Jobs Java

We are looking for a Senior Backend Software Engineer to join the B2B Portals Team working with Raisin, a fintech company operating a digital savings and investment marketplace.

You will contribute to partner-facing platforms that allow banks, brokers, and financial advisors to offer Raisin deposit products to their customers. The team owns the full development lifecycle - from solution design and implementation to deployment and production support.

Responsibilities:

• Develop and maintain backend services using Java and Spring Boot;
• Deliver features from technical design to production rollout;
• Build APIs and integrations for banks and other B2B partners;
• Write unit, integration, and contract tests;
• Investigate production issues using logs, metrics, and traces;
• Conduct code reviews and contribute to engineering standards;
• Improve service performance, security, and reliability;
• Participate in the team’s on-call rotation;
• Mentor engineers and support knowledge sharing;
• Promote the effective and safe use of AI-assisted development tools;
• Collaborate with distributed teams and stakeholders across Europe and the US.

Requirements:

• 5+ years of commercial Java development experience;
• Strong knowledge of Java, Spring Boot, and Spring Data;
• Experience with AWS and cloud-based applications;
• Experience with REST APIs, distributed systems, and service integrations;
• Knowledge of relational databases, preferably MySQL;
• Experience with asynchronous messaging, particularly Amazon SQS;
• Strong testing skills with JUnit and Testcontainers;
• Experience with CI/CD, Docker, and Kubernetes;
• Ability to independently own and deliver backend features;
• Experience debugging production systems;
• Mentoring and code review experience;
• Fluent English.

Nice to have:

• Experience with fintech or banking integrations;
• Knowledge of Pact contract testing;
• Experience with Apache Kafka or Amazon MSK;
• Experience with event-driven systems;
• Experience with OpenTelemetry, Datadog, or Splunk;
• Familiarity with GitLab CI/CD, Harness, Amazon EKS, or Airflow;
• Experience with multi-tenant B2B platforms;
• Practical experience with AI-assisted development tools.

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

We are looking for an experienced Senior Full Stack Engineer with Java, Python and React experience to join our development team and contribute to the development of a customized AI-driven platform.

Our customer – integrated Shipping Services has set itself apart as an independent carrier with a fresh, unique approach. His strategy as a global niche carrier offers distinctive advantages to customers worldwide. We have created a smart, efficient network that ensures stable, reliable services; and we have made it our mission to focus on the needs of our customers, which stand at the heart of all our decisions. The main idea of our product operates in select trades, where it has a competitive advantage and where it can provide superior service. We maintain a flexible partnership approach with other major carriers, and our new line structure is a much-needed alternative to customers concerned about the current alliance-dominated market.

Responsibilities:

• Hand-On full stack development of innovative applications.
• Owning the entire development cycle, including design, architecture, development, and DevOps.
• Working in Extreme Programming methodology with remote pairing.

Requirements:

• BSc in Software Engineering or BS degree in Computer Science.
• 6+ years of experience in the following technologies: Java (must have), Spring.
• 2+ years of experience with Python (must have).
• 2+ years of experience in FE, mainly React (must have), and other modern JavaScript Framework/libraries.
• Experience with LLMs/AI/Prompt Engineering/MCP.
• Experience with Claude.code
• Experience with Data Analytics – big advantage.
• Experience in development in Kotlin – big advantage.
• Experience with Functional Programming and Java Streams.
• Experience with developing a reactive UI (Reactive JS).
• 2+ years of experience in TDD/BDD development in the following frameworks: Junit, Jasmin, Mockito, Protractor/Selenium
• 3+ years of experience in micro-services-based architecture and tools (Spring Boot/Cloud)
• Experience in DevOps development and Jenkins.
• Experience in designing, developing, and deploying cloud/hybrid-based solutions.
• Experience in developing and deploying in Container based environments (Kubernetes, Cloud foundry).
• Familiarity with the following design concepts: micro-services, service discovery, circuit breaker.
• Self-starter with the ability to appropriately priorities and plan complex work in a rapidly changing environment.
• Versatility and capability to switch easily between different tasks and technologies.
• Experience in assessing a broad range of information solutions and products.
• Strong critical thinker with problem solving aptitude.
• Good English - verbal and written.

TJHelpers is committed to developing strong engineering teams through mentorship, real project experience, and our “Helpers as a Service” model. We provide structured growth, hands-on practice, and a supportive environment where engineers can evolve quickly and meaningfully.

We are looking for a Senior Java Developer (Technical Consultant) to join our team and help build scalable, high-performance backend systems for fintech, AI, telecommunications, healthcare, and other high-load domains.

This role combines hands-on backend development with participation in architecture design, technical planning, and a consulting-driven approach to building reliable, scalable, and maintainable systems.

Responsibilities

• Design and develop scalable backend services and microservices using Java 17/21, Spring Boot, and Spring Cloud 
• Participate in architecture design, technical planning, and engineering decision-making 
• Build event-driven systems using Kafka or RabbitMQ and develop REST or GraphQL integrations 
• Improve system performance, scalability, reliability, and maintainability 
• Optimize application performance, database interactions, and backend processing flows 
• Collaborate closely with DevOps, QA, product, and engineering teams 
• Participate in code reviews and contribute to engineering best practices 
• Diagnose and resolve issues in production environments 
• Participate in technical discussions with clients and stakeholders when needed 
• Provide technical guidance, architectural recommendations, and mentorship 

Requirements

• Strong commercial experience with Java and Spring Boot/Spring Cloud 
• Strong experience designing and building microservices, REST APIs, and distributed systems 
• Strong understanding of software architecture principles and integration patterns 
• Experience with PostgreSQL or MySQL and Hibernate/JPA 
• Experience with Kafka, RabbitMQ, or other messaging systems 
• Experience optimizing application performance, scalability, and database interactions 
• Experience with Docker and CI/CD pipelines 
• Experience with at least one cloud platform such as AWS, GCP, or Azure 
• Strong debugging, troubleshooting, and problem-solving skills 
• Ownership mindset and responsibility for technical solutions and delivery quality 
• Ability to communicate technical decisions clearly to both technical and non-technical stakeholders 

Nice to Have

• Experience with Redis, Elasticsearch, or GraphQL 
• Knowledge of Kubernetes or Terraform 
• Experience working with high-load systems, caching, and observability tools such as Prometheus, Grafana, or ELK 
• Familiarity with event-driven architecture and asynchronous communication patterns 
• Experience participating in technical consulting, solution design, or system modernization initiatives  

What We Offer

• Work on real-world projects in fintech, AI, telecommunications, healthcare, and other modern domains 
• Opportunity to influence architecture and technical decisions 
• Clear growth path toward Tech Lead or Architect roles 
• Open engineering culture with transparent processes and strong technical collaboration 
• Flexible schedule and fully remote work opportunities

TJHelpers is committed to developing strong engineering teams through mentorship, real project experience, and our “Helpers as a Service” model. We provide structured growth, hands-on practice, and a supportive environment where engineers can evolve quickly and meaningfully.

We are looking for a Java Developer to join our backend team in our Odesa office, located in the Primorskyi District.

You will contribute to building scalable, high-performance, and reliable microservices for modern products across fintech, AI, telecom, healthcare, and other high-load domains.

Responsibilities

• Design, develop, and maintain scalable backend microservices and APIs.
• Write clean, efficient, and well-tested code using Java (17/21) and Spring Boot.
• Work with event-driven architectures using tools like Kafka or RabbitMQ.
• Integrate with internal and external REST/GraphQL services.
• Collaborate closely with DevOps, QA, and product teams to deliver high-quality features.
• Participate in code reviews and help establish engineering best practices.
• Optimize backend systems for performance, reliability, and cost efficiency.

• Investigate and resolve production issues, contributing to CI/CD and observability improvements.

   

Requirements

• Strong knowledge of Java and hands-on experience with Spring Boot / Spring Cloud.
• Experience building REST APIs, microservices, and integrations.
• Solid understanding of relational databases (PostgreSQL/MySQL) and ORM frameworks (Hibernate/JPA).
• Familiarity with Docker, containerization, and CI/CD pipelines.
• Knowledge of software architecture principles: microservices, event-driven systems, clean architecture.
• Experience with Git, unit testing (JUnit), and debugging/profiling tools.

• Good problem-solving skills and ability to work in a fast-paced environment.

   

Nice to Have

• Experience with cloud platforms (AWS, GCP, Azure).
• Knowledge of Kafka, Redis, Elasticsearch, or GraphQL.
• Experience with Kubernetes, Helm, or Terraform.
• Understanding of caching strategies, messaging patterns, and high-load system design.
• Experience with performance tuning, monitoring (Prometheus/Grafana), and observability tools (ELK).

• Familiarity with ML/AI integrations or data pipelines.

   

We Offer

• Real-world projects in fintech, AI, telecom, and automation industries.
• Mentorship from senior engineers, tech leads, and architects.
• Personal development plan and a clear path toward Senior Java Engineer or Backend Architect roles.
• Access to internal workshops, best practices, and structured feedback.
• A collaborative engineering culture focused on transparency and continuous improvement.
• Long-term projects, flexible schedule, and a remote-friendly work environment.

TJHelpers is committed to developing strong engineering teams through mentorship, real project experience, and our “Helpers as a Service” model. We provide structured growth, hands-on practice, and a supportive environment where engineers can evolve quickly and meaningfully.

We are looking for a Java Developer to join our backend team and contribute to building scalable, high-performance, and reliable microservices for modern products across fintech, AI, telecom, healthcare, and other high-load domains.

Responsibilities

• Design, develop, and maintain scalable backend microservices and APIs.
• Write clean, efficient, and well-tested code using Java (17/21) and Spring Boot.
• Work with event-driven architectures using tools like Kafka or RabbitMQ.
• Integrate with internal and external REST/GraphQL services.
• Collaborate closely with DevOps, QA, and product teams to deliver high-quality features.
• Participate in code reviews and help establish engineering best practices.
• Optimize backend systems for performance, reliability, and cost efficiency.

• Investigate and resolve production issues, contributing to CI/CD and observability improvements.

   

Requirements

• Strong knowledge of Java and hands-on experience with Spring Boot / Spring Cloud.
• Experience building REST APIs, microservices, and integrations.
• Solid understanding of relational databases (PostgreSQL/MySQL) and ORM frameworks (Hibernate/JPA).
• Familiarity with Docker, containerization, and CI/CD pipelines.
• Knowledge of software architecture principles: microservices, event-driven systems, clean architecture.
• Experience with Git, unit testing (JUnit), and debugging/profiling tools.

• Good problem-solving skills and ability to work in a fast-paced environment.

   

Nice to Have

• Experience with cloud platforms (AWS, GCP, Azure).
• Knowledge of Kafka, Redis, Elasticsearch, or GraphQL.
• Experience with Kubernetes, Helm, or Terraform.
• Understanding of caching strategies, messaging patterns, and high-load system design.
• Experience with performance tuning, monitoring (Prometheus/Grafana), and observability tools (ELK).

• Familiarity with ML/AI integrations or data pipelines.

   

We Offer

• Real-world projects in fintech, AI, telecom, and automation industries.
• Mentorship from senior engineers, tech leads, and architects.
• Personal development plan and a clear path toward Senior Java Engineer or Backend Architect roles.
• Access to internal workshops, best practices, and structured feedback.
• A collaborative engineering culture focused on transparency and continuous improvement.
• Long-term projects, flexible schedule, and a remote-friendly work environment.

Job Description

• Possess 8–12 years of progressive, hands-on experience in software engineering, with strong expertise in designing and developing enterprise-grade Java applications and services.
• Demonstrated experience acting as a technical lead, driving technical decisions, coordinating implementation activities, and supporting engineering teams.
• This role operates within a dynamic and collaborative environment, requiring a professional approach to remote work while fostering strong team communication and engagement.

Required Skills:

• Demonstrated expert-level proficiency in Java, including strong knowledge of core Java, multithreading, concurrency, collections, JVM concepts, and modern language features.
• Extensive hands-on experience with Spring Framework and Spring Boot for developing scalable enterprise applications, backend services, and APIs.
• Strong understanding of software architecture and design principles, including microservices, distributed systems, RESTful services, design patterns, and scalable application design.
• Proven experience designing, developing, and integrating REST APIs and enterprise backend services.
• Extensive experience operating within public cloud environments, particularly Azure, for deploying and managing enterprise applications.
• Strong hands-on experience with containerization and orchestration technologies, including Docker, Kubernetes, and Helm.
• Deep understanding and practical application of DevOps practices, including CI/CD pipelines, automated builds, deployment automation, and infrastructure-related development practices.
• Proficiency in C#, with practical experience developing, maintaining, and troubleshooting .NET-based applications and services
• Expertise in designing, optimizing, and working with relational databases, such as PostgreSQL, MS SQL Server, or similar technologies, including strong knowledge of SQL and database performance.
• Experience with automated testing approaches, including unit, integration, and service-level testing, and integrating automated tests into CI/CD pipelines.
• Strong understanding of secure software development principles, authentication and authorization mechanisms, data protection, and application security.
• Exceptional written and verbal communication skills, with a proven ability to effectively interact with engineering teams, product stakeholders, external customers, and strategic partners.
• An in-depth understanding and practical experience within the healthcare industry, including relevant compliance, security, and software quality considerations, will be a plus.

Job Responsibilities

• Lead the technical design and development of robust, scalable, secure, and maintainable Java-based enterprise applications and services.
• Drive the implementation of advanced Java and Spring Boot solutions, ensuring adherence to engineering best practices and high-quality coding standards.
• Provide technical leadership to the development team, supporting engineers in solving complex technical challenges and making effective implementation decisions.
• Lead technical design discussions for new features, services, integrations, and system enhancements.
• Oversee the planning, technical decomposition, and delivery of complex software features within an Agile development lifecycle, ensuring timely and high-quality outcomes.
• Define and promote appropriate software design patterns and engineering principles to ensure system scalability, reliability, performance, and maintainability.
• Design and implement backend services and APIs and ensure effective integration with other applications, platforms, and external systems.
• Investigate complex technical problems and propose effective solutions related to application architecture, integrations, performance, reliability, security, and data management.
• Collaborate closely with product management, QA, DevOps, and other engineering teams to translate business and system requirements into technical solutions.
• Conduct detailed code reviews and ensure compliance with established coding standards, architectural guidelines, security requirements, and engineering best practices.
• Drive initiatives to optimize application performance, security, maintainability, and operational reliability across the platform.
• Ensure comprehensive documentation of technical designs, APIs, key implementation decisions, deployment considerations, and operational procedures.
• Be accountable for the technical quality and successful delivery of assigned modules and features, proactively identifying technical risks and driving their resolution.

Department/Project Description

The client is a global leader in the medical technology sector, specializing in advanced diagnostic and surgical systems that combine precision mechanics, real-time control, and high-fidelity imaging. Operating within a strictly regulated, quality-driven environment, the organization is recognized for engineering devices where reliability, safety, and traceability are paramount. Its products support critical clinical workflows, and its engineering culture places strong emphasis on rigorous verification and risk-aware design.

The project centers on the development of a next-generation device platform built around a modern, high-performance microcontroller architecture. Key initiatives include upgrading the underlying operating system, modernizing the platform's internal communication from a legacy bus to a higher-bandwidth Ethernet-based transport for demanding data and imaging needs, and strengthening the hardware abstraction layer to improve portability and maintainability.

Project Description:

You will join a Regulatory Reporting Platform within a large US investment bank. The platform is responsible for collecting, processing, and transforming large volumes of data from multiple internal systems to produce regulatory reports for 240 jurisdictions worldwide. In total, the platform supports around 10,000 reports across a wide range of regulatory, compliance, financial, and risk reporting areas.
This is a large-scale, business-critical data platform operating in a highly regulated environment, where data accuracy, quality, traceability, and timely delivery are essential. The team works on building and enhancing data pipelines, implementing reporting logic, ensuring data validation and reconciliation, and supporting the generation of complex regulatory outputs.
The project is delivered by a global distributed team with colleagues located in Ukraine, Poland, and the US, offering close collaboration with engineers, analysts, and business stakeholders across multiple regions.

Responsibilities:

- Design, develop, and maintain solutions for a large-scale Regulatory Reporting Platform
- Build and enhance data processing pipelines using Java and Apache Spark
- Implement scalable logic for data ingestion, transformation, aggregation, and enrichment from multiple internal data sources
- Develop and optimize batch processing jobs to support the generation of regulatory reports across multiple jurisdictions
- Ensure high standards of data quality, validation, reconciliation, and consistency throughout the reporting lifecycle
- Translate business and regulatory requirements into robust technical solutions
- Collaborate with business analysts, QA engineers, and cross-functional teams to deliver reporting functionality
- Investigate and resolve data and application issues in development, test, and production environments
- Improve application performance, scalability, and reliability for high-volume data processing workloads
- Contribute to the design and implementation of reusable components and engineering best practices
- Participate in code reviews, testing, and release activities to ensure high-quality deliverables
- Work closely with distributed teams across Ukraine, Poland, and the US in an agile delivery model
- Support continuous improvement of the platform, including monitoring, troubleshooting, and operational stability

Mandatory Skills:

- 6+ years of commercial experience with Java
- Experience in designing and developing scalable, high-performance backend applications
- Good knowledge of SQL and working with large datasets from multiple data sources
- Strong problem-solving skills and ability to work effectively in a global distributed team

Nice-to-Have Skills Description:

- Spark and Hadoop knowledge
- Experience in financial services, investment banking, or regulatory reporting projects
- Familiarity with data quality, reconciliation, and control frameworks
- Experience working with large-scale enterprise data platforms
- Knowledge of cloud environments and modern data platform architectures
- Understanding of CI/CD practices and automated deployment pipelines
- Experience working in Agile / Scrum teams within a distributed global setup

Recruitment process:

1. CV Review — the project team reviews your experience and its relevance to the position.
2. Coderbyte Test — an online coding assessment.
3. Technical Interview — a technical discussion with our interviewer.
4. Project Management Interview (PMI) — a discussion about your experience, communication, and project fit.
5. Karat Interview — the first technical interview with the client.
6. Client Interview — the final interview with the client’s project team.

Location: Poland 

🌍Who we are:

Adaptiq is a technology hub specializing in building, scaling, and supporting R&D teams for high-end, fast-growing product companies in a wide range of industries.

🧩About the Product:

Our client is a major online gaming operator building a next-generation transactional platform for user account management. This is a greenfield project designed to operate in a highly regulated, high-volume environment and support millions of concurrent users. The platform will process financial transactions in real time and must ensure high availability, sub-second performance, data integrity, security, and full auditability. One of the key engineering challenges is maintaining reliability and performance during extreme traffic spikes and peak events. 

🌟 About the Role:

As a Senior Java Engineer, you will design and build the core backend services of the PAM platform from the ground up. You will own features end-to-end, from technical design and implementation to automated testing, production monitoring, and release. You will work closely with Principal Engineers on architecture and technical decisions, contribute to RFCs, and deliver production-ready code. You will have a high level of autonomy and real influence over the platform’s design, while taking strong ownership of reliability, performance, and correctness in a critical financial system.

📈 Key Responsibilities:

• Design and build backend services in Java 17+ (Spring Boot or similar) for wallet transactions, ledger entries, payment orchestration, bonus mechanics, and account state management.
• Develop REST APIs and event-driven integrations using Kafka or similar technologies for player-facing frontends, operations tooling, and external partners.
• Ensure correctness and reliability through idempotent operations, clear transaction boundaries, explicit failure handling, and strong unit, integration, and contract testing.
• Embed regulatory requirements into the platform, including KYC/AML checks, responsible gaming controls, and audit trails.
• Ensure production readiness with metrics, structured logging, distributed tracing, alerting, and participation in on-call rotations.
• Contribute to technical design and RFCs, participate in code reviews, and mentor other engineers.
• Use AI-assisted development tools as part of the daily workflow, following platform standards for context and prompts.
• Support live migration from the existing third-party platform, including parity testing, data validation, and cutover coordination.

💻 Required Competence and Skills:

• 5+ years of backend engineering experience with strong hands-on expertise in Java 17+ and a modern framework such as Spring Boot.
• Proven experience building and operating high-integrity transactional systems such as payments, wallets, billing, banking, e-commerce, or gaming.
• Strong relational database expertise (PostgreSQL or equivalent), including schema design, ACID transactions, locking, and performance tuning.
• Experience with event-driven architecture and messaging (Kafka, RabbitMQ, or similar), including idempotency and retry mechanisms.
• Strong testing practices, including automated unit, integration, and contract tests as part of the standard development process.
• Hands-on production experience with containers, CI/CD pipelines, monitoring/telemetry, and production incident troubleshooting.
• Solid understanding of multi-threading, system architecture, and fault-tolerant design patterns.
• Good written and spoken English, with experience working effectively in distributed.

➕ Nice to Have:

• Experience in iGaming, sports betting, fintech, or another regulated, high-transaction-volume domain.
• Exposure to Kubernetes and AWS, including VPC, IAM, EKS, and auto-scaling.
• Experience with compliance-driven development, including KYC/AML, responsible gaming, and audit requirements.
• Experience with AI coding assistants and agentic development workflows.
• Polish and/or Spanish language skills.

🚀 Why Us:

- We provide 20 days of vacation leave per calendar year (plus official national holidays of a country you are based in).

- We provide full accounting and legal support in all countries we operate.

- We utilize a fully remote work model with a powerful workstation and co-working space in case you need it.

We are building the platform, which supports various information gathering and processing across the bank. The PMC application, Price Master Central (PMC) is a global reference data management application - responsible for sourcing securities/Pricing data from market vendors and internal sources and providing it to downstream clients after applying client specific rules.

• Responsibilities:

  - Manage a team
  - Intensive communication with project stakeholders and other teams
  - Evaluate and adopt new development tools, libraries and approaches to improve delivery quality
  - Continuous quality improvement (code reviews, fixing Sonar issues, unit/integration/E2E test coverage)
  - Integrate our components with different internal and external client's systems
  - Configure, monitor, and troubleshoot Application servers
  - Monitor applications, processes, scheduled jobs, collect different types of logs and metrics
  - Setup and improve CI/CD
  - Automate routine with scripting languages
  - Write all types of tests: unit, integration, end-to-end
  - Design distributed applications

• Mandatory Skills Description:

  - Technically strong energetic individual, who can bring innovation to the group
  - Team lead experience from 3 years, IT experience from 7 years
  - Java (Core, JDBC, MT, Collections, I/O), Spring Boot
  - SQL.PL-SQL on Oracle DB
  - Container platform based on Kubernetes
  - REST web services, Kafka, Redis
  - Unix Commands and shell scripting.
  - Familiarity with standard data structures and algorithms.
  - Experience using the following tools - JIRA, Harness/uDeploy, SonarQube, TeamCity, Artifactory, Git (GHE & Bitbucket)
  - Logical thinking, strong analytical and problem-solving skills; innovate and solutions oriented
  - Effective time management skills to manage multiple priorities with flexibility on time zones and timelines
  - Excellent verbal and written communication skills
  - Bachelor's degree in computer science or equivalent work experience

About the role

Are you ready to take your Java expertise to the next level? Join our team to work with a highly scalable, highly available, real-time advertising platform that serves millions of users worldwide and handles massive real-time data at scale. We are hiring a Software Engineer to be a vital part of this mission. If you bring extensive experience building complex systems, love great technology at scale, jumping in, and figuring things out in any system, this role is for you! Working in a modern, cloud-native environment, you’ll collaborate with a team of top engineers to develop low-latency, distributed systems capable of handling millions of QPS. This is an opportunity to combine innovation, performance engineering, and large-scale impact - while shaping the future of digital entertainment technology.
 

About the project

Our client is a leading streaming service based in the United States. With millions of users worldwide, its devices provide easy access to free TV, live news, sports, movies, etc. The client has an advertising business and also licenses its hardware and software to other companies.
 

Who are we looking for?

Skills & Experience

• 4+ years of experience building large scale and low latency distributed systems
• 5+ years of Java backend development experience;
• Solid understanding of algorithms, data structures, performance optimization techniques, object-oriented programming, multi-threading, and real-time programming 
• Experience with distributed caching, SQL/NO SQL, and other databases is a plus 
• Experience with Big Data and cloud services such as AWS/GCP is a plus
• Experience in advertising domain a big plus 
• Self-motivated individual with a high level of accountability and ownership
• Critical thinking and practical decision making
• Can do, results-oriented mindset
• Software development best practices: test-driven development, automated testing;
• Knowledge of distributed systems architecture and service oriented systems;

• English: B2+

   

Nice to have

• Familiarity with machine learning frameworks (e.g., TensorFlow, PyTorch) and working with large language models (LLMs)

   

Responsibilities

• Develop and maintain complex backend services
• Collaborate with cross-functional teams (Product, Design, QA) to deliver high-quality features;
• Write unit, integration, and end-to-end tests;
• Maintain and extend existing services to meet new requirements;
• Participate in code reviews and contribute to technical discussions;
• Help maintain technical documentation;
• Assist in improving CI/CD pipelines;
• Contribute to best practices within the development team.

360 Synergy is a B2B SaaS platform for the US market  - a Gamified HR & Culture Platform. We help service companies retain and motivate their field crews through gamification, HR onboarding, Google review collection, and an AI assistant built into the product.
 

Stack
• Kotlin 2.2, Spring Boot 3.5, JDK 21
• PostgreSQL + pgvector, Flyway
• Spring AI (OpenAI, RAG / vector store, moving toward tool calling)
• WebSocket (in-app messenger: channels, presence, reactions)
• Quartz, Stripe, AWS S3
 

What you'll be doing
• Growing the monolith's domain modules: rewards/points, badges, leaderboard, check-ins, reviews, chat, subscriptions and more.
• Growing the product's AI layer. Today we have RAG search over FAQs and documents plus a few AI helper services (single-shot completion calls to OpenAI). Your job is to grow this into an agentic AI assistant with tool calling: the LLM calls business services as tools, works across multiple turns, and performs actions in the system (create an event, send a reminder, etc.) with user confirmation.
• Integrating the AI assistant into the existing in-app chat module (WebSocket).
• Working with the role-based access model — AI tools must inherit the same permissions as regular API endpoints.
 

What we're looking for
• Production Kotlin (not just the syntax) + Spring Boot / Spring Data JPA
• PostgreSQL: non-trivial queries, hands-on experience with migrations (Flyway/Liquibase)
• REST API design, transactions, Spring Security / JWT
• Required: real experience integrating LLMs into a backend — Spring AI, LangChain4j or direct OpenAI/Anthropic API calls, including function calling / tool calling. Not just "bolting GPT on for text generation".
• Nice to have: pgvector or another vector store, RAG architectures
• Bonus: WebSocket, Stripe API, AWS (S3), Quartz / schedulers

Experience
• 3+ years of commercial development in Kotlin/Java + Spring
• At least one shipped project with an LLM integrated into a production backend (not a pet project) — we'll dig into tool calling and agentic patterns during the interview
• Product team experience (rather than an outsourcing pipeline) is a plus: we need someone who understands the business logic, not just tickets
• English good enough for documentation and day-to-day communication with US stakeholders
 

How you work (important)
We expect you to write code alongside an AI agent (Claude Code, Cursor, etc.) as a primary tool, not just for line autocomplete. This isn't about "AI does the work for you" - it's about speed, and about being able to quickly verify and justify any code you commit, no matter who wrote it. 
 

In your cover letter, briefly tell us which AI coding tool you use and how you typically brief it. Applications without this will not be prioritized.
 

Ajax Systems, an international tech company and the largest manufacturer of security systems in Europe.
We are looking for a new team member to join our System devisions as Java Developer.

The System Division is responsible for building and developing the Ajax software ecosystem. The team develops and maintains OS Malevich and the Video Management System, builds scalable cloud infrastructure, and creates client applications for multiple platforms, ensuring that all system components work together as a unified ecosystem.

The division works with Java, Kotlin, Swift, C, C++, and Python. It includes embedded, cloud, mobile, and desktop engineers who ensure the stable operation of Ajax as a single digital platform.

 

Required Experience:

• Java: 4+ years of professional backend development in enterprise environment
• Kotlin: Knowledge and practical work experience
• Java Concurrency: Strong understanding and practical application experience

Architecture & Design:

• Understanding of SOA, microservice, and event-driven architecture
• Cloud development principles with practical AWS experience
• Ability to scale and ensure high availability of loaded systems
   

Technologies & Tools
Required:

• MongoDB, NATS
• Enterprise-grade stack (messaging brokers, in-memory storages, NoSQL, key-value databases)
• Docker and Kubernetes (containerized applications)
• Git, Gradle, Jenkins

Nice to Have:

• Redis, Netty, Akka, gRPC, Project Reactor

We offer:

• The opportunity to suggest and implement your own ideas that directly influence the product and its mass production
• A place in a fast-growing company with a motivated and professional team
• Competitive salary
• Medical insurance
• English classes
• The opportunity to participate in Ajax’s internal beta-testing program for security systems
• Discounts from partner companies
• Discounts on Ajax products
   

Ajax Systems is a Ukrainian success story that has grown into a global product. Ajax devices are trusted by more than 4.5 million end users and 330,000 PRO users in over 180 countries. The company provides comprehensive solutions to protect residential and commercial properties of all sizes. Today, Ajax portfolio includes 280 devices for intrusion protection, video surveillance, fire safety, and comfort and automation.

About Us

Peratera is a UK-based fintech company, founded in 2022 and authorised by the FCA as an Electronic Money Institution. We are building a modern, all-in-one payment platform that enables businesses to manage global payments and financial operations seamlessly.

Our solution allows companies to open multi-currency accounts, send and receive payments worldwide, and manage cross-border transactions from a single platform. Our mission is to simplify global finance and remove friction from international business operations.

Your mission

As a Middle Java Engineer, you will be part of the team building and evolving the core services behind our financial platform.

This is a hands-on engineering role where you will have the opportunity to contribute to technical decisions, improve existing solutions, and help shape the future of product.

Your Tech Environment

You will work in a modern, cloud-native stack with clear ownership and no legacy surprises:

• Backend: Java 17+, Spring Boot (Core, Security, Data, Cloud), REST APIs, event-driven services, Camunda
• Infrastructure: AWS (EKS, RDS, CloudWatch), Docker, Kubernetes, GitLab CI/CD
• Data & Messaging: PostgreSQL, AMQP / Kafka-style message brokers, event-driven architecture
• Observability: OpenSearch / ELK, Prometheus / Micrometer, OpenTelemetry (in progress)
• Integrations: Open Banking providers, banking partners, external payment systems

What You’ll Do

• Design, develop, and maintain core platform services, including payment flows, transaction lifecycle, reconciliation, and wallet infrastructure
• Participate in architecture discussions and contribute to technical solutions aligned with the overall platform direction
• Write clean, maintainable, and well-tested code following established engineering standards
• Collaborate with other engineers through code reviews, knowledge sharing, and technical discussions
• Translate business and technical requirements into reliable and scalable backend solutions
• Work closely with Product and DevOps teams to deliver financial features end-to-end
• Contribute to the platform’s evolution toward AI-assisted and data-driven capabilities
• Help improve platform reliability, fault tolerance, observability, and performance at scale

What We’re Looking For

• 3+ years of commercial experience with Java in production environments
• Hands-on experience with the Spring Boot ecosystem and backend application developmentDeep expertise in the Spring Boot ecosystem and distributed systems at scale
• Experience working with distributed systems and developing scalable backend services
• Experience building or supporting financial products, such as payments, wallets, banking, or fintech solutions
• Good understanding of software engineering practices, including clean code, testing, and code reviews
• Strong experience with REST API development and messaging systems
• Comfortable working in a distributed, international team and collaborating asynchronously
• Familiarity with cloud environments, CI/CD pipelines, and observability tooling

Nice to Have

• Previous experience in fintech, banking, payments, EMI, or other regulated financial environments
• Familiarity with payment-related compliance requirements, including PCI DSS
• Exposure to Open Banking providers or integrations with payment schemes
• Experience with Camunda or other workflow orchestration tools
• Fully remote setup with flexible hours and an international, highly skilled team

What You’ll Get

• Competitive, market-aligned compensation — discussed openly at first interview
• Direct impact on architecture and strategic platform decisions from day one
• A real fintech platform running at production scale — not a demo environment
• Exposure to modern cloud-native, AI-assisted, and Open Banking systems
• Fully remote setup with flexible hours and an international, highly skilled team

Sounds like a match? Send us your CV — we’re excited to get to know you.

We are looking for a Java Developer with experience in real-time communication technologies to join our team. In this role, you will focus on maintaining, optimizing, and extending an established real-time communication platform, working with both backend services and core frontend interactions.

What you'll do:

• Maintain and expand our existing real-time streaming and communication system.
• Design, build, and optimize backend services using Java and Spring Boot.
• Handle frontend logic using Vanilla JavaScript and jQuery for seamless media delivery.
• Work with real-time protocols (WebRTC, WebSockets) to ensure low-latency media streaming and data exchange.

• Troubleshoot, refactor, and improve legacy code to boost performance and stability.

   

You'll be a great fit if you have:

• Strong experience with Java 8+ and Spring Boot 2.4+.
• Solid hands-on experience with real-time communication protocols, specifically WebRTC and WebSockets.
• Good understanding of relational databases (MySQL or MariaDB).
• Proficiency in frontend basics: VanillaJS and jQuery.

• Willingness and ability to work with an established legacy codebase (refactoring, feature addition, and maintenance).

   

Would be a plus:

• Experience with media servers/SFU frameworks like mediasoup.
• Practical experience with Node.js.

We ensure your growth with:

• Competitive salary fixed in USD
• Flexible working schedule and fully remote work format
• Paid vacation days and sick leave days 
• Personal and professional development opportunities
• Participation in building innovative projects from scratch using modern technologies
• Team-building activities and corporate events
• English classes and educational events.

!!! Location: only Poland !!! 

Who we are:

Adaptiq is a technology hub specializing in building, scaling, and supporting R&D teams for high-end, fast-growing product companies in a wide range of industries.

About the Product:

Our client is a major online gaming operator building a next-generation transactional platform for user account management. This is a greenfield project designed to operate in a highly regulated, high-volume environment and support millions of concurrent users. The platform will process financial transactions in real time and must ensure high availability, sub-second performance, data integrity, security, and full auditability. One of the key engineering challenges is maintaining reliability and performance during extreme traffic spikes and peak events. 

The team is looking for strong technical expertise to help design and build a scalable, high-performance, and reliable backend platform that can meet strict security, regulatory, and compliance requirements.

About the Role:

As a Senior Java Engineer, you will design and build the core backend services of the PAM platform from the ground up. You will own features end-to-end, from technical design and implementation to automated testing, production monitoring, and release. You will work closely with Principal Engineers on architecture and technical decisions, contribute to RFCs, and deliver production-ready code. You will have a high level of autonomy and real influence over the platform’s design, while taking strong ownership of reliability, performance, and correctness in a critical financial system.

Key Responsibilities:

• Design and build backend services in Java 17+ (Spring Boot or similar) for wallet transactions, ledger entries, payment orchestration, bonus mechanics, and account state management.
• Develop REST APIs and event-driven integrations using Kafka or similar technologies for player-facing frontends, operations tooling, and external partners.
• Ensure correctness and reliability through idempotent operations, clear transaction boundaries, explicit failure handling, and strong unit, integration, and contract testing.
• Embed regulatory requirements into the platform, including KYC/AML checks, responsible gaming controls, and audit trails.
• Ensure production readiness with metrics, structured logging, distributed tracing, alerting, and participation in on-call rotations.
• Contribute to technical design and RFCs, participate in code reviews, and mentor other engineers.
• Use AI-assisted development tools as part of the daily workflow, following platform standards for context and prompts.
• Support live migration from the existing third-party platform, including parity testing, data validation, and cutover coordination.

Required Competence and Skills:

• 5+ years of backend engineering experience with strong hands-on expertise in Java 17+ and a modern framework such as Spring Boot.
• Proven experience building and operating high-integrity transactional systems such as payments, wallets, billing, banking, e-commerce, or gaming.
• Strong relational database expertise (PostgreSQL or equivalent), including schema design, ACID transactions, locking, and performance tuning.
• Experience with event-driven architecture and messaging (Kafka, RabbitMQ, or similar), including idempotency and retry mechanisms.
• Strong testing practices, including automated unit, integration, and contract tests as part of the standard development process.
• Hands-on production experience with containers, CI/CD pipelines, monitoring/telemetry, and production incident troubleshooting.
• Solid understanding of multi-threading, system architecture, and fault-tolerant design patterns.
• Good written and spoken English, with experience working effectively in distributed, multi-time-zone teams.

Nice to Have:

• Experience in iGaming, sports betting, fintech, or another regulated, high-transaction-volume domain.
• Exposure to Kubernetes and AWS, including VPC, IAM, EKS, and auto-scaling.
• Experience with compliance-driven development, including KYC/AML, responsible gaming, and audit requirements.
• Experience with AI coding assistants and agentic development workflows.
• Polish and/or Spanish language skills.

Why Us:

We provide 20 days of vacation leave per calendar year (plus official national holidays of a country you are based in).

We provide full accounting and legal support in all countries we operate.

We utilize a fully remote work model with a powerful workstation and co-working space in case you need it.