jpa.hibernate.ddl-auto=update

5. Switching Profiles

Run with H2 (dev):

mvn spring-boot:run -Dspring-boot.run.profiles=dev

Run with PostgreSQL (prod):

mvn spring-boot:run -Dspring-boot.run.profiles=prod

6. Benefit

Use H2 for fast in-memory testing.
Use PostgreSQL for real-world production.
Easy switching with profiles.