Senior Software Engineer - JVM Language Clients

About ClickHouse: ClickHouse is a premier, internationally recognized database infrastructure juggernaut, real-time analytics market leader, and Forbes Cloud 100 technology titan operating on an absolute mission to protect, optimize, and transform how global enterprises manage, store, and utilize data at hyper-scale. Powering mission-critical analytical workflows, real-time observability grids, and enterprise AI data pipelines for the world’s most sophisticated digital innovators—including Meta, Cursor, Tesla, Capital One, Airwallex, and Sony—ClickHouse maintains breakneck commercial velocity, highlighted by consecutive triple-digit ARR growth and backed by a monumental $400M Series D financing round. Driven by a high-performance, developer-first corporate philosophy that prizes technical excellence, pragmatic problem-solving, and open-source collaboration, the organization provides high-agency engineering leaders with an uncompromised remote canvas to leverage cutting-edge systems, manipulate byte-level network protocols, and deploy robust, low-latency database architectures safely across Spain.

Position Overview

We are seeking a highly analytical, detail-obsessed, and systems-minded Senior Software Engineer - JVM Language Clients to join our core centralized Integrations Ecosystem organization in a full-time remote capacity open to qualified technical builders resident anywhere in Spain. Operating as the technical owner and primary strategic architect behind ClickHouse’s official Java client and JDBC driver, you will step up to claim true individual operational and strategic accountability for the foundational communication layer that our internal Connectors team and a massive global network of third-party frameworks rely on every single second. Shifting completely away from routine application layer building, standard web interface modifications, minor standalone template adjustments, or disconnected utility typing, you will run an active low-level database performance and system design laboratory—optimizing low-level drivers, configuring data framework integrations, and maximizing throughput metrics. This position requires a database systems or stream processing veteran with 5+ years of craft depth who architects high-throughput network clients fluidly natively using Backend mechanics, engineers automated testing or regression blocks cleanly natively leveraging Python or alternative script automation tools, and commands JVM concurrency patterns confidently under open-source community standards.

Key Responsibilities

• End-to-End JVM Driver Ownership: Serve as the principal technical owner for the ClickHouse Java client and JDBC driver, directing its architectural roadmap, public API design patterns, and release engineering pipelines cleanly natively utilizing Backend methodologies.
• Low-Level Performance Optimization: Drive high-impact throughput and latency enhancements across the client and ClickHouse server, optimizing data layouts down to the level of bytes on the wire.
• Internal and External Client Interlock: Partner day-to-day with our core Connectors team as an embedded customer, ensuring the underlying driver architecture natively supports official ingestion bridges for Apache Kafka, Spark, and Flink.
• Open-Source Ecosystem Engagement: Engage transparently with the global open-source data infrastructure community, handling public issue queues, conducting public code reviews, and aligning maps on external data visualization platforms.
• JVM Concurrency and Resource Governance: Design and optimize high-concurrency components, configuring executor pools, managing reactive streams, handling backpressure thresholds, and tuning connection pools to prevent runtime failure modes.
• Memory Model and Profiling Audits: Profile runtime client environments continuously, executing JVM memory adjustments, garbage collection (GC) tuning, and heap allocations to protect application reliability.
• Technical Documentation and RFCs: Write, defend, and iterate technical design documents, Requests for Comments (RFCs), and detailed architectural proposals to guide collaborative engineering investments.
• AI-Assisted Development Integration: Incorporate modern AI development tools (such as Claude Code, Cursor, or GitHub Copilot) into development processes with a strict, high-judgment independent code review perspective.

Required Skills & Qualifications

• A minimum of 5 years of verified professional software engineering history, with a powerful, demonstrable focus on data-intensive systems (such as database drivers, SDKs, complex data ingestion pipelines, CDC tools, streaming meshes, or OLAP infrastructure).
• Expert-tier capability optimizing low-level backend abstractions, designing reusable developer tools, and building thread-safe library architectures natively utilizing Backend parameters.
• Practical operational familiarity writing regression frameworks, automating integration diagnostics, and parsing systemic trace outputs natively using Python or adjacent language structures.
• Deep, comprehensive expertise inside the Java platform and the JVM runtime environment, highlighting deep familiarity with memory alignment, GC internals, profiling suites, and network I/O layers.
• Proven technical history building, releasing, or substantially extending a widely adopted software library or software development kit (SDK) where API design backward compatibility is critical.
• Strong, uncompromised grasp of database fundamentals, encompassing structural SQL query execution, analytical OLAP workloads, and column-store concepts.
• Outstanding written and scannable technical communication attributes in business-fluent English, enabling seamless coordination across a globally distributed team through engineering documentation.
• Location Context: Position open to qualified software engineers based permanently and resident within the borders of Spain to operate under a 100% remote work-from-home layout.

Preferred Strategic Indicators (Nice to Have)

• Working knowledge of JDBC internals, Arrow Flight SQL, ADBC, or columnar data models (such as Apache Arrow specifications).
• Prior code contributions to open-source data infrastructure systems (such as Apache Kafka, Flink, Spark, dbt, Debezium, or Iceberg platforms).
• Experience engineering customized network wire protocols or contributing to high-concurrency client-server network applications.

What We Offer

• Vetted Global Data Sector Salaried Blueprint: A highly competitive full-time baseline annual corporate base salary package calibrated precisely to evaluate your JVM authority and system craftsmanship, paired with an impactful equity stake through lucrative corporate stock options.
• The exceptional professional canvas to claim absolute technical code authorship over the official Java driver architectures power-routing data queries for thousands of global enterprises.
• Profound work-from-home remote parameters offering a 100% remote layout within Spain, complete scheduling trust, and zero physical geographic office commuting friction out of any province.
• Immediate baseline access to a premium group healthcare protection matrix, featuring robust employer premium contributions to ensure comprehensive health coverage.
• Access to progressive lifestyle and wealth accumulation systems, including a dedicated $500 USD Home Office setup allowance to maximize your remote workspace configuration, generous flexible time-off policies, and direct corporate enrollment into our elite Global Gatherings company-wide offsites to foster deep in-person technical synergy.