Job Title: Senior Backend Developer (Java/Spring Boot) Company Name: BB Agency Job Details: €3k-€4k/moRemoteContract Job Url: https://hiring.cafe/viewjob/68gevwkgvi329p6w Job Description: Posted 5mo agoSenior Backend Developer (Java/Spring Boot)@ BB AgencyView All JobsWebsiteEurope or North America€3k-€4k/moRemoteContractResponsibilities:Implementing logic, Optimizing queries, Auditing changesRequirements Summary:5+ years backend Java experience with Spring Boot; knowledge of PostgreSQL, Kafka; English mandatory; Spanish a plus.Technical Tools Mentioned:Java, Spring Boot, Hibernate/JPA, PostgreSQL, Kafka, Amazon Aurora PostgreSQL, Amazon QLDB, SFTP/Files, SAP, Docker, AWS ECS/Fargate, Financial/Payroll Domain Quick summary 🌎 This is a fully remote position. 🇪🇺 Looking for people in Europe or LATAM. 🇬🇧 Professional English is a must. All company and client communication is in English. Spanish is a strong bonus (helps in understanding LATAM Payroll logic). 😎 5+ years of experience in backend engineering. You must be a Java 17+ expert with deep knowledge of Spring Boot, Hibernate/JPA, and PostgreSQL. Experience with Event-Driven Systems (Kafka) is required. 🔮 We are looking for a Core System Builder for a banking-grade HR & Payroll platform. You will be responsible for writing the complex business logic that powers Gross-to-Net calculations, Tax Deductions, and Bank Integrations.  💸 Salary: Gross (B2B) 3000€ ~ 4000€ / month. About us BB Agency is a partner for digital evolution, blending creativity and technology to drive meaningful growth. We collaborate with companies focused on real human needs, shaping brands, experiences, and products that impact millions daily. Founded in 2012 on Island Krk, Croatia, we've grown into a fully remote agency with a global team of 40+ members. We believe in learning by doing, open communication, and pushing boundaries to deliver our best work. Our clients range from tech SMEs to corporations and funded startups in SaaS, finance, healthcare, and more. We’ve partnered with names like AWS, Deloitte, BNP Paribas, ShipBob, Crisp, and CloudZero, among many others. Job description We are looking for a passionate Senior Backend Developer to join the foundational team for the HR & Payroll product we are building. You will be building the service-payroll-engine and service-hr-employee microservices. Your challenge is to implement complex Domain-Driven Design (DDD) patterns to model real-world labor laws and ensure that our payroll runs are 100% accurate, auditable, and performant. You will ensure that when we hit "Run Payroll," the system processes 100k rows in minutes, not hours, with penny-perfect precision. Your Responsibilities Core Logic Implementation: Write clean, testable, and efficient Java 17+ code using Spring Boot 3. You will implement calculation algorithms that handle retroactive salary adjustments and tax computations. Database Performance: Design and optimize complex SQL queries for Amazon Aurora PostgreSQL. You understand indexing strategies, transaction isolation levels, and how to avoid N+1 problems in Hibernate. Immutable Audit Trails: Integrate with Amazon QLDB to record every critical financial change (e.g., salary updates) ensuring data is tamper-proof. Event-Driven Development: Build asynchronous workflows using Kafka. Example: Listening for a CONTRACT_TERMINATED event to automatically trigger a "Severance Pay Calculation." System Integration: Build robust REST APIs to connect the system with external Banking Systems (SFTP/Files) and Legacy ERPs (SAP). Testing Culture: Maintain high test coverage. You believe that code without tests is technical debt. Code Review: Actively participate in PR reviews, ensuring your peers adhere to coding standards and security practices. Preferred experience 5+ years of backend development experience in a professional environment. Java Ecosystem: Deep understanding of the JVM, Memory Management, and Concurrency. Spring Boot Mastery: You are comfortable with Spring Data JPA, Spring Security, and building custom Starters if needed. AWS Familiarity: Experience running applications in Docker/Containers (AWS ECS/Fargate) and using other AWS managed services. Domain Experience: Background in Fintech, Payroll, Accounting, or complex B2B Enterprise software is highly preferred. Database Skills: Strong SQL knowledge. Experience with "Ledger" concepts or immutability is a plus. Problem Solver: You can take a vague business requirement and turn it into a working algorithm/microservice. Language: Fluent English is mandatory. Spanish is a significant advantage for reading "business requirements" (Payroll Laws) directly from the source. What to expect Flexibility - We have standard 40-hour work weeks. While our agency working hours are from 9 am to 7 pm CET, you’ll have the freedom to work flexible hours and maintain a healthy work-life balance. Just make sure the majority of your working hours fall within that time frame. Remote work & Tooling - We operate as a fully remote team. We utilize HubStaff for time tracking and work transparency. We value trust and output, and these tools help us streamline administrative overhead. Culture - We value collaboration, openness, a willingness to learn, lead, and a curious nature. Our approach encourages mistakes as long as we are willing to learn from them, fostering a culture where growth comes from understanding and overcoming challenges. Autonomy and responsibility – You’ll be trusted to get things done efficiently and effectively. Hiring process Pre-selection based on your application (We’ll review your experience, past projects, and skills). Introductory call with HR to get to know you better. Psychological evaluation. Interview with our Development Team leadership. Welcome to BB Agency.