Jobs Java

About Our 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 for the connectivity stack of a large-scale data platform. The work spans three areas:

• Client connectivity — drivers and client libraries used by applications and BI tools
• Source connectivity — connectors to databases and data systems, including authentication, metadata discovery, and query/data pushdown, with certification and upgrade support
• Agent & service connectivity — tool interfaces and integrations for AI-agent access to the platform

Deep expertise in one of these areas is enough — you'll grow into the adjacent ones over time. This is a role for an engineer who cares about API and protocol stability, backward compatibility, and interoperability with the tools enterprises actually use. You will lead the design and delivery of substantial components, working within an established architecture alongside US-based engineering reviewers.

This is a systems-level, backend engineering role focused on drivers, protocols, and distributed services — not application development or CRUD services.

Responsibilities:

• Lead the design and delivery of connectivity components — client drivers, source connectors, and service integrations — turning ambiguous initiatives into well-scoped, reviewable milestones
• Produce technical designs, explain architectural trade-offs, and surface compatibility, security, and delivery risks early
• Maintain backward compatibility and API/protocol stability; build compatibility, interoperability, and performance test suites
• Develop and maintain connectors for major BI tools, collaborating with the technology partners behind them
• Diagnose complex client/server, protocol, and distributed-system failures; drive root-cause analysis of customer-reported and escaped defects
• Improve diagnostics, logging, observability, and supportability of the connectivity stack
• Contribute upstream to open-source projects (e.g., Apache Arrow) where agreed
• Mentor engineers, participate in code and design reviews, and communicate progress and risks clearly across a distributed team.

Required Qualifications:

• B.S. or M.S. in Computer Science, Computer Engineering, or a related field — or equivalent practical experience
• 8+ years of production software engineering experience
• Deep proficiency in Java or C++, and the ability to work effectively in another systems/services language
• Experience designing and debugging APIs, protocols, client libraries, or distributed services
• Strong fundamentals: data structures, concurrency, asynchronous programming, networking, and failure handling
• A track record of comprehensive testing — unit, integration, compatibility, and performance
• Experience with production CI/CD, release processes, and engineering quality controls
• Working knowledge of SQL
• Comfortable with AI-assisted development workflows — using modern AI tools productively while critically validating their output
• Clear written and verbal communication in a distributed engineering environment; English Upper-Intermediate or higher (B2+)
• Availability to work EU business hours shifted 2–3 hours later for daily overlap with US West Coast mornings.

Desired Skills:

• JDBC, ODBC, ADBC, or database-driver development experience
• Apache Arrow (including Arrow Flight)
• SQL engines, databases, or data platforms
• Source-connector development for databases, warehouses, or SaaS systems
• MCP or agent-tool integrations
• OAuth, OIDC, TLS, and enterprise authentication flows
• Cross-platform native build, packaging, and release experience
• BI-tool interoperability (Power BI, Tableau) and partner collaboration
• Observability and production diagnostics
• Open-source contribution experience.

Details:

• Engagement: Long-term contract
• Location: Europe (EU / EEA / UK), remote
• Working hours: EU business hours, shifted 2–3 hours later for daily overlap with the US West Coast team

About Our 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 for the data catalog and enterprise data management layer of a large-scale lakehouse platform — the services that automate data ingestion and autonomously optimize Apache Iceberg tables. You will own features through the full development cycle, from design through deployment, in a multithreaded, distributed environment where scalability, performance, and always-on availability are the baseline expectations.

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

Responsibilities:

• Own the full software development cycle — inception, design, development, testing, deployment — for catalog and data-management services
• Build and operate services for automated ingestion and autonomous optimization of Apache Iceberg tables
• Reason about concurrency and parallelization to deliver scalability and performance in multithreaded, distributed systems
• Drive performance tuning and system-efficiency improvements
• Work with Apache Foundation open-source projects, contributing upstream where agreed
• Participate in code and design reviews, upholding a high engineering bar
• Collaborate with product managers, support teams, and solution architects on feature requests and design updates
• Partner with US-based engineering leads on technical decisions.

Required Qualifications:

• B.S., M.S., or PhD in Computer Science or a related field
• 5+ years of software engineering experience, preferably focused on database systems or related fields
• Strong object-oriented programming skills in Java or C++
• Solid grounding in data structures and algorithms
• Hands-on experience with multithreaded and asynchronous programming patterns for scalable, performant systems
• A passion for engineering quality — zero-downtime upgrades, availability, resiliency, and uptime as first-class concerns
• Comfort with a fast-moving environment; strong ownership; the confidence to defend a technical position and the openness to be mentored
• Comfortable with AI-assisted development workflows — using modern AI tools productively while critically validating their output
• English Upper-Intermediate or higher (B2+) — daily written and verbal communication with a US-based engineering team
• Availability to work EU business hours shifted 2–3 hours later for daily overlap with US West Coast mornings.

Desired Skills:

• Database internals and query planning
• Distributed systems: concurrency control, data replication, storage systems
• Apache Iceberg or other open table formats (Delta Lake, Hudi)
• Messaging systems: Kafka, NATS, or cloud pub/sub services
• Contributions to open-source data infrastructure (Apache projects especially valued).

Details:

• Engagement: Long-term contract
• Location: Europe (EU / EEA / UK), remote
• Working hours: EU business hours, shifted 2–3 hours later for daily overlap with the US West Coast team

About Our 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 build and operate production AI agent and search services on top of a large-scale data platform. This is hands-on work at the intersection of distributed backend engineering and applied AI: multi-agent workflows, tool-execution infrastructure, retrieval and relevance, and integrations with multiple LLM providers — all running as real, customer-facing production services with the reliability expectations that implies.

Responsibilities:

• Design and implement scalable multi-agent workflows (including conversation state), tool-execution infrastructure, and data-aware tools working with catalogs, schemas, lineage, SQL, jobs, semantic metadata, data preparation, and visualizations
• Build search and retrieval capabilities with OpenSearch or equivalent — indexing, relevance tuning, hybrid keyword + vector search
• Integrate multiple LLM/model providers with secure configuration and graceful degradation
• Develop APIs and event contracts across REST, streaming/SSE, gRPC, protobuf, and SDKs, including UI integrations
• Operate, monitor, and improve production services — service health, logs, metrics, traces, search-cluster health, latency, and error rates; participate in the team's production-support model
• Investigate incidents, drive root-cause analysis, and ship durable fixes
• Design for permissions, tool approvals, multi-tenancy, and customer-data governance
• Maintain dependencies, apply security fixes, and reduce tech debt; produce designs, tests, runbooks, and documentation; lead technical discussions and review code.

Required Qualifications:

• B.S. or M.S. in Computer Science, Computer Engineering, or a related field — or equivalent practical experience
• 7+ years of relevant experience, or equivalent demonstrated senior-level impact
• Strong Java software engineering skills
• Strong grasp of concurrency, data structures, API design, testing, maintainability, and backward compatibility
• Solid background in distributed systems, microservices, cloud services, or data-intensive backends
• Hands-on experience with search technologies — OpenSearch, Elasticsearch, or Lucene — including vector search, embeddings, or relevance systems
• Experience building LLM applications, agent/tool workflows, RAG systems, or model-provider integrations
• Strong production instincts: diagnosing failures via logs, metrics, and traces; designing for fault tolerance, retries, cancellation, and recovery
• SQL and familiarity with data platform concepts: catalogs, metadata, schemas, governance, lineage
• Comfort leading ambiguous, cross-service work with clear stakeholder communication and strong written documentation
• Comfortable with AI-assisted development workflows — using modern AI tools productively while critically validating their output
• English Upper-Intermediate or higher (B2+) — daily written and verbal communication with a US-based engineering team
• Availability to work EU business hours shifted 2–3 hours later for daily overlap with US West Coast mornings.

Desired Skills:

• LangChain4j or similar agent frameworks
• Python for AI services, evaluation harnesses, or sandboxed execution
• React and TypeScript
• gRPC, protobuf, Quarkus, Kubernetes, MongoDB, KV stores, event-driven architectures
• Apache Arrow, Apache Iceberg, OpenLineage, semantic layers, or data-governance systems
• AI quality evaluation: LLM-as-judge, model benchmarking, production AI metrics
• OpenSearch operations: index lifecycle management, relevance tuning, incident response
• Open-source contributions.

Details:

• Engagement: Long-term contract
• Location: Europe (EU / EEA / UK), remote
• Working hours: EU business hours, shifted 2–3 hours later for daily overlap with the US West Coast team

Project Description:

Luxoft is seeking motivated Appian developers to join our expanding Appian Digital Automation Practice in India. You will have the opportunity to work with our global clients on digital transformation initiatives and contribute to the Appian Center of Excellence for our customers.

You will collaborate with high-caliber project teams composed of engineers with deep technical expertise and domain knowledge, providing significant opportunities for learning, growth, and career advancement. We support cross-training in BPM, RPA, and related technologies through certification reimbursement programs.

Luxoft offers a competitive compensation and benefits package, including industry-leading insurance coverage in India. As you advance your career with Luxoft, you may also have the opportunity to pursue roles at our international offices through our Internal Mobility program.

Responsibilities:

- Collaborate with business partners to gather and analyze requirements.

- Design, develop, configure, test, deploy, implement, maintain, and enhance custom BPM workflows using Appian across the enterprise.

- Design and implement complex enterprise integrations with LDAP, Active Directory, and other internal systems.

- Design and develop database objects to support BPM applications.

- Maintain database performance by identifying and resolving production and development issues.

- Participate in workflow analysis and modeling using SQL Server and SQL Management Studio.

- Translate BPM requirements into Appian process model prototypes and solutions ensuring quality and performance.

- Deliver projects using Agile or Waterfall methodologies as specified.

- Conduct and participate in detailed design reviews to ensure compliance with approved architecture.

- Engage in daily activities of the Appian BPM development teams.

- Support enhancements to Appian applications, user access management, deployments, and database performance management.

- Collaborate with application support teams during development, deployment, and support phases.

Mandatory Skills Description:

• Possess a bachelor's degree in Computer Science, Engineering, or a related technical field from an accredited university or college..

• Have 4-6 years of software engineering experience, demonstrating proficiency in one or more of the following technologies: Appian, Scripting, REST API services, Java and JavaScript.

• Completed end-to-end implementation for at least 2 real-life Appian projects.

• Exhibit expertise in integrations utilizing Web API, Integrations, with the capability to tailor these functionalities to suit external system requirements.

• Showcase a robust grasp of database principles, coupled with practical experience in Stored Procs, MySQL or SQL Server.

• Demonstrate experience in Appian Process Models, Rules & Expressions, Data Management including Complex Data Types, XSDs, SQL, Inter Process Communication, RBAC, and Process Reporting on Appian 20.X and above.

• Possess Appian Certification as per your experience level.

• Embrace an agile mindset and have a level of familiarization with Agile methodologies along with having a knack for crafting solutions that facilitate business process automation.

• Offer a blend of technical prowess, strong business acumen, leadership abilities, and a track record of effective knowledge transfer.

Nice-to-Have Skills Description:

SQL, Integrations, Agile Methodology, Scripting

Project Description:

We are building the platform, which supports various information gathering and processing across the bank and providing access to this data through both private and public cloud approach. The solution will be built from the scratch using the latest technologies.

Responsibilities:

- Write good and well-tested code using Java
- Write Test Cases and User/Supporter Documentation of your code
- Development environment support (mostly automation using Jenkins CI, Bash)
- Evaluate and adopt new development tools, libraries and approaches to improve quality
- Perform peer code review of project codebase changes

Mandatory Skills Description:

- At least 6 years of experience in the industry of software development
- At least 5+ years of experience in Java
- Deep knowledge and usage of SQL (Oracle or PostgreSQL dialects is preferable)
- It is essential for a candidate to have/be able to do livecoding, understand the code and fix it fast

Nice-to-Have Skills Description:

- Experience with Messaging Systems: RabbitMQ, Kafka, etc.
- Experience with Kubernetes and Docker
- Linux user

Languages:

• English: B2 Upper Intermediate

About B2Spin

We are B2Spin, and we are dedicated to delivering the best Free-to-Play Social Casino and gaming experiences by creating captivating, engaging, and unique products that are accessible to everyone. We have built a team of talented professionals from all over the globe, who are working to continually improve the experiences of our players. We are not looking to just be part of the industry, but to revolutionize it.

AI-Driven Engineering Culture

We are actively building an AI-driven engineering organization with a clear and deliberate stance: artificial intelligence is a core part of how we build and deliver software — not an experiment, not a trend, and not an optional add-on.

AI is embedded into our engineering workflows, from system design and prototyping to refactoring, testing, and code review. We expect engineers to be fully comfortable working in AI-driven environments and to treat AI as a primary productivity multiplier. Strong engineering judgment, architectural ownership, and accountability remain essential—AI amplifies our engineers, it doesn’t replace responsibility for technical decisions.

What you will be doing
• Design, evolve, and maintain core libraries, framework extensions, and shared components used across all engineering teams
• Take ownership of system performance, scalability, and high-load architecture, ensuring core services can handle massive throughput with low latency
• Proactively monitor production behavior, investigate complex application/database performance bottlenecks, and introduce advanced metrics, dashboards, and alerting systems
• Establish and advocate for best practices in concurrency, memory management, and resource utilization across the backend ecosystem
• Collaborate with cross-functional teams including backend, web, mobile, QA, and product teams
• Take ownership of specific functional areas within our large-scale architecture
• Leverage AI tools and assistants as integral parts of your development workflow—from system design to code review
• Contribute to maintaining high test coverage, predictable production behavior, and seamless scalability
• Drive engineering excellence through modern practices and continuous improvement

What we are looking for
• Deep, low-level understanding of Java internals (JVM, GC behavior, memory management, concurrency/multithreading, and performance profiling)
• Advanced knowledge of relational databases (PostgreSQL), including query optimization, indexing strategies, locking mechanisms, and connection pooling under heavy load and distributed systems architecture, specifically high-throughput event streaming with Kafka (partitioning, replication, consumer group rebalancing, and tuning).
• Strong system design, troubleshooting and debugging capabilities
• Comfortable and proactive in using AI coding assistants (GitHub Copilot, Claude Code, etc.) as productivity multipliers
• Practical experience validating, refining, and taking ownership of AI-generated output
• Upper-intermediate or higher level of English

Nice to have:
• Proven track record of building or maintaining shared libraries, SDKs, or internal tooling in a large-scale engineering organization.
• Hands-on experience with APM tools and observability stacks (Prometheus, Grafana, ELK) with the ability to define meaningful SLOs/SLIs, custom metrics, and proactive alerts.

Main technologies: Java, Spring, Spring Boot, Ebean-ORM, Quartz, Maven, Resteasy, Flyway, PostgreSQL 15, HTTP/Websockets, Netty, K8S/Docker, GCP, Jenkins, ELK, Grafana.

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 Description:

- 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:

- 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

Languages:

English: B2 Upper Intermediate

Numerical Technologies Ltd is a leading provider of custom software solutions and services specializing in risk, limits, and regulatory capital. Right now, we are looking for a Principal Java Engineer to join our team.

What you will be doing:

As part of the team, you will contribute to a strategic modernization initiative for a leading multinational financial services company. You will design, develop, and support scalable Java solutions while making key architectural decisions as the platform evolves from a monolithic application to a microservices architecture.

Working closely with product and engineering teams, you will design new service-based solutions, define service boundaries and integrations, build fault-tolerant services, and ensure high code quality through testing, code reviews, and system design.

Project: Modernization of a monolithic platform into a microservices architecture. Java services provide authentication, logging, and data management, while Python services implement core computational logic. The role combines hands-on development with architectural ownership of new solutions derived from existing business capabilities.

What we’re looking for:

• 5+ years of experience in Java development, preferably in FinTech.
• Strong experience with Java and Spring Framework.
• Solid understanding of microservices architecture and design patterns.
• Proficient in SQL (Oracle, PostgreSQL).
• AWS experience and Python knowledge are a plus.
• Ability to work independently and take ownership of technical and architectural decisions.
• Bachelor's degree or higher required.
• Upper-intermediate English level or higher.

What we offer:

• Competitive compensation depending on experience and skills.
• Regular assessments and salary reviews.
• Paid personal days.
• Mental health support program.
• Partial gym compensation.
• Language classes.
• Flexible working schedule.

Project Description:

One of the world's largest providers of products and services to the energy industry has a need to develop and support enterprise information system in Oil & Gas domain.

Product being developed is a cloud solution for interpretation of geological and geophysical data. Project is based on SCRUM methodology.

Our project is stable, long-term and constantly adopts new technologies such as newest Java and Eclipse RCP versions, cloud and GPU computing, microservices architecture and other innovative frameworks.

Work supposes close cooperation with Customer team located in Houston and following Agile principles.

Our team is senior, supportive and friendly.

Responsibilities:

• Collaborate closely with geophysicists, data scientists, and software engineers to translate scientific domain requirements into robust on-prem or Cloud software solutions.

• Design, develop, and maintain high-performance applications for geophysical and geological data analysis, interpretation and visualization

• Present architectural designs and technical proposals to the architecture review board.

• Ability to break down development tasks and lay out clear implementation roadmaps.

• Implement and optimize computation algorithms

• Design and develop both thin and thick client applications that interact with cloud-based microservices.

• Ensure high code quality through unit testing, code reviews, security hardening and continuous integration with other domain tools

• Provide technical support and lead user troubleshooting sessions to resolve issues and ensure smooth operation of DSG application.

• Mentor junior developers and actively contribute to architectural and

implementation decisions.

• Embrace Agile/Scrum methodologies, delivering and demonstrating working solutions at the end of each sprint

• Stay current with emerging technologies and trends in geophysical computing and software development.

Mandatory Skills Description:

At least 5-10 years of experience

GIS Java Eclipse

ESRI ArcGIS Runtime

ESRI Services and Authentication

Nice-to-Have Skills Description:

DSG experience

Oil and Gas experience is preferred but not mandatory

Languages:

English: B2 Upper Intermediate

PioGroup Software is a team of professionals passionate about building reliable digital products. We are looking for an experienced Senior Blockchain Engineer with strong production experience working with the Bitcoin protocol and Bitcoin wallet/custody infrastructure.

The main focus of the role is developing and maintaining Bitcoin wallet infrastructure, including UTXO management, transaction construction and signing, PSBT, SegWit, multi-signature flows, fee management, and transaction lifecycle handling.

For this position, hands-on production experience specifically with the Bitcoin protocol is essential. General blockchain or Web3 experience alone is not sufficient.

Requirements

• 3+ years of production experience with Bitcoin / BTC infrastructure.
• Hands-on experience with Bitcoin-based protocols, UTXO model, PSBT, and BIP standards.
• Strong experience with Java, Spring Boot, and SQL.
• Experience working with production wallet or custody infrastructure.
• Good understanding of TDD and/or BDD practices.
• Familiarity with Domain-Driven Design principles.
• Experience working in a monorepo environment with shared libraries and coordinated CI/CD pipelines.
• Professional written and spoken English.
• Proactive communication and ability to raise blockers, technical concerns, and cross-team dependencies.

Bitcoin Protocol Expertise

We expect strong practical knowledge of:

• PSBT and BIP-174.
• UTXO management and coin selection.
• SegWit transaction structures.
• Bitcoin script types and descriptor formats.
• HD wallets and derivation paths.
• BIP-48 and BIP-67.
• P2WSH and multi-signature transaction flows.
• PSBT combination, signing, and finalisation.
• Witness data and BIP-143.
• DER signature encoding, low-S enforcement, and sighash types.
• UTXO indexing and balance calculation.
• Address discovery, gap limits, change address allocation, and address reuse prevention.

Transaction Lifecycle & Fee Management

Production experience with:

• Mempool monitoring.
• Fee estimation and fee-rate prediction.
• RBF (Replace-By-Fee).
• CPFP (Child-Pays-For-Parent).
• Stuck transaction detection.
• Transaction replacement and rebroadcasting.
• Confirmation monitoring.
• Double-spend detection.
• UTXO consolidation during low-fee periods.

Candidates should also clearly understand the operational difference between a transaction being:

• Broadcast.
• Accepted into the mempool.
• Confirmed.
• Confirmed at depth N.

A strong understanding of Bitcoin probabilistic finality, dust limits, fee spikes during network congestion, and the behaviour of unconfirmed transactions is also required.

Responsibilities

• Develop and maintain Bitcoin wallet infrastructure.
• Manage UTXOs and wallet balances.
• Construct Bitcoin transactions.
• Work with PSBT and SegWit.
• Implement multi-signature transaction flows.
• Handle fee estimation and fee bumping using RBF and CPFP.
• Monitor mempool activity and transaction lifecycle.
• Implement deposit detection and address-level balance monitoring.
• Support wallet recovery and descriptor-based address discovery.
• Participate in technical design and architecture decisions.
• Collaborate with other engineering squads and shared platform components.

Nice to Have

• Experience with multiple blockchain protocols.
• Experience with institutional-grade custody or wallet platforms.
• Experience working with systems processing high volumes of Bitcoin transactions.

Important: we are specifically looking for candidates with documented commercial experience working with the Bitcoin protocol, including UTXO management, PSBT, SegWit, BIP standards, and the Bitcoin transaction lifecycle. Testnet-only, personal wallet, or exclusively Ethereum/Web3 experience will not be sufficient for this role.

Our Mission and Vision

At Solidgate, our mission is clear: to empower outstanding entrepreneurs to build exceptional internet companies. We exist to fuel the builders — the ones shaping the digital economy — with the financial infrastructure they deserve. To achieve that, we're on a bold path: to become the #1 payments orchestration platform in the world.

We believe the future of payments is shaped by people who think big, take ownership, and bring curiosity and drive to everything they do. That's exactly the kind of teammates we want on board.

Solidgate is part of Endeavor — a global community of the world's most impactful entrepreneurs. We're proud to be the first payment orchestrator from Europe to join — and to share our expertise within a network of outstanding global companies.

About the Team and Role

You'll join the Core team — the team responsible for the services that sit at the heart of Solidgate's payment processing. Core services define what a payment is, integrate with numerous internal services for correct routing, run antifraud checks, and process payments through providers, covering card payments as well as Apple Pay and Google Pay. This is the critical path for every payment on the platform, so the team's work directly defines the reliability and speed of the whole system.

The team is actively growing new functionality, supporting existing services, working down technical debt, and maintaining an SLO of 99.99%+ across all of its services. The stack is built around high-load, low-latency requirements: a microservices architecture with Kotlin as the primary language, Protobuf RPC over Buf/Connect, PostgreSQL as the main database, and Kafka for asynchronous processing, with fully automated production deployments and an advanced monitoring and observability setup. Infrastructure is continuously improved by a dedicated platform team, with IaC ensuring transparent, reproducible, and scalable management.

Your team — Product Manager, Tech Lead (Backend), three Backend Software Engineers (Senior), one Frontend Software Engineer (Middle), AQA Engineer, and System Analyst.

What you'll own

Your focus will be on:

• taking part in product decisions across the full development lifecycle
• designing and developing backend functionality for our products
• collaborating with other teams to build reliable solutions for payment processing
• improving the performance, scalability, quality, and reliability of our systems

You'll grow from feature-level tasks toward owning a dedicated service or domain, taking part in the team's design and technical decisions.

You're a great fit if you have

• 3+ years of experience with Java
• Confident hands-on experience with SQL databases (PostgreSQL/MySQL)
• Experience designing reliable, scalable systems
• Experience with distributed systems
• Experience with cloud environments (AWS/GCP)
• Technical/computer science-related degree
• 2+ years of active hands-on use of AI tools

Nice to have

• Experience with Kotlin
• Fintech experience and experience with high-load, complex systems
• Observability/Alerting tools (Prometheus, Grafana)
• Infrastructure as Code (Terraform)
• Message brokers (Kafka/SQS/RabbitMQ)

Why Solidgate?

High-impact role. You'll work at the very core of our payment processing — the critical path for every transaction, including Apple Pay, Google Pay, and card payments.

Great product. We've built a fintech powerhouse that scales fast. Solidgate isn't just an orchestration player — it's the financial infrastructure for modern Internet businesses. From subscriptions to chargeback management, fraud prevention, and indirect tax — we've got it covered. We hold financial licenses in key regions and are a direct Visa & Mastercard partner and sub-reseller (top 5 globally).

Massive growth opportunity. Solidgate is scaling rapidly — this role will be a career-defining move.

Top-tier tech team. Work alongside our driving force — a proven, results-driven engineering team that delivers.

Modern engineering culture. TBDs, code reviews, solid testing practices, metrics, alerts, and fully automated CI/CD.

💌 The Extras: 30+ days off, unlimited sick leave, free office meals, health coverage, and Apple gear to keep you productive. Courses, conferences, sports and wellness benefits — all designed for ideas, focus, and fun.

Tomorrow's fintech needs your mindset. Come build it with us.

🫂 Know top talent? We're always on the lookout. Refer someone for our role, and if they get hired, there's a bonus waiting for you — simple as that.

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.

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

About Our 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 for the data catalog and enterprise data management layer of a large-scale lakehouse platform — the services that automate data ingestion and autonomously optimize Apache Iceberg tables. You will own features through the full development cycle, from design through deployment, in a multithreaded, distributed environment where scalability, performance, and always-on availability are the baseline expectations.

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

Responsibilities

• Own the full software development cycle — inception, design, development, testing, deployment — for catalog and data-management services
• Build and operate services for automated ingestion and autonomous optimization of Apache Iceberg tables
• Reason about concurrency and parallelization to deliver scalability and performance in multithreaded, distributed systems
• Drive performance tuning and system-efficiency improvements
• Work with Apache Foundation open-source projects, contributing upstream where agreed
• Participate in code and design reviews, upholding a high engineering bar
• Collaborate with product managers, support teams, and solution architects on feature requests and design updates
• Partner with US-based engineering leads on technical decisions

Required Qualifications

• B.S., M.S., or PhD in Computer Science or a related field
• 5+ years of software engineering experience, preferably focused on database systems or related fields
• Strong object-oriented programming skills in Java or C++
• Solid grounding in data structures and algorithms
• Hands-on experience with multithreaded and asynchronous programming patterns for scalable, performant systems
• A passion for engineering quality — zero-downtime upgrades, availability, resiliency, and uptime as first-class concerns
• Comfort with a fast-moving environment; strong ownership; the confidence to defend a technical position and the openness to be mentored
• Comfortable with AI-assisted development workflows — using modern AI tools productively while critically validating their output
• English Upper-Intermediate or higher (B2+) — daily written and verbal communication with a US-based engineering team
• Availability to work EU business hours shifted 2–3 hours later for daily overlap with US West Coast mornings

Desired Skills

• Database internals and query planning
• Distributed systems: concurrency control, data replication, storage systems
• Apache Iceberg or other open table formats (Delta Lake, Hudi)
• Messaging systems: Kafka, NATS, or cloud pub/sub services
• Contributions to open-source data infrastructure (Apache projects especially valued)

Details

• Engagement: Long-term contract
• Location: Europe (EU / EEA / UK), remote
• Working hours: EU business hours, shifted 2–3 hours later for daily overlap with the US West Coast team

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