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Agent guide: [/agents.md](https://www.wearedevelopers.com/agents.md). --- # Senior Java/Kotlin Engineer - **Company:** ApTask - **Location:** Jersey City, NJ, United States - **Experience:** Expert - **Salary:** $180,000.0 - $220,000.0 - **Contract:** Permanent contract - **Skills:** Java (Programming Language), Artificial Intelligence, Algorithmic Trading, Data Analysis, Big Data, Cloud Computing, Continuous Integration, Data Integrity, DevOps, Java Virtual Machine (JVM), Machine Learning, MongoDB, OpenShift, Performance Tuning, Software Engineering, Transact-SQL, Trunk-based Development, Multithreading, Test-Driven Development (TDD), Grafana, Kotlin, Event Driven Architecture, Kubernetes, Apache Kafka, Event Sourcing, Code Restructuring, Serverless Computing, Legacy Systems - **Published:** November 2, 2026 - **Apply:** https://www.careerbuilder.com/job-details/senior-java-kotlin-engineer-jersey-city-nj--b904ad4c-b86b-4456-9caa-290618670bff ## About the Role Java, Software Engineering, Kotlin, Machine Learning, DevOps, Fortune 1000 Customers, Data Analysis, Process Improvement, Cloud Computing, Big Data, * Expert-level Java, with Kotlin experience or a clear appetite for it (enterprise-grade systems, multi-threading, performance). * Practical experience designing and building event-driven systems on message-passing and event-sourcing patterns, including failure handling, ordering guarantees and replay semantics. * Test-Driven Development as a practice, not an aspiration: you own quality end-to-end, you design for testability, and you can demonstrate it through how you approach a problem (this is assessed at interview). * Hands-on experience in or alongside a capital markets trading or post-trade environment: the trade lifecycle, trade booking and position management, and post-trade operations such as cashflow calculation, settlement and wires, client reporting, and accounting principles. You should be able to back this up with concrete examples, not high-level familiarity. * A track record in genuine iterative delivery incl. short feedback loops, trunk-based development, CI/CD, and regular zero-downtime production releases. No waterfall projects labelled as agile. * Proven ability to analyse, refactor and modernise large-scale legacy systems while maintaining stability. * Senior-level autonomy: you contribute to design discussions, push back constructively on technical decisions, and operate with minimal supervision in a complex production environment. * Bachelor s Degree in Compute Science or similar major. Would be a plus: * Understanding of Prime Brokerage, Synthetic (Swap) or Cash Equity operational flows. This is a significant advantage. * Familiarity with corporate actions, regulatory reporting obligations (e.g. 871(m), EMIR, MiFID), and integrating with risk/valuation systems in an equities context. * Strong SQL Server depth: T-SQL, schema design, performance tuning and complex data models in high-transaction environments. * Kafka (or comparable event-streaming platforms) at scale, and MongoDB. * Kubernetes/OpenShift deployment and cloud-native operational practices, with observability via OpenTelemetry, ELK and Grafana. * Demonstrated AI-first development experience: agentic coding workflows for legacy analysis, refactoring and test generation, with a clear-eyed view of where the tools help and where they don t. ## Description * We are looking for a Senior Java/Kotlin Engineer to work with our client - Tier 1 investment bank on its Equity Accelerator program, a multi-year strategic initiative to modernize the Prime Finance Equities platform. * The program is re-engineering core trading systems, building new data and market-expansion platforms, and launching advanced client features such as cross-margining and credit financing, replacing legacy architecture with event-driven, cloud-native systems designed for institutional-grade stability, throughput and extensibility. * This is not a greenfield build. * You will work directly within a complex, financially significant production system, critically assessing system behavior and data integrity in dynamic market environments, contributing to architectural decisions, and operating with a high degree of autonomy within an experienced engineering group. * This is not general-purpose Java delivery: the domain complexity and the engineering standards applied by the internal team demand engineers with real depth. Essential Functions: * Re-engineering core trading and post-trade systems into event-driven, cloud-native services on the JVM (Java and Kotlin). * Modernising legacy components while keeping a live, financially significant platform stable. * Building the new data and market-expansion platforms that underpin the programme, and the plumbing for advanced client features such as cross-margining and credit financing. * Designing for the realities of event-driven systems: failure handling, ordering guarantees, replay semantics, and data integrity under market pressure. * Practising TDD and shift-left testing as the default. Local-first testing with containerised dependencies, fast feedback loops, and owning the quality of your deliverables end-to-end rather than handing it to a QA group. * Delivering iteratively: trunk-based development, CI/CD, and frequent (weekly or better) production releases during business hours with no service interruption. * Engaging directly with business stakeholders and upstream/downstream teams to build your own domain knowledge, rather than relying on Business Analysts to hold it for you. * Using AI-assisted and agentic development tooling as a genuine accelerator for analysis of legacy code, test generation, prototyping and refactoring.