Job Description

Job Overview

We are seeking an experienced Senior Java Developer / Senior Backend Engineer to join our client’s engineering team on a freelance B2B contract. In this role, you will design and build scalable, secure, and high-performance backend systems using Java, Spring Boot, and AWS cloud technologies.

You will collaborate with architects, DevOps engineers, and product stakeholders in an Agile development environment to deliver robust enterprise applications used by global customers.

This is a fully remote opportunity for a senior engineer who enjoys solving complex backend challenges and working with modern cloud-native architectures.

Start Date: October
Contract Type: B2B / Freelance
Rate: Up to €45 per hour
Location: Remote

Key Responsibilities

• Design, develop, and maintain high-performance backend services using Java and Spring Boot
• Build and maintain RESTful APIs and manage OpenAPI / Swagger specifications
• Develop cloud-native applications on AWS
• Containerize applications using Docker and support deployment pipelines
• Design and optimize database schemas using PostgreSQL, JPA, and Hibernate
• Integrate and manage AWS services such as:
  • IAM
  • Lambda
  • ECS
  • S3
  • AuroraDB
  • API Gateway
  • Cognito
  • ECR
  • CloudWatch
• Implement secure authentication and authorization using:
  • OAuth2
  • OpenID Connect
  • JWT
  • SAML
  • Azure AD integrations
• Collaborate with Salesforce teams for API integrations and authentication flows
• Apply Domain-Driven Design (DDD) principles for complex systems
• Participate in Agile ceremonies, architecture discussions, and code reviews
• Ensure best practices in scalability, security, and performance

Required Skills & Experience

• 5+ years of experience in Java backend development
• Strong expertise in Java, Spring Boot, and REST API development
• Experience with AWS cloud services and cloud architecture
• Hands-on experience with Docker and containerized deployments
• Strong knowledge of PostgreSQL, JPA, and Hibernate
• Experience implementing secure authentication protocols (OAuth2, JWT, OpenID Connect, SAML)
• Familiarity with CI/CD pipelines and DevOps workflows
• Experience working in Agile / Scrum teams
• Strong problem-solving and system design skills
• Excellent communication skills for remote collaboration

Nice to Have

• Experience with Salesforce integrations
• Knowledge of microservices architecture
• Experience with event-driven systems
• Familiarity with Azure AD authentication
• Background in enterprise SaaS platforms

Why Join?

• Fully remote freelance contract
• Work on modern cloud-native architecture
• Collaborate with an experienced international engineering team
• Opportunity to work on large-scale backend systems
• Competitive hourly rate up to €45

Keywords (SEO for Job Boards)

Senior Java Developer, Backend Engineer, Java Developer Remote, Spring Boot Developer, AWS Java Engineer, Microservices Java Developer, Freelance Java Developer, Remote Backend Engineer, REST API Developer, Cloud Java Engineer, PostgreSQL Developer, Docker AWS Engineer.