Middle Backend Developer (Kotlin/Java)

REMOTE RUSSIA / BELARUS

We are looking for an experienced Backend Developer. Initially, we offer a flexible start time – from 4 hours a day, allowing you to comfortably dive into the project, its architecture, processes, and team.

For effective team collaboration, it is important that your working hours fall within the 09:00 to 18:00 interval.

The project is actively developing with new services and development directions emerging, so we are aiming for long-term cooperation. As the workload increases and the developer successfully adapts, there is a possibility to transition to a full-time commitment.

If you are looking for a project where you can start with part-time employment and eventually become a full-fledged team member, this opportunity is ideal.

ABOUT THE PROJECT

We are developing a large enterprise platform with a White Label architecture, enabling the creation and scaling of corporate information systems for various clients.

The core idea of the platform is a unified backend, with each client receiving their own user interface featuring custom design, data display logic, and business processes. This approach allows a single backend to support multiple distinct client solutions, facilitating rapid product adaptation for new clients without significant server-side modifications.

The project is built on a modern microservice architecture. Core development is done in Kotlin using Spring Boot. The system also includes a Java monolith, which is gradually being decomposed and migrated to a microservice architecture.

The project ecosystem comprises specialized services responsible for data storage, dynamic form management, user action processing, list generation, and request routing. Inter-service communication is implemented via REST API.

A key feature of the platform is its dynamic interface management mechanism. The backend stores information about forms, fields, tables, buttons, element placement, and user actions. This allows new business processes to be created through the product's interface or directly via the REST API.

The project is in a stage of active development. The team regularly creates new microservices, expands existing APIs, optimizes system performance, develops internal platform services, and gradually migrates functionality from the monolith to a modern microservice architecture.

WHAT YOU WILL BE DOING

Developer responsibilities include:

• creating and supporting microservices in Kotlin
• developing existing services
• creating new REST APIs
• fixing bugs
• optimizing existing functionality
• optimizing database queries
• analyzing existing architecture
• working with PostgreSQL, MySQL, MongoDB, and Redis
• supporting the Java Monolith (a small portion of tasks)
• writing Unit and Integration tests
• developing new business functions
• working with the product beyond its development
• creating and developing internal platform services
• working with Docker and Docker Compose
• creating Grafana Dashboards when needed
• participating in the implementation of new authentication mechanisms
• integrations via OAuth 2.0
• actively participating in improving the product architecture (API Gateway pattern is used and already implemented)
• API documentation

TECHNOLOGY STACK

Core Stack:

• Kotlin
• Java
• Spring Boot (Spring Web, Data JPA, Mail, Security)
• Hibernate / JPA
• Lombok
• REST API
• WebSockets
• JSON
• PostgreSQL
• MongoDB
• Redis
• MySQL (Monolith)
• Docker/Docker Compose
• Git/GitLab

Technologies Used:

Microservices / API Gateway Pattern / JWT / Swagger / OpenAPI / Grafana / SSH/Bash/Shell / Liquibase / GitLab CI/CD / N8N (Low-code Automation Platform)

WHAT WE EXPECT FROM THE CANDIDATE

Mandatory:

• commercial experience in Kotlin development for at least 2 years
• commercial experience in Java development
• English proficiency sufficient for communication with an international team, discussing technical issues, and working in an international environment
• experience in microservice development
• understanding of ACID, SOLID, DRY, KISS principles
• strong knowledge of Spring Boot, Spring Security
• experience in REST API development
• experience working with PostgreSQL
• experience working with MongoDB
• understanding of Redis principles
• experience working with Docker
• experience writing Unit and Integration tests
• experience working with Git
• experience integrating with third-party APIs

Will be an advantage:

• experience implementing Social Login (via OAuth 2.0)
• experience working with Grafana (creating dashboards)
• experience configuring GitLab Pipelines (experience migrating to GitLab CI/CD)
• experience working with Flyway or Liquibase
• understanding of Hibernate (associations, cascading operations, entity lifecycle, N+1 problem in Hibernate)
• knowledge of design patterns (Decorator, Builder, Singleton)
• understanding of CAP theorem
• experience working with N8N
• experience working with SSH/bash/Shell
• experience supporting legacy Java applications
• experience migrating monolithic architecture to microservices
• experience developing custom Java annotations
• experience working with Loki/Prometheus/Tempo/Promtail

WHAT IS IMPORTANT FOR SUCCESSFUL WORK

We are looking for not just a developer, but an engineer who:

• is not afraid to work with limited documentation and can independently figure out how an internal application works
• can independently explore existing code
• is capable of quickly grasping a complex subject area
• can effectively collaborate with an international team
• is ready to propose technical solutions and ask questions
• can work with both modern microservices and, when necessary, legacy code