(Senior) Java Developer - Freelance

Job Description

We are looking for a highly experienced Senior Backend Engineer to join our client’s engineering team. The role focuses on building scalable, secure, and high-performance systems using Java and AWS cloud technologies. You will work in a cross-functional Agile environment, closely collaborating with architects, DevOps engineers, and business stakeholders.

This is a fully remote position.

Planned start: October
Salary ranges: up to 45EUR/h
Contract: B2B


Responsibilities

• Design, develop, and maintain backend systems using Java, Spring Boot, and AWS
• Build RESTful APIs, define and maintain OpenAPI specifications
• Package and deploy applications using Docker, manage deployments in AWS
• Develop and optimize data models using JPA/Hibernate and PostgreSQL
• Work with AWS services including IAM, Lambda, ECS, S3, AuroraDB, Cognito, API Gateway, ECR, CloudWatch
• Implement secure authentication/authorization using protocols such as OAuth2, OpenID Connect, JWT, SAML, and integrate with Azure AD
• Collaborate with Salesforce.com teams for API integration and auth flows
• Apply Domain-Driven Design (DDD) principles to model complex business domains
• Ensure best practices in code quality, security, and cloud architecture
• Contribute to Agile ceremonies, planning, code reviews, and architecture discussions

Requirements

• Technical Experience
• 8+ years of hands-on experience with Java, JUnit, Spring Boot, JPA/Hibernate, SQL, PostgreSQL, REST, OpenAPI
• 8+ years of experience working with Amazon Web Services, especially IAM, VPC, Cognito, API Gateway, Lambda, ECS, S3, ECR, AuroraDB, CloudWatch, AWS CLI
• Strong experience with containerization and deploying applications using Docker in AWS environments
• Good knowledge of Domain-Driven Design (DDD)
• Experience with authentication and authorization standards (AD, Azure AD, SAML, JWT, OAuth2, OpenID Connect)
• Experience with Salesforce.com (authentication, APIs, authorization)
• Familiarity with LLMs, AI agents, and Model Context Protocol (MCP)
• Solid understanding of data structures and application security principles
• Experience with GitHub, GitHub Actions, JFrog Artifactory
• Experience in Agile environments, ideally Scrum or SAFe
• Certifications
• AWS Cloud Practitioner certification required
• AWS Solutions Architect certification preferred
• Soft Skills
• Strong communication skills and a proactive, team-oriented mindset
• Fluent English (spoken and written); additional language skills are a plus

Benefits

In return, we offer:

• 100% remote, flexible work;
• work with an experienced team of developers and continuous development of your hard and soft skills;
• dev-friendly processes such as Continuous Integration, Continuous Delivery, Code Review and bug bashes;
• long-term collaboration on challenging products (FinTech, B2B software, E-commerce and more).

• We would like to know you better, so we will invite you for a meeting with our recruiter.
• Next, you'll be asked to solve the task or invited to an interview and pair programming with one of our iOS Developers.

Looking for a full-time job? Check out our Career Page and find out more about our open recruitment processes.

If you need any disability-related adaptation at any step of the recruitment process – simply let the recruiter know! We'd be happy to help.