Jobs Java

About PredictSpring

PredictSpring is a market-leading company shaping the future of omni-channel retail and modern POS technology. We help global retail and lifestyle brands deliver seamless, scalable, and modern customer experiences across digital and in-store channels.

We are looking for a highly skilled and experienced Senior Java Full Stack Engineer to join our team and help build secure, scalable, and high-performance software solutions across our platform, products, and business operations.

In this role, you will work across backend development, frontend applications, cloud infrastructure, microservices, APIs, messaging systems, and CI/CD workflows. You will play a key role in building reliable enterprise-grade systems that support modern commerce, retail operations, and customer experience.

Responsibilities

As a Senior Java Full Stack Engineer, you will:

• Design, develop, and maintain scalable, secure, and high-performance backend services using Java and frameworks such as Spring Boot, Spring Cloud, Spring MVC, and Hibernate.
• Build and maintain application workflows, APIs, services, and platform features that support PredictSpring’s product and business operations.
• Develop and implement RESTful APIs and GraphQL services for seamless integration between frontend applications, backend systems, third-party platforms, and internal tools.
• Work with cloud-based infrastructure using AWS services such as EC2, S3, Lambda, and RDS, as well as Azure services such as Azure Functions, Azure SQL Database, and App Services.
• Build responsive and maintainable frontend features using modern JavaScript frameworks such as React.js, Angular, or Vue.js.
• Work with messaging and event-driven technologies such as Apache Kafka, RabbitMQ, ActiveMQ, and JMS.
• Utilize Docker and Kubernetes to containerize applications, manage microservices, streamline deployments, and support scalable production environments.
• Collaborate with cross-functional teams, including product, engineering, design, operations, and business stakeholders, to deliver high-quality software solutions.
• Troubleshoot, debug, monitor, and optimize applications for performance, scalability, reliability, and maintainability using tools such as JProfiler, New Relic, Prometheus, or similar platforms.
• Write clean, efficient, maintainable, and testable code following Java best practices, design patterns, and modern software engineering standards.
• Participate in code reviews, architecture discussions, technical planning, and continuous improvement of engineering practices.
• Implement and manage CI/CD pipelines using tools such as Jenkins, GitLab CI, CircleCI, AWS CodePipeline, and Azure DevOps.
• Ensure security, data protection, authentication, authorization, and secure communication across applications and services using tools and practices such as Spring Security, OAuth2, JWT, SSL/TLS, and OWASP guidelines.
• Stay current with the latest Java technologies, cloud platforms, DevOps practices, and industry trends, and apply relevant improvements to PredictSpring’s platform and operations.

Requirements

We are looking for someone with:

• Excellent communication skills, including fluent verbal English, with the ability to explain technical concepts clearly and collaborate effectively across distributed teams.
• Bachelor’s or Master’s degree in Computer Science, Software Engineering, Information Technology, or a related field.
• Proven experience as a Full Stack Engineer or Full Stack Developer, with a strong focus on Java 8 or later for backend development.
• Strong hands-on experience with Java frameworks such as Spring Boot, Spring Cloud, Spring MVC, Hibernate, and JPA.
• Strong experience designing, building, and maintaining scalable backend systems, APIs, microservices, and enterprise-grade applications.
• Experience with cloud technologies such as AWS and Azure, especially AWS EC2, AWS Lambda, AWS RDS, Azure Functions, Azure App Services, and Azure SQL Database.
• Extensive experience with frontend technologies such as JavaScript, React.js, Angular, or Vue.js.
• Expertise in containerization and orchestration technologies such as Docker and Kubernetes.
• Solid experience with SQL and NoSQL databases, including SQL Server, PostgreSQL, MySQL, MongoDB, Cassandra, Redis, or similar technologies.
• Experience with message brokers and event-driven architecture using tools such as Apache Kafka, RabbitMQ, or ActiveMQ.
• Strong working knowledge of RESTful API design and GraphQL for building reliable backend services.
• Experience with CI/CD tools such as Jenkins, GitLab CI, CircleCI, and cloud deployment services such as AWS CodePipeline and Azure DevOps.
• Knowledge of unit testing and integration testing frameworks such as JUnit, Mockito, Spring Test, or similar tools.
• Understanding of security best practices in the Java ecosystem, including Spring Security, OAuth2, JWT, SSL/TLS, and secure API design.
• Experience with version control systems such as Git and collaborative development workflows.
• Familiarity with agile development methodologies, sprint-based workflows, and collaborative engineering practices.
• Strong problem-solving and debugging skills, with the ability to resolve complex technical issues across both frontend and backend layers.

Preferred Qualifications

Nice to have:

• Experience with microservices architecture and distributed system design.
• Experience with tools and frameworks such as Spring Cloud, Netflix OSS, Hystrix, Eureka, or Docker Swarm.
• Familiarity with DevOps practices and infrastructure-as-code tools such as Terraform, Ansible, and CloudFormation.
• Experience with serverless computing using AWS Lambda or Azure Functions for scalable, event-driven applications.
• Experience with real-time data processing using tools such as Kafka Streams or message queue-based architectures.
• Familiarity with monitoring, observability, and logging tools such as Prometheus, Grafana, ELK Stack, Datadog, New Relic, or similar platforms.
• Experience with Agile/Scrum methodologies and project management tools such as JIRA.
• Experience supporting production systems, monitoring application health, and improving reliability over time.
• Experience working with high-traffic, scalable, customer-facing SaaS or enterprise platforms.
• Experience in retail, e-commerce, omni-channel commerce, or POS technology is a strong plus.

Why PredictSpring?

• Join a market-leading company shaping the future of omni-channel retail and modern POS.
• Work on high-impact engineering challenges at the intersection of commerce, cloud technology, and customer experience.
• Collaborate with a talented global team in a flexible remote work environment.
• Enjoy opportunities for growth, learning, and professional development.
• Contribute to products used by some of the world’s most recognized retail and lifestyle brands.
• Be part of an innovative, collaborative, and engineering-driven culture focused on building reliable, scalable, and measurable business value.

Requirements

• 4+ years of commercial software development experience, including 3+ years working with Java;
• Strong knowledge of Java, Spring Boot, Spring Framework, Maven, and RESTful services;
• Solid understanding of Object-Oriented Programming, software design principles, and backend architecture;
• Experience designing and developing microservice-based applications;
• Strong experience with relational and NoSQL databases (Redis, Cassandra, CouchDB or similar);
• Experience with message brokers such as RabbitMQ or Kafka;
• Experience implementing backend architecture best practices and scalable distributed systems;
• Experience designing and developing REST APIs;
• Solid understanding of client-server communication and distributed system concepts;
• Experience writing unit, integration, and automated tests;
• Experience with Git and modern development workflows;
• Experience working with CI/CD pipelines;
• Basic understanding of Linux environments;
• Ability to analyze complex technical problems and propose effective solutions;
• Upper-Intermediate or higher English level;
• Strong communication skills, ownership mindset, and ability to work effectively within a team.

Would Be a Plus

• Experience with Docker and containerized environments;
• Experience with Kubernetes and Helm;
• Experience working with YAML-based configurations;
• Experience with cloud platforms, particularly Microsoft Azure;
• Experience conducting code reviews and mentoring other developers;
• Understanding of common design patterns and software architecture principles;
• Experience using AI-powered development tools (GitHub Copilot, ChatGPT, Cursor, Claude, etc.) to improve development efficiency.

Responsibilities

• Design, develop, and maintain backend services and microservice-based solutions;
• Participate in architecture discussions and contribute to technical decision-making;
• Implement new functionality according to business and technical requirements;
• Analyze, troubleshoot, and resolve application issues and performance bottlenecks;
• Collaborate with QA, DevOps, Product, and other engineering teams to ensure reliable software delivery;
• Participate in code reviews and maintain high code quality standards;
• Communicate with customers and stakeholders regarding technical requirements, issues, and solution improvements;
• Estimate development efforts and participate in sprint planning activities;
• Create and maintain technical documentation when necessary;
• Contribute to continuous improvement of development processes, tools, and engineering practices;
• Mentor less experienced team members when needed.

On behalf of our client, we are looking for a Senior Java Developer.

About the Product

A tech startup building AI-driven tools that help companies and brands manage their marketing strategy, outbound activities, and programmatic campaigns. The environment is fast-paced, with minimal bureaucracy, direct ownership, and a strong focus on execution.

Responsibilities:

- Build high-performance, highly scalable backend services and APIs

- Design scalable and maintainable components

- Work directly with founders, product managers, and the tech team

- Contribute to architectural and technology decisions

- Work on AI integrations, data processing, and automation

Requirements:

- 5+ years of experience with Java

- Strong hands-on experience with Spring Boot

- Experience with PostgreSQL

- Experience designing and developing REST APIs

- Experience working with Azure cloud infrastructure

- Experience with Docker, Git, and GitHub

- Ability to work autonomously and solve problems independently

- Fluent English and/or Italian

- Availability during Italian business hours (CET/CEST)

Nice to Have:

- Experience with distributed systems or scalable architectures

- Experience with AI integrations / LLM APIs

- Experience in media or advertising domains

- Experience with data-oriented applications and architectures

- Startup or SaaS experience

- Familiarity with containers, cloud technologies, and DevOps practices

 Company offers:

- Long-term employment with possibilities for professional growth

- Fully remote work

- Reasonably flexible schedule

- 15 days of paid vacation

- Regular performance reviews

• Project Description:

  A next-generation cross-asset data management platform to provide globally consistent data and innovative tools to support business strategy for trade/sales clients, which is built on big data architecture, highly scalable, and cloud-ready. The platform enables industry-leading analytics, client reporting, regulatory compliance, surveillance, supervisory reporting, and data science solutions (data flame). The project tech stack: Java, Scala, Spring, SQL, Kafka, Hadoop.
  
  We are looking for a strong Senior Java Developer capable of being able to work within the team, being a mentor for team members, communicating with stakeholders, and being accountable for the outcomes of activities that are assigned.
  
  The role of the involves working with strong development teams (2 Senior Java Developers), the opportunity to work with big data, improving knowledge in this domain, and utilizing the resources of an international bank.

   

• Responsibilities:

  • Design and build frameworks for ingesting/modeling the complex Risk data
  • Develop Low latency caching to service Front office risk systems
  • Setup monitoring and management for services
  • Provide SME support for development of automated QA scripts
   

• Mandatory Skills Description:

  • Strong knowledge of Big Data technologies Hadoop Ecosystem (HDFS, Impala, HIVE, HBASE, etc.) and Apache Spark
  • At least 5 years of experience in software development, including professional backend software development experience;
  • Strong Knowledge of Java programming languages
  • Should be familiar with algorithms and design patterns
  • Familiarity with Linux environment, including scripting skills
  • Designing and building APIs (Java);
  • Java Server-side or Back-end development;
  • Core Java;
  • Java collections and multithreading;
  • Java Memory Management;
  • Database and SQL (writing stored procedures, designing table schemas).
  • Understanding of distributed systems.
  • Understanding of CI/CD workflow.
  
  • Ability to multi-task and work under pressure.
  • Ability to pick up new concepts and apply the knowledge.
  • Demonstrated problem-solving skills.
  • Enthusiastic and proactive approach with a willingness to learn.
  • The candidate is expected to be dynamic and flexible with a high energy level as this is a demanding and rapidly changing environment

Project Description:

A next-generation cross-asset data management platform to provide globally consistent data and innovative tools to support business strategy for trade/sales clients that is built on big data architecture, highly scalable, and cloud-ready. The platform enables industry-leading analytics, client reporting, regulatory compliance, surveillance, supervisory reporting, and data science solutions (data flame). The project tech stack: Apache Spark, Hive, Java, Scala, Spring, SQL, Kafka, Hadoop.

We are looking for a strong Senior Java Developer with Big Data experience (Hadoop, Spark) capable of build the design and establish the framework in order to expose and distribute the Risk data to wide variety of consumers including Finance, Front office Risk Systems, Trading Systems, Back office and Account systems. This should cover low latency access and Streaming, Push / Pull mechanisms depending on the type of consumers.

The role of the Senior Java Developer involves working with strong development teams (3 Senior Java Developers), the opportunity to work with big data improving knowledge in this domain utilizing the resources of an international bank.

Responsibilities:

• Design and build frameworks for ingesting/modeling the complex Risk data
• Develop Low latency caching to service Front office risk systems

Mandatory Skills Description:

• At least 5 years of experience in software development, including professional backend software development experience;
• Strong Knowledge of Java programming languages
• 1+ year of Big data development with extensive hands-on experience with Spark programming
• Strong knowledge of big data technologies like Hadoop (Hive) and Spark
• Should be familiar with algorithms and design patterns
• Understanding of distributed systems.
• Understanding of CI/CD workflow.
• Familiarity with Linux environment including scripting skills

Nice-to-Have Skills Description:

• Experience In-memory databases and caching
• Job Orchestration tools like Autosys or Airflow
• Financial background (where possible)

Languages:

English: B2 Upper Intermediate

Description of project:

For our customer in the E-Mobility Sector we are looking for a Senior backend Developer 

Tasks:

• Development and optimization of distributed microservices based on Java/Spring Boot
• Ensuring scalability, performance, and reliability in a cloud environment (AWS/Kubernetes)
• Building and further developing robust API and integration layers (REST, messaging, e.g., RabbitMQ)
• Implementation of best practices in software quality, including automated testing, code reviews, and CI/CD
• Consulting the operations team with stable and maintainable backend components

• Contributing to the development of digital products in the e-mobility sector, particularly for:

  • Charging infrastructure
  • Billing & monitoring
  • System integration (e.g., via OCPP)

   

Qualifications:

• Profound experience Java/Spring Boot Developer
• Experience building and operating distributed, scalable cloud-based microservices in the context of AWS and PaaS (ideally Kubernetes)
• Strong experience in Java enterprise development in a Spring / Spring Boot environment incl. Spring Integration and Spring Cloud Contract
• Experience with REST API and JMS (ideally RabbitMQ)
• Experience with Maven, GitLab CI, as well as MariaDB (MySQL), DocumentDB and Redis
• Software quality assurance incl. test automation with JUnit, Spring Boot Test as well as load/performance testing
• Agile Mindset, experience with Scrum and ideally SAFe
• Nice-to-have: EV charging/CPMS domain knowledge, Charge Point communication protocols like OCPP
• Fluent in English

GD Next is a European group of companies, specialising in KYC, Fraud prevention, financial messaging, and Open Banking solutions. We integrate innovative, modern technologies into the traditional financial sector to strengthen digital banking and enhance the customer experience. By combining proven, market-validated technologies with the expertise of our team and trusted partners across Europe, we deliver real and tangible value to our clients.

We are looking for a Junior Java Software Engineer to join our Open Finance project team. This is a great opportunity for aspiring developers who want to gain hands-on experience in financial technology and grow their expertise in Java development.
The role will also include participation in 24/7 project hotline support on a rotational basis for additional compensation.

Key Responsibilities:

• Develop and maintain backend services using Java and relevant frameworks.
• Assist in implementing solutions that align with OpenFinance and PSD2 standards.
• Support the integration of third-party financial institutions and payment service providers (ASPSPs).
• Work closely with senior developers and the customer project team to gather requirements, participate in design discussions, and contribute to the development process.
• Write and maintain clean, efficient, and well-documented code.
• Participate in code reviews to ensure adherence to best practices, security, and performance standards.
• Collaborate with front-end teams for seamless integration between backend and front-end components.
• Develop unit and integration tests to maintain code quality.

• Troubleshoot and debug issues in backend services.

   

Required Skills & Qualifications:

• Basic understanding of Java and hands-on experience in backend development.
• Familiarity with core Java concepts (OOP, multithreading, collections).
• Understanding of RESTful APIs and JSON.
• Knowledge of relational databases (PostgreSQL, MySQL, or similar).
• Experience using Git for version control.
• Basic understanding of web security concepts (OAuth 2.0, JWT, encryption techniques).
• Strong problem-solving skills and willingness to learn new technologies.
• Good communication and teamwork abilities.
• B2 English (Upper-intermediate or higher).

Desired Skills:

• Experience with Spring Framework (Spring Boot, Spring Security).
• Basic knowledge of cloud platforms (AWS, Azure) and containerization (Docker).
• Familiarity with CI/CD tools and deployment practices.
• Exposure to Agile methodologies (Scrum, Kanban).
• Interest in financial technology (FinTech) and willingness to learn OpenFinance and PSD2 regulations.

Additional Information:

• Candidates will have the opportunity to grow within the company and gain exposure to modern financial technologies.
• The role will include participation in 24/7 support on a rotational schedule (1 day on duty / 1 day off duty) for additional compensation.
• This is a great opportunity for junior developers to develop real-world experience in a fast-paced and innovative financial services environment.
• Location: Ukraine.
• The project language is Ukrainian.

The Mission

Wallee Group is a leader in advanced payment solutions, dedicated to providing robust, scalable, and secure systems across multiple domains. We enhance customer experiences through innovative payment and finance technology that empowers businesses to grow efficiently. With operations spanning several countries, we thrive on collaboration and agility, utilizing the Scrum framework to drive our international teams. At Wallee, we stay at the forefront of market trends, continuously innovating to deliver premier services to our global customers.

The Role

To achieve our mission of providing the market's best payment experience, Wallee is seeking experienced and versatile java software engineers for our Vilnius office. As disruptors in the payment space, we build industry-leading systems that demand the highest standards of security and reliability. We are constantly pushing our solutions into new territories, and we are looking for engineers who thrive in a fast-paced, agile environment to help us redefine the future of finance.

Tasks

Your Impact

• Architect Scalability: Design and develop highly resilient back-end systems using Java, ensuring our infrastructure handles global scale with ease.
• Feature Innovation: Own the end-to-end lifecycle of new features, from initial implementation to refined bug fixing and performance tuning.
• Collaborative Engineering: Work closely with product managers, UX designers, and QA to translate complex business needs into elegant technical solutions.
• Code Excellence: Drive quality through automated testing, rigorous code reviews, and the creation of clear, maintainable technical documentation.
• Stay Ahead: Continuously research and evaluate emerging technologies and methodologies to keep Wallee at the cutting edge of the fintech industry.

Requirements

What You Bring to the Table

• Technical Depth: Advanced proficiency in Java and core frameworks such as Spring, Spring Boot, and Hibernate.
• Systems Thinking: Proven experience building distributed systems and scalable, high-availability solutions.
• Data Mastery: Strong proficiency in SQL and experience managing complex data structures.
• Modern DevOps: Hands-on experience with CI/CD pipelines (Jenkins/GitLab CI) and containerization (Docker, AWS ECS).
• Agile Mindset: A degree in Computer Science (or equivalent experience) and a track record of thriving in fast-paced, Agile environments.

• Bonus Points: Experience with JavaScript, Apache Camel, or BPM engines.

   

  Benefits:

• You are part of an agile, young international team and shape our products sustainably with your ideas.
• You will play a decisive role in designing products in an omni channel payment start-up and work with leading companies in the financial industry on international projects.
• We offer flexible structures and flat hierarchies.
• Cooperation with motivated colleagues and numerous personal development opportunities.

The project involves the design, development, and maintenance of enterprise-level data processing and reporting solutions. It includes working with SAP Data Services for ETL workflows, SAP Business Objects for report development, and modern backend technologies such as Java and Spring Framework. The goal is to ensure accurate data transformation, integration, and presentation across systems in a scalable and reliable environment.

• Responsibilities:

  Install and configure SAP IPS/DS (BODS) and SAP BO tools.
  
  Design, build, and maintain ETL workflows using SAP Data Services and DBT.
  
  Develop and maintain Business Objects reports.
  
  Implement backend logic using Java 8+, Spring Framework, Hibernate, and Oracle DB.
  
  Write and optimize complex SQL queries.
  
  Ensure performance and data accuracy across transformation pipelines.
  
  Collaborate with cross-functional teams in an Agile environment.
  
  (Optional) Support frontend development using Angular/React/JSP if needed.
  
  Proactively contribute to problem-solving and system improvements.
  
  Communicate effectively with stakeholders and team members.

• Mandatory Skills:
  • dbt
  • SAP BO Data Services
  • SAP Business Objects (BO)
  • SAP Design Studio

• Mandatory Skills Description:

  Overall experience:
  A minimum of 4 years hands-on experience as a software developer in an enterprise organization working on complex custom developed applications
  Desired: working experience in agile software development
   
  SAP Data Services:
  Experience with instalation and setup of SAP IPS/DS (BODS)
  Design and development of ETL flows using SAP DS + Designer
   
  SAP Business Objects:
  Experience with instalation and setup of SAP BO
  Design and development of BO reports
   
  DBT:
  Developing, maintaining, and optimizing data transformation workflows using DBT, ensuring data accuracy
   

Project Duration: 3–4 months
Employment Type: Full-time
Compensation: Negotiable
English Level: B1+

We are looking for a Middle+/Senior Java Developer to join an ongoing project in the payments domain. The platform is already live and actively used in production, so the role focuses on enhancing existing functionality, implementing change requests, and supporting transaction processing workflows rather than building a system from scratch.

This position is ideal for an engineer who is comfortable working with mature codebases, quickly understanding existing business logic, and making reliable changes in production-critical systems.

Key Responsibilities

• Implement new features and change requests within an existing payment processing platform.
• Analyze, maintain, and enhance transaction-related business logic.
• Work with payment messaging and transaction processing flows.
• Investigate, troubleshoot, and resolve issues within a live production environment.
• Understand existing architecture and efficiently adapt current functionality to evolving business needs.
• Collaborate with the team to ensure stable and reliable delivery of new changes.

Requirements

• 3+ years of commercial backend development experience.
• Strong knowledge of Java and Spring Boot.
• Hands-on experience working with payment processing or financial transaction systems.
• Proven ability to navigate, understand, and modify complex existing codebases.
• Strong troubleshooting and debugging skills.

Mandatory Requirement

• Deep understanding and practical experience with the ISO 8583 protocol is essential.

What We Offer

• Full-time engagement on a live, business-critical payment platform.
• Opportunity to work directly with payment and transaction processing systems.
• Short-term project with immediate impact and ownership.
• Competitive compensation package with negotiable rates.

Our client is one of the leading companies on the market which provides Big Data, Data Integration, Data Preparation and Enterprise Application Integration software and services. Its products allow to build data integration process, migrate data safely, process big amount of data, cleanse data and check its quality.

Connector is a core element of the products, which allows to connect, extract data from a data source, transform data according to business needs and load data back to some storage. It is used in traditional software such as Studio for Data Integration as well as in the modern Cloud services.

Continuous emerging of new technologies and data repositories lead to demand growth of creating new connectors and adapting the existing ones.

For this reason, we are looking for a Java developer to join the team to address the demand and provide our client with the best quality service.
 

Requirements:

• Good knowledge of Java Core 8
• Some experience with SQL (knowledge of JDBC is a huge plus)
• Understanding and some experience in testing techniques (JUnit)
• English (both spoken and written) at least at Intermediate level that allows communicating with an international team on a daily basis

 Optional but desirable:

• Pet projects on Java Core
• Knowledge of JSON, XML
• Knowledge or experience with development and CI tools: Git/GitHub, Maven, Docker

Job responsibilities:

• Design and implement Talend Connectors 
• Unit and Integration testing
• Respond to feature requests, bug reports, performance issues and ad-hoc questions

Advantages:

• Smooth onboarding process
• Working under the supervision of a skilled teammate
• Chance to work with a great variety of technologies and DBs (both SQL and non-SQL such as Snowflake, PostgreSQL, Mongo, Cassandra, DynamoDB, Neo4j)
• Work collaboratively in a distributed international team (France, Germany, China)

About Flamingo

Flamingo is revolutionizing the Managed Service Provider (MSP) industry with an AI-driven, open-source platform for IT and security. Our goal is to empower MSPs with automation, optimization, and scalability tools to enhance their operations. 

Role Overview

As a Senior Back-end Engineer (Java) at Flamingo, you will design and develop scalable, high-performance back-end services and APIs using Java and Spring Boot. You will be responsible for implementing event-driven microservices, optimizing system performance, and ensuring high availability as we scale our platform. Your expertise in processing high-volume logs and integrating multiple data sources will be critical to building a robust and efficient system.

Key Responsibilities

• Design and develop scalable backend services and APIs using Java (Spring Boot).
• Architect and implement event-driven microservices with Kafka and RabbitMQ.
• Process and analyze high-volume logs efficiently to ensure scalability and real-time insights.
• Integrate and manage multiple data sources, including SQL, NoSQL, and streaming data.
• Optimize database performance using PostgreSQL, Redis, and Elasticsearch.
• Implement authentication and authorization mechanisms with OAuth, JWT, and Keycloak.
• Collaborate with front-end and DevOps teams to build a seamless and resilient system.
• Ensure code quality through automated testing, CI/CD pipelines, and best engineering practices.

Qualifications

Must-Have:

• 5+ years of experience in backend development with Java and Spring Boot.
• Experience in microservices architecture, including event-driven systems (Kafka, RabbitMQ).
• Strong knowledge of RESTful APIs, GraphQL, and WebSockets.
• Experience processing high-volume logs and working with log management tools (ELK stack, Loki, Fluentd, OpenTelemetry).
• Experience working with multiple data sources, including relational (PostgreSQL) and non-relational (Redis, Elasticsearch) databases
• Experience with containerization (Docker, Kubernetes) and cloud platforms (AWS/GCP).
• Understanding of security best practices in backend development.

Nice-to-Have:

• Experience with functional programming in Java or Scala.
• Familiarity with distributed tracing (e.g., Jaeger, Zipkin) for microservices.
• Knowledge of cloud-native architectures and serverless frameworks.
• Exposure to message queues and event sourcing.

Why Join Flamingo?

• High-impact role: As a back-end engineer, your contributions will directly shape Flamingo’s product and technology.
• Ownership & Equity: Competitive compensation, including significant equity in an early-stage, high-growth startup.
• Innovative Tech Stack: Work with cutting-edge open-source technologies in AI, automation, and security.
• Remote-first Culture: Flexibility to work from anywhere while collaborating with a top-tier team.
• Mission-Driven Company: Join a team passionate about disrupting the MSP industry and making enterprise-grade security and IT automation accessible to all.

About the Project

AI Interview Platform (client name undisclosed) — a leading technical interviewing platform used by fast-growing startups and large enterprises worldwide. It pairs experienced engineers with standardized interview frameworks to enable fair, high-signal, and scalable hiring for software engineers globally.

What You'll Do

• Conduct live technical interviews with software engineering candidates worldwide via the platform.
• Assess coding skills, problem-solving abilities, technical knowledge, and communication while creating a professional and inclusive candidate experience.
• Provide structured, objective feedback based on established evaluation criteria to reduce bias and improve hiring quality.
• Collaborate with the client’s team to test, refine, and improve interview content, processes, and platform features.

Must Have

• 4+ years of professional experience as a Software Engineer/Developer.
• Strong Java proficiency + working knowledge of frontend technologies (JavaScript, React, or similar).
• Solid understanding of algorithms, data structures, and software engineering fundamentals.
• Excellent English communication skills (spoken and written).
• Professional demeanor, ability to deliver objective assessments, and reliable setup (webcam, microphone, stable internet).

Nice to Have

• Prior experience conducting technical interviews (DS&A, system design).
• Mentoring, coaching, or technical leadership experience.
• Interest in talent assessment, interviewing best practices, or inclusive hiring.

Location: EU / Remote (Ukraine)

Type: Freelance full-time (first 3 months), with option to go part-time later.

N-iX is looking for an experienced Senior Java Engineer who goes beyond standard CRUD APIs and lives in the world of information retrieval.

Our customer is a Fortune 500 company. As a leading business-to-business organization, more than 3.2 million customers rely on its products in categories such as safety, material handling, and metalworking, along with services like inventory management and technical support. ​

In this role, you will act as the bridge between our core Java application architecture and our specialized search infrastructure. You will be responsible for the entire search lifecycle: from designing how data is ingested and indexed, to building the Java APIs that query that data, and crucially, tuning the relevancy algorithms that ensure our users find exactly what they are looking for, instantly. The ideal candidate has deep roots in the Apache Solr ecosystem but is also ready to embrace modern cloud-native search via AWS OpenSearch. Whether you are maintaining critical legacy Solr clusters or architecting new solutions on AWS, your goal is to make data findable, fast, and relevant.

Technology stack: Java/Spring Boot, Apache Solr (Legacy/Core), AWS OpenSearch (Modern/Growth), SQL DB, Kafka 

Responsibilities:

• Design, develop, and maintain high-performance backend Java services (primarily Spring Boot) that integrate with search engines.
• Build complex search features for the frontend, including faceted navigation (filtering), multi-tenant searching, real-time autocomplete/typeahead, and spell-checking suggestions.
• Utilize Java client libraries (such as Solr or AWS SDKs) to construct efficient, programmatic queries.
• Take ownership of the search schema design, deciding how complex data structures should be analyzed, tokenized, and stored for optimal retrieval.
• Build robust ETL pipelines in Java (potentially using Kafka or other messaging systems) to synchronize data from primary SQL databases into the search indices in near real-time.
• Configure analyzers, stemmers, and tokenizers to handle nuances in human language.
• Diagnose slow queries, analyze search logs, and optimize both Java application code and search engine configurations for low-latency performance.
• Maintain and optimize existing on-premise or cloud-hosted Apache Solr installations.
• Play a key role in designing hybrid strategies or migration paths from legacy Solr systems to managed AWS OpenSearch environments.

Requirements: 

• 5+ years of professional experience in backend software development using modern Java (Java 8+, Spring Boot ecosystem).
• Strong, demonstrable experience with Search Technologies. This means either:
  • Hands-on production experience configuring, managing, and developing against Apache Solr (understanding schema.xml, solrconfig.xml, Zookeeper integration).
  • OR deep foundational knowledge of Lucene-based search concepts (inverted indices, analysis chains, TF-IDF/BM25 scoring logic) with the ability to quickly apply that to Solr.
• Hands-on experience with AWS OpenSearch (or Elasticsearch) in a managed cloud environment.
• Experience with data modeling in relational databases (PostgreSQL, MySQL, Oracle).
• Strong understanding of RESTful API design principles.
• Preferred Qualifications:
  • Experience architecting zero-downtime migrations from self-hosted Solr to managed cloud search services.
  • Experience with event-driven architecture and streaming tools like Apache Kafka for real-time indexing.
  • Familiarity with containerization (Docker, Kubernetes) and CI/CD pipelines like Jenkins or GitLab CI.

We offer*:

• Flexible working format - remote, office-based or flexible
• A competitive salary and good compensation package
• Personalized career growth
• Professional development tools (mentorship program, tech talks and trainings, centers of excellence, and more)
• Active tech communities with regular knowledge sharing
• Education reimbursement
• Memorable anniversary presents
• Corporate events and team buildings
• Other location-specific benefits

*not applicable for freelancers

• Project Description:

  A next-generation cross-asset data management platform to provide globally consistent data and innovative tools to support business strategy for trade/sales clients, which is built on big data architecture, highly scalable, and cloud-ready. The platform enables industry-leading analytics, client reporting, regulatory compliance, surveillance, supervisory reporting, and data science solutions (data flame). The project tech stack: Java, Scala, Spring, SQL, Kafka, Hadoop.
  
  We are looking for a strong Senior Java Developer capable of being able to work within the team, being a mentor for team members, communicating with stakeholders, and being accountable for the outcomes of activities that are assigned.
  
  The role of the involves working with strong development teams (2 Senior Java Developers), the opportunity to work with big data, improving knowledge in this domain, and utilizing the resources of an international bank.

• Responsibilities:

  • Design and build frameworks for ingesting/modeling the complex Risk data
  • Develop Low latency caching to service Front office risk systems
  • Setup monitoring and management for services
  • Provide SME support for development of automated QA scripts

• Mandatory Skills Description:

  • Strong knowledge of Big Data technologies Hadoop Ecosystem (HDFS, Impala, HIVE, HBASE, etc.) and Apache Spark
  • At least 5 years of experience in software development, including professional backend software development experience;
  • Strong Knowledge of Java programming languages
  • Should be familiar with algorithms and design patterns
  • Familiarity with Linux environment, including scripting skills
  • Designing and building APIs (Java);
  • Java Server-side or Back-end development;
  • Core Java;
  • Java collections and multithreading;
  • Java Memory Management;
  • Database and SQL (writing stored procedures, designing table schemas).
  • Understanding of distributed systems.
  • Understanding of CI/CD workflow.
  
  • Ability to multi-task and work under pressure.
  • Ability to pick up new concepts and apply the knowledge.
  • Demonstrated problem-solving skills.
  • Enthusiastic and proactive approach with a willingness to learn.
  • The candidate is expected to be dynamic and flexible with a high energy level as this is a demanding and rapidly changing environment

• Nice-to-Have Skills Description:

  • Experience In-memory databases and caching
  • Job Orchestration tools like Autosys or Airflow
  • Apache Spark
  • Financial background (where possible)

• Languages:
  • English: C1 Advanced