Senior Java Engineer - Flix Train Operations Management System

89-119 PLN/hour We are looking for a skilled Senior Java Engineer for service agreement collaboration (B2B contract) to cooperate with a team that focuses on automating and streamlining FlixTrain’s operational processes, creating internal tools that help teams manage a growing and increasingly modern fleet. The team works in a collaborative, pragmatic, low-bureaucracy way. Scope of services This engagement sits in a greenfield environment, where many systems are designed and built from scratch. Engineers are actively involved throughout the entire lifecycle: understanding operational challenges, contributing to architectural decisions, and ensuring high quality through solid testing practices. We value engineers who are curious about the business, eager to participate in discovery and problem framing, and comfortable navigating ambiguity. About the Engagement Collaborate with a self-organized, cross-functional distributed team responsible for a set of products, contributing directly to the success of the business Place our users at the center when developing solutions together with the team Contribute to the development process within an Agile environment Design new products from scratch and frequently deliver new versions of existing products, using continuous integration and automation Work with cutting-edge technologies and tools Contribute to technical decisions inside and across teams to improve technical excellence Share knowledge and provide technical guidance through code reviews and close collaboration Our tech stack: Java, Spring/Spring Boot, Kafka, MySQL (RDS), MongoDB (DocumentDB), AWS, Docker, GitLab CI, Kubernetes, Terraform, Datadog About You 7+ years of professional experience with Java Strong experience developing distributed systems using Spring Boot Experience with relational (MySQL, PostgreSQL, RDS) and NoSQL databases (MongoDB, DocumentDB) Experience with caching solutions such as Redis, ElastiСache Experience with event-driven architectures and messaging services like Kafka/SQS/SNS/RabbitMQ Hands-on experience with AWS services (e.g. RDS, S3, EC2) Experience with DevOps and infrastructure technologies, including Docker, Kubernetes, GitLab CI, Terraform, and Datadog Upper-intermediate level of English or higher Experience working within an Agile setup Nice to have: Data Engineering skills: ETL, Snowflake, etc. Experience working with distributed teams Collaboration model Contract type: Cooperation based on a service agreement (B2B/freelance contract), not an employment contract Working model: Independent contractor responsible for delivering agreed services and submitting invoices