Senior Java Software Engineer

Solid Company sp. z o.o.; Kraków; On-site; PLN 240,000 - 360,000; Full time

Job summary

Solid Company sp. z o.o. in Kraków is seeking a Senior Java Developer to join a high-performance backend team building large-scale systems for travel and transportation.

You will design, implement, and optimize services and APIs powering mission-critical applications used by millions of users worldwide. The role requires 7+ years in backend Java development, strong expertise in Spring, Hibernate, RESTful services, and experience with cloud-native architectures.

Qualifications

• 7+ years of backend Java development experience.
• Strong knowledge of Java and Java EE technologies.
• Experience with Spring, Hibernate and RESTful APIs.
• Familiarity with cloud-native architectures.
• Ability to design scalable, reliable backend systems.

Responsibilities

• Design, develop, test, and debug complex backend services.
• Lead design and implementation of APIs powering travel platforms.
• Mentor developers and influence engineering best practices.
• Collaborate with Product and SRE to improve CI/CD and stability.
• Contribute to system architecture and code reviews.

Skills

Java

Spring

Hibernate

RESTful web services

OOP principles

XML

Relational databases

Linux-based development

CI/CD knowledge

Mentoring/team leadership

Tools

Maven

Gradle

Ant

Apache Camel

ServiceMix

Oracle SQL

Job description

We are looking for a Senior Java Developer with 7+ years of experience to join our high-performing team developing modern, large-scale backend systems for the travel and transportation industry.

If you have a strong background in Java development, cloud-native architecture, and enterprise-grade application design, this is your opportunity to take part in building the technology behind global travel experiences.

As a Senior Java Developer, you will lead a team to design, implement, and optimize backend services and APIs that power mission-critical systems used by millions of travelers worldwide. You'll play a key role in shaping system architecture, ensuring performance, reliability, and scalability - while mentoring developers and contributing to a culture of engineering excellence.

YOUR ROLE

• Design, develop, test, and debug complex software solutions
• Design and build prototype applications
• Research best practices, new tools, and technology.
• Work closely with technical staff to understand problems with software and resolve them
• Work closely with the Product team to understand business requirements
• Assist in the development of software technical documentation
• Support SRE in our effort to evolve CI/CD processes and stability
• 7-9 years of experience in backend software development.
• Strong proficiency in Java and related Java EE technologies.
• Deep knowledge of Spring, Hibernate, and RESTful web services.
• Solid grasp of OOP principles and design patterns.
• Experience working with XML and relational databases (Oracle, SQL).
• Familiarity with Linux-based development environments.
• Experience with build tools like Ant, Maven, or Gradle.
• Hands-on experience with Apache Camel and/or ServiceMix.
• Strong communication and team leadership skills.

NICE TO HAVE

• Experience working in Agile/Scrum development teams.
• Knowledge of JMS, JBoss, JMX, Drools.
• Understanding of TDD and experience with JUnit/unit testing.
• Java
• Spring
• Hibernate
• RESTful
• XML
• Apache
• Polski
• Angielski