Jobs Java

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.

Our client is a software product company building enterprise applications focused on data, analytics, and AI-powered workflows. They are looking for a Senior Java Backend Engineer to help design, build, and scale the backend systems that power their products.

Responsibilities

• Design, develop, and maintain backend services using Java and Spring Boot;
• Build scalable and reliable microservices and distributed systems;
• Design and optimize PostgreSQL databases, queries, and data models;
• Develop and maintain REST APIs and backend integrations;
• Implement event-driven solutions using NATS messaging;
• Improve system performance, scalability, and reliability;
• Participate in architecture discussions and technical design;
• Collaborate with frontend engineers and product stakeholders;
• Review code and contribute to engineering best practices;
• Troubleshoot and resolve production issues.

Requirements

• 5+ years of professional software development experience;
• Strong Java and Spring Boot experience;
• Experience building scalable backend systems and microservices;
• Strong PostgreSQL knowledge, including query optimization and database design;
• Experience with messaging systems, preferably NATS;
• Experience designing and implementing distributed systems;
• Proven experience scaling applications and services under increasing load;
• Experience developing and maintaining REST APIs;
• Strong understanding of software design patterns and backend architecture;
• Experience with testing, debugging, and performance optimization;
• Strong communication and problem-solving skills.

Preferred

• Experience with Docker and Kubernetes;
• Experience with cloud platforms (AWS, Azure, or GCP);
• Experience with AI-powered products, analytics platforms, or enterprise SaaS applications;
• Previous technical leadership experience.

!!! 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.

About Us: InnovatelU is a dynamic tech company delivering cutting-edge solutions. We're looking for a passionate Java Developer to join our team. If you have a solid Java foundation, are eager to grow, and learn quickly, we want to hear from you! 

Requirements: 
- Strong knowledge of Java 
- Knowledge of Spring (Spring Core, Spring AOP, Spring MVC, Spring Security, Spring Boot) 
- Familiarity with REST APIs, web services 
- Proficiency in version control tools (Git) 
- Experience with build tools like Maven and Gradle 
- Experience with relational databases (PostgreSQL) 
- Expertise in containerization (Docker) 

- Experience in unit and integration testing 
- Strong communication skills and teamwork ability 
- English level: Intermediate or higher 

Will Be a Plus: 

- Solid understanding of design patterns 

- Experience with NoSQL databases like MongoDB and Redis 

- Familiarity with messaging systems like Kafka and RabbitMQ 

- Experience with microservices architecture 

Responsibilities: 

- Collaborate with senior developers and project managers 

- Assist in designing, coding, and testing applications 

- Write well-designed, efficient, and testable code 

- Participate in code reviews 

- Debug and resolve technical issues 

- Contribute to application documentation 

Interview Stages: 

1. Test Task: 1 hour 

2. HR Interview: 30 minutes 

3. Technical Interview: 1 hour 

We Offer: 

- Full Remote 

- Constant support and mentoring 

- Paid 5 working days of sickness per a year; 

- Paid all official Ukrainian holidays; 

- 18 working days of vacation per a year; 

- Opportunity for professional growth and career development 

If this sounds interesting to you, let's talk!

We are looking for a Senior Java Engineer / Architect with strong experience in HSM (Hardware Security Modules) to join a potential new project.We are looking for someone who has designed or co-created the architecture of HSM-based solutions in production environments and can help define the right technical approach for a new system.

🎯 Ideal Candidate

We are particularly interested in candidates who have personally designed, implemented or significantly contributed to production systems using HSM, rather than only having theoretical knowledge of the technology.

🔹 Key Responsibilities

Design and implement solutions integrating HSM into production systems

Contribute to the architecture of secure systems using HSM

Design and manage the lifecycle of cryptographic keys

Integrate Java applications with HSM solutions

Work with cryptography, PKI, certificates, encryption and secrets management

Define and implement secure key management solutions

Contribute to technical and architectural decisions for systems requiring a high level of security

🔹 Requirements

Strong Java development experience

Hands-on experience with HSM

Experience designing and implementing HSM-based solutions

Strong knowledge of cryptographic key management and key lifecycle

Experience integrating applications with HSM

Good understanding of:

Cryptography

PKI

Digital certificates

Encryption

Secrets management

KMS / Key Vault / Vault

Strong technical or architectural background in high-security systems

⭐ Nice to Have

Experience in banking, payments, fintech or other regulated environments

Experience with banking systems and cryptographic solutions

Experience configuring and deploying HSM

Experience designing Key Management Systems

Experience with PKI / KMS / Key Vault / Vault

Previous involvement in the architecture of secure financial systems

Blackthorn Vision is seeking a Senior Backend Developer (Java/Node.js) for an outstaff project with a global leader in energy technology. Founded in 1926 and headquartered in Houston, Texas, the company has 100,000 employees serving customers in more than 120 countries and develops software solutions for automation across the energy and industrial sectors.

You will work as part of an international team, collaborating with Blackthorn Vision specialists, client-side engineers, and management. We are looking for a self-driven team player with strong problem-solving skills, a commitment to quality, and a passion for delivering robust and maintainable software solutions. Upper-Intermediate English or higher is required for effective day-to-day communication. The position follows a regular full-time working schedule aligned with the Ukrainian time zone.

Required Qualifications:

• 5+ years of professional software development experience.
• Strong hands-on experience with Java, Spring Framework, and Spring Boot.
• Hands-on experience with Node.js and TypeScript.
• Experience with Microservices Architecture, Event-Driven Architecture, and REST APIs.
• Strong understanding of system architecture and business requirements.
• Hands-on experience with Kafka and RabbitMQ.
• Experience with PostgreSQL, Cassandra, Redis, or similar relational/NoSQL databases.
• Experience with Docker, Kubernetes, Microsoft Azure, and Azure IoT Hub.
• Experience with CI/CD, DevOps practices, and modern observability tools.
• Experience using AI-assisted development tools such as GitHub Copilot, Microsoft Copilot, Cursor, or similar.
• Excellent problem-solving, communication, and collaboration skills.

Nice to have:

• Experience working with operational and time-series data.
• Bachelor’s degree in Computer Science, Software Engineering, Information Technology, or a related field.

Please note: We are open to considering candidates based abroad; however, we can offer cooperation only under Ukrainian contracting arrangements.

Please provide your CV and LinkedIn profile. We demand your LinkedIn profile with actual working experience to move forward with your application!

Fundomate is looking for a Senior Java Back-End Developer to join our team. Fundomate is an innovative fintech company operating in the alternative lending space and providing both direct-to-business and white-label turnkey solutions.

You will be good match if:

- You have history of solving non trivial problems in one of your previous projects

- You have wide technology background (backend, frontend, devops, ops, mobile development, etc), so you will understand the connections between technologies and expand this knowledge with domain and business needs. 

- You have experience working in US fintech domain 

We will be good match if:

- You want to solve (or learn to solve) complex business problems

- You want to experiment with processes/development technics/tools

- You are interested in continuous improvement and automation of product and working process

Requirements:

- 6+ years of experience developing web applications

- 3+ years of experience in any IoC & DI framework (Spring, Quarkus, Micronaut, etc.)

- TDD experience in production is a must have

- Experienced in pair programming

- Good knowledge of MicroServices (Kubernetes knowledge is a plus)

- Experience working with tools like Git, Gradle, Jenkins or similar CI/CD

- Working experience in Industry Standard protocols related API Security including OAuth (KeyCloak is a plus)

- Working experience with RDBMs like Postgres/MySQL or any similar

- Understanding of asynchronous message-based communication like Kafka, GCP Pub/Sub, AWS SNS/SQS, etc. (Kafka as an advantage)

- Strong Agile/Scrum/Kanban development experience

- Experience in third party systems integration (XML or JSON api)

- Knowledge of any cloud provider (AWS as an advantage)

Our technical Stack:

- Java 25

- Microservices (Quarkus)

- Postgresql/MySQL

- Kafka

- Keycloak

- Kubernetes & Docker

- AWS (EKS, MSK, RDS, etc.)

- Gradle

- Bitbucket pipelines, gitops approach

- Lombok, MapStruct, Flyway

We offer:

- Innovative product with modern technology stack

- Competitive salary (paid in $)

- Social package (paid vacations, sick leaves and etc)

- PE accounting and support

- WFH and remote working mode possibility, Ukrainian working hours

- No bureaucracy, micromanagement and time-tracking

Description

The company operates within the financial services sector, providing essential technology solutions that underpin modern financial operations. It specializes in developing robust platforms and applications designed to enhance efficiency and security for a diverse range of financial institutions. These solutions often involve advanced data processing, secure transaction management, and sophisticated analytical tools. The organization plays a crucial role in enabling its clients to navigate complex regulatory landscapes and deliver superior services to their own customers. Its focus is on leveraging cutting-edge technology to drive innovation and stability across the financial ecosystem.

Requirements

• Enterprise Java Development: 3 to 6 years of professional software engineering experience, focusing on building robust backend systems (experience in the financial sector is highly valued).
• Spring Boot & Spring AI: Solid intermediate experience developing and maintaining microservices with Spring Boot. Practical experience utilizing Spring AI to seamlessly connect enterprise Java applications with modern AI models.
• Generative AI & LLM Integration: Hands-on experience developing solutions that leverage Large Language Models (LLMs), with specific practical application of Anthropic Claude models for natural language processing and generation tasks.

• AI Rate Limits & Token Economics: A solid understanding of LLM operational mechanics and cost awareness, including:

  – The ability to develop and handle API workflows within RPM (Requests Per Minute) and TPM (Tokens Per Minute) constraints.

  – Understanding the pricing structures and technical differences between Input, Output, and Cache tokens.

  – Applying best practices to optimize prompts and context to manage latency and operational costs effectively.

•  Engineering Fundamentals: Proven ability to implement and consume RESTful APIs securely and efficiently. Strong practical knowledge of Git version control, including branching strategies and standard collaborative workflows.

Job responsibilities

• Implement robust backend services and APIs using Java and Spring Boot frameworks.
• Develop scalable and efficient solutions for integrating Generative AI and LLM capabilities into existing systems.
• Build and maintain core components of financial applications, ensuring high performance and reliability.
• Enhance existing Java-based microservices to support new features and optimize performance.
• Analyze system requirements and technical specifications to design effective software solutions.
• Develop and integrate RESTful APIs for seamless communication between various system modules.
• Maintain code quality, perform code reviews, and ensure adherence to best practices in software development.
• Troubleshoot and resolve complex technical issues within the Java application stack.
• Contribute to the continuous improvement of development processes and tools, including Git workflows.
• Develop unit and integration tests to ensure the stability and correctness of implemented features.

About Us

Smart Capital Center is an end-to-end, AI-powered platform for Commercial Real Estate (CRE) investment and financial management. We power real-time underwriting, asset management, and portfolio analytics through a combination of live data, workflow automation, and AI-driven insights.

Operating at the intersection of Generative AI, finance, and real estate, we are building systems that digitize and simplify complex financial workflows.

Our clients include leading institutions such as JLL, Pacific Life Insurance Company, and KeyBank. We are a lean, high-performance team building category-defining technology in a $17 trillion industry.

To learn more about our platform and vision, please visit our website.

The Role

We are looking for a Backend Software Engineer with strong experience in building scalable systems and a deep interest in AI-powered applications.

This is a high-impact, hands-on role where you will design and build backend services, integrate AI capabilities, and develop intelligent, agent-driven workflows used in real-world production environments.

You will work closely with product, AI, and engineering teams to deliver reliable, high-performance systems and automation features.

What You Will Do

Backend Development

• Design, build, and maintain backend services using Java (Spring Boot) and Python
• Develop scalable APIs and microservices for data-intensive applications
• Optimize system performance, reliability, and scalability
• Design efficient data models and handle complex integrations

AI & Intelligent Systems

• Implement and integrate AI-powered features into core products
• Design and build agent-based workflows for automation and decision-making
• Apply prompt engineering techniques to improve LLM outputs and behavior
• Work with modern AI frameworks to productionize intelligent systems

Cloud & Infrastructure

• Develop and deploy backend systems on AWS (EC2, S3, RDS, Lambda, etc.)
• Build resilient, scalable cloud-native services
• Contribute to system monitoring, logging, and reliability

System Design & Engineering Excellence

• Contribute to architecture, service boundaries, and system design decisions
• Write clean, maintainable, and well-documented code
• Ensure security, performance, and operational stability
• Continuously improve engineering quality and development practices

Collaboration

• Work closely with frontend, product, and AI teams
• Contribute to end-to-end feature delivery
• Participate in Agile development processes

Requirements

• 5+ years of backend software development experience
• Strong experience building and scaling backend systems in production

Core Technical Skills

• Strong experience with Java and Spring Boot
• Solid experience with Python
• Strong knowledge of SQL and database design (PostgreSQL preferred)
• Experience building REST APIs, microservices, and distributed systems
• Hands-on experience with AWS (EC2, S3, RDS, Lambda, etc.)
• Proficiency with Git and modern development workflows

AI & Modern Development Experience

• Experience with prompt engineering for LLM-based systems
• Practical experience building AI agent workflows in production
• Familiarity with frameworks/tools such as:
  • LangGraph
  • LangChain
  • LangSmith
  • or similar ecosystems
• Experience using AI-assisted development tools, such as:
  • Claude Code
  • Codex
  • OpenCode
  • or similar

Nice to Have

• Experience with vector databases or semantic search (e.g., Milvus)
• Knowledge of RAG (Retrieval-Augmented Generation) architectures
• Experience with CI/CD pipelines and DevOps practices
• Familiarity with event-driven architecture

• Experience with data processing pipelines or document AI systems

   

Why Join Us

• Work on cutting-edge AI-powered systems in a $17T industry
• Build real-world applications using LLMs, agents, and automation
• High ownership and autonomy with meaningful technical impact
• Opportunity to influence system design and engineering direction
• Fast-moving, execution-focused team with minimal bureaucracy
• Competitive compensation and flexible work environment

Level: Senior Engagement: Long-term contract Location: Europe (EU / EEA / UK), remote Working hours: EU business hours, shifted 2–3 hours later to ensure daily overlap with US West Coast (PST/PDT) mornings

About the Client

Our client is a leading enterprise data platform company building an open, high-performance data lakehouse for AI and analytical workloads. The platform combines an intelligent SQL query engine, an AI-ready semantic layer, and an open catalog built on Apache Iceberg — enabling Fortune 500 companies across finance, energy, manufacturing, and logistics to unify, query, and govern data at massive scale across cloud and on-premise sources.

About the Role

We are looking for a Senior Software Engineer to design, build, and own significant components of the core query engine of a large-scale distributed data platform. You will lead work across query planning, optimization, and execution — driving architectural decisions, mentoring middle engineers, and pushing the platform's performance and scalability boundaries across all major clouds.

This is a systems-level, backend engineering role focused on distributed data processing internals — not application development or CRUD services.

Responsibilities

• Architect, design, and implement significant components of the query engine — planner, optimizer, execution operators, memory management, and data access layers.
• Write and review high-quality, performance-critical code in Java and/or C++.
• Own end-to-end delivery of features from technical design through production rollout.
• Drive performance optimization work — profiling, benchmarking, and eliminating bottlenecks in latency- and throughput-sensitive paths.
• Integrate deeply with columnar formats, open table formats, and connectivity drivers.
• Mentor middle engineers, lead code reviews, and set technical standards for the team.
• Contribute to CI/CD architecture and quality processes across Jenkins, containerization, and multi-cloud deployment (GCP, AWS, Azure via Kubernetes / Docker).
• Debug complex, cross-layer issues spanning query planning, distributed execution, memory management, and I/O.
• Partner with US-based engineering leads on design reviews, architectural decisions, and roadmap execution.

Required Qualifications

• Education: B.S. or M.S. in Computer Science, Computer Engineering, or a related technical field.
• Programming: Strong proficiency in Java or C++, with deep understanding of OOP, systems design, memory management, and concurrency. Candidates strong in both are especially valued.
• SQL & Data: Advanced SQL skills and strong understanding of query execution internals — planning, optimization, and operator implementation.
• Data processing systems experience: Demonstrated experience building or extending data processing systems — query engines, distributed databases, ETL/ELT frameworks, or analytical platforms.
• Engineering experience: 5+ years in backend/systems software engineering, with a track record of owning significant components.
• CI/CD & DevOps: Solid experience with Jenkins and modern engineering workflows.
• Containers & Orchestration: Strong working knowledge of Docker and Kubernetes.
• Cloud: Hands-on experience with at least one major cloud (GCP, AWS, or Azure); exposure to more than one is a strong plus.
• Version Control: Confident with Git / GitHub workflows and rigorous code review practices.
• English: Upper-Intermediate or higher (B2+) — daily written and verbal communication with a US-based engineering team.
• Availability: Able to work EU hours with a 2–3 hour shift toward US West Coast time to ensure daily overlap with the client team.
• Leadership: Prior experience mentoring engineers, leading technical designs, or owning components end-to-end.

Desired Skills

• Deep experience with Apache Arrow (columnar in-memory format).
• Hands-on experience with Apache Calcite (SQL parsing, planning, optimization framework).
• Experience with Gandiva or LLVM-based expression compilation and code generation.
• Experience with open table formats — Apache Iceberg, Delta Lake, or Hudi.
• Deep familiarity with distributed computing frameworks (e.g., Apache Spark, Kafka) and MPP SQL query engines (e.g., Presto, Trino, or similar).
• Deep understanding of query planning, optimization (cost-based, rule-based), and execution internals.
• Experience with data connectivity drivers: JDBC, ODBC, Arrow Flight.
• Kubernetes on managed services (GKE / EKS / AKS) and multi-cloud exposure.
• IaC tools such as Terraform.
• Track record of performance optimization at the systems level — profiling, vectorization, cache/memory-conscious design.
• Prior experience contributing to open-source data infrastructure projects.

We are looking for an experienced Senior Full Stack Engineer with strong Java/Spring Boot expertise to take ownership of production applications and work across backend, frontend, database, and cloud environments.

Responsibilities

• Design and develop scalable web applications and backend services using Java and Spring Boot
• Build and maintain REST or GraphQL APIs
• Develop and integrate modern frontend applications using React or Angular
• Design, optimize, and maintain relational database models
• Integrate third-party services and enterprise systems
• Implement automated testing and CI/CD pipelines
• Participate in architecture and technical-planning discussions

• Take ownership of development tasks and delivery

   

Requirements

• 5+ years of professional software-development experience
• Strong commercial experience with Java and Spring Boot
• Solid knowledge of SQL and relational databases, preferably PostgreSQL
• Experience with React, Angular, Vue.js, or Next.js
• Experience with Docker, cloud deployment, and CI/CD
• Strong understanding of REST APIs and modern web application architecture
• Ability to work independently and take ownership of delivery

• Professional English

   

Nice to have

• AWS or Azure
• Kubernetes and Terraform
• Kafka, RabbitMQ, or other event-driven technologies
• Microservices and enterprise integrations
• GraphQL
• AI/LLM integration experience
• Experience in FinTech, banking, insurance, healthcare, or other regulated domains

Application Process

This is an application to join CML Team. Selected engineers will be contacted when a suitable project matches their experience, availability, location, and rate.

To apply: Please include your CV, current location, availability, preferred contract type, and expected hourly or daily rate.

Sii Ukraine is a subsidiary of Sii Poland — the leader in IT, engineering, and consultancy services with over 7500 IT experts in Poland and more than 250 prestigious customers. We are looking for ambitious and top-quality professionals to join our project teams. 

We are looking for a Java Technical Lead to join a long-term international project focused on consulting, development, and enhancement of an application supporting complex sales processes.
 

In this role, you will act as the Single Point of Contact (SPOC) for the Sii team, working closely with customer stakeholders and coordinating technical activities within a team of four engineers. While this is not a leadership role for the entire project organization, you will be responsible for providing technical guidance, driving architecture and development decisions, and ensuring smooth collaboration between the customer and the Sii delivery team.

This is an excellent opportunity for a senior engineer who combines strong hands-on development expertise with consulting, communication, and technical leadership skills.

Your tasks:
 

• Act as the primary technical contact and SPOC for the Sii team, facilitating collaboration with customer stakeholders and supporting consulting activities.
• Lead the design, development, and further enhancement of applications supporting complex sales processes, providing technical guidance and mentoring to the development team.
• Develop and maintain backend solutions using Java and Spring Boot, support frontend development in Angular, and contribute to system integrations based on SOAP and REST services.
• Work with Azure AD and OpenID Connect to ensure secure authentication and authorization mechanisms across the application landscape.
• Manage and optimize application delivery processes using GitLab Pipelines, maintain automated end-to-end tests with Cypress, and promote software quality best practices.
• Support data integration and interoperability activities involving SAP IDoc, XML, WSDL, and JSON structures, while contributing to infrastructure-related topics when required.

Requirements:
 

• Strong experience in Java development, including Spring Boot, gained in complex enterprise environments.
• Practical knowledge of Angular, PostgreSQL, SOAP and REST-based integrations.
• Experience with Azure AD, OpenID Connect, CI/CD processes, and GitLab Pipelines.
• Hands-on experience with automated testing, preferably Cypress E2E.
• Understanding of enterprise integration standards and data structures such as SAP IDoc, XML, WSDL, and JSON.
• Previous experience as a Technical Lead, Team Lead, Lead Developer, or a senior engineer coordinating development activities and stakeholder communication.
• Strong consulting, communication, and problem-solving skills.
• German at B2 level or higher is mandatory; English proficiency is also required.
• Experience with infrastructure-related topics is considered a strong advantage.
• Tax residency in Ukraine is required.