What are Spring Boot Starters, and why do they exist?

Starters are curated dependency bundles — e.g. spring-boot-starter-web pulls in Spring MVC, an embedded Tomcat, and Jackson for JSON, all with versions that are known to work together. They exist to eliminate the manual, error-prone work of figuring out and aligning individual library versions for a common use case, letting you add one dependency instead of a dozen.