(Senior) Java Developer - Freelance

Description
Netguru is a trusted partner in digital commerce. The company helps leading brands modernize B2B solutions, marketplaces, and retail ecosystems. Since 2008, it has empowered businesses with cutting-edge technology, AI-powered personalization, and world-class engineering and design teams. A certified B Corporation®, Netguru is trusted by major brands including IKEA, VW, OLX, Delivery Hero, Żabka, Wolt, Careem, and Vinted.

Position: Senior Backend Engineer

Contract: B2B – Remote (EU Only)

Rate: up to 30 EUR/hour + 20 paid vacation days

Language: English C1

Responsibilities
• Design and build scalable backend systems for processing large volumes of data
• Develop and maintain robust, high-performance APIs for data integration and access
• Build, optimize, and maintain ETL pipelines for data ingestion and transformation
• Process and manage large datasets in distributed environments
• Optimize system performance, latency, and throughput across backend services
• Improve database performance through indexing, schema design, and query optimization
• Collaborate with product managers, designers, and engineering teams to deliver scalable solutions
• Work closely with stakeholders to define and implement data-driven functionalities
• Ensure high standards of security, reliability, scalability, and maintainability
• Mentor and support other engineers as part of a senior-level engineering role
• Stay up to date with modern backend technologies, architecture patterns, and engineering best practices

Requirements
• Strong commercial experience with JVM-based languages such as Java, Scala, or Kotlin
• Solid experience with relational databases, including PostgreSQL and MySQL
• Experience working with NoSQL databases, preferably MongoDB
• Hands-on experience processing and managing large datasets
• Strong knowledge of scalable API design and backend architecture principles
• Experience designing distributed and high-performance systems
• Practical experience building ETL pipelines using standard data processing tools
• Experience with cloud platforms such as AWS, GCP, or Azure
• Strong understanding of performance optimization and low-latency systems
• Experience with database optimization, including indexing, schema design, and performance tuning
• Strong problem-solving and communication skills
• Senior-level mindset with the ability to mentor and support engineering teams
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English at C1 level

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Must be based in the European Union

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).

What will happen next?
• 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 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.