Java Backend Developer needed with Spring Boot and PSQL experience

We are designing an application that will link to different applications via OAuth to pull user-level data from different applications' APIs. We will then process this data and use it in different ways to serve the user in our own application. In our application, each user will be subscribed to a "plan", that will determine the business logic to be applied to that user's data. This posting is for designing and building the backend using Java, Spring and PSQL. The backend will need to serve the front-end and will need to handle: 1. Typical administrative requests such as user signup, preferences changes and linking external applications through OAuth. 2. An admin panel for managing different attributes of "plans", assigning users to plans etc. 3. Requests from the front-end that pertain to business logic 4. Pull data from the APIs, standardize it to a single data model while ensuring integrity of the data pulled by employing various checks (e.g. idempotency) **General Requirements** - Ability to design and deliver high throughput backend systems delivering a low latency for frontend using Java, preferably Spring Framework - Experience in designing middleware and backend layers and APIs - Knows how to use caches effectively to deliver very low latency responses to frontend requests - Ability to effectively translate business requirements into system design, code, data model design and relational database design. Can easily explain consequences of design choices - Uses a 'modular' approach to system design where each module is designed to operate as independently as possible - Familiar with concepts such as Optionals, Futures, lambdas, immutability and asynchronous design and processing - Experience with designing systems that pull data from external APIs and transform into form useful for internal usage - Experience in deploying systems that are resilient to failure - Ability to write appropriate unit and integration tests on a modular and system level. Experience with Data Mocking for testing a plus - Delivers high quality documentation including but not limited to comments in code, description of system design, API and modules - Open to frequent code reviews and functional demonstrations **Technical Requirements** - Experience with Java 8+, Spring and Spring Boot - Database design with Postgre SQL, including configuration and design on cloud-based linux servers - Familiar with message brokers such as Kafka and caching concepts - Experience with JPA such as Hibernate - Docker and Kubernetes experience a plus