Spring Spring is a framework for building Backend Application with JVM Language. Here is some sample project using Spring. Spring MVC REST API Simple Rest API Reactive REST API Annotation Based REST API + Databases Rest API + JPA (SQL) Reactive Rest API + MongoDB + Security Microservice Discovery service with Spring Cloud Netflix Eureka Config service(File System) with Spring Cloud Config Config service(Vault) with Spring Cloud Config Config service(Git Repository) with Spring Cloud Config API Gateaway with Spring Cloud Netflix Zuul Auth service Account service Firebase Push Notification service Cart Service Reactive Multipart File Reactive Video Service