Senior kdb+ Developer - BestX

We are seeking an experienced Senior kdb+ Developer to join the BestX engineering team. In this role, you will design, build, and optimise high-performance data platforms using kdb+, supporting BestX's multi-asset analytics capabilities.

The ideal candidate brings deep expertise in kdb+ tick architectures, large-scale performance tuning, and works closely with quantitative and engineering teams to deliver robust, efficient, and maintainable solutions.
Key Responsibilities

• Design and develop key components of BestX's multi-asset analytics platform.
• Architect, build, and maintain kdb+ tick systems, with strong consideration for data organisation, schema design, and architectural trade-offs.
• Develop and operate systems that process large-scale, high-frequency datasets, ensuring low latency, high throughput, and efficient memory utilisation.
• Analyse and optimise q queries, data models, and ingestion pipelines for both real-time and historical workloads.
• Apply modern Agile development practices across cloud-based, server-side, and database-driven systems.
• Build a strong understanding of Transaction Cost Analysis (TCA) and key regulatory benchmarks required for MiFID and MiFIR.
• Take full ownership of deliverables, driving work through from design to production.
• Establish and promote best practices, clean code standards, and sound design patterns.
• Act as a change agent, continuously improving engineering standards and ways of working.
• Champion Test-Driven Development and "shift-left" practices to support effective CI/CD pipelines.

Core (Must-Have) Skills and Experience

• 5+ years of hands-on kdb+ development experience.
• Strong expertise in kdb+/q and Python.
• Proficiency with modern data science toolchains, including Jupyter, pandas, NumPy, scikit-learn, with applied machine-learning experience.
• Solid understanding of parallel computing frameworks such as Slurm or equivalent technologies.
• Strong background in quantitative analysis, including mathematical modelling, statistics, regression, and probability theory.
• Bachelor's or Master's degree in Computer Science, Mathematics, Statistics, or a related STEM discipline from a top-ranked university.
• Hands-on experience with AWS and/or other modern cloud-based infrastructure.

Nice-to-Have Skills

• Domain knowledge in FX, Fixed Income, Equities, or Equity Derivatives.
• Additional expertise with kdb+ in complex, production-scale environments.
• Exposure to modern JavaScript build toolchains, including Node.js, npm, Rush, Yarn, Webpack, Babel, and Cypress.

About State Street & BestX

State Street is a global financial services leader, combining scale, resilience, and advanced technology to support institutional investors worldwide. Through investment servicing, trading, data, and analytics, we build mission-critical platforms that operate at the heart of global financial markets.

BestX , part of State Street's Global Markets and GlobalLink ecosystem, is the industry-standard, multi-asset Transaction Cost Analysis (TCA) platform . Built as a high-performance analytics platform, BestX processes over one billion market data updates per day , delivering independent, venue-agnostic insights across FX, fixed income, and equities.

BestX has been recognised globally for its technology and impact, including:

• World's Best Provider of TCA Solutions - Euromoney Markets Awards 2025
• Best Transaction Cost Analysis Solution - WatersTechnology Asia Awards 2025
• World's Best New FX Product/Platform for BestXecutor - Euromoney 2025

BestX and BestXecutor embed advanced analytics directly into trading workflows, spanning pre-trade decisioning through post-trade validation, helping clients improve execution quality and meet evolving regulatory requirements at scale.

At State Street, you'll work on complex, high-performance systems alongside leading engineers, quants, and product teams-shaping the future of execution analytics and global market infrastructure in an inclusive, supportive environment

Salary Range:
$125,000 - $226,250 Annual

The range quoted above applies to the role in the primary location specified. If the candidate would ultimately work outside of the primary location above, the applicable range could differ.

Employees are eligible to participate in State Street's comprehensive benefits program, which includes: our retirement savings plan (401K) with company match; insurance coverage including basic life, medical, dental, vision, long-term disability, and other optional additional coverages; paid-time off including vacation, sick leave, short term disability, and family care responsibilities; access to our Employee Assistance Program; incentive compensation including eligibility for annual performance-based awards (excluding certain sales roles subject to sales incentive plans); and, eligibility for certain tax advantaged savings plans.

For a full overview, visit https://hrportal.ehr.com/statestreet/Home.

About State Street

Across the globe, institutional investors rely on us to help them manage risk, respond to challenges, and drive performance and profitability. We keep our clients at the heart of everything we do, and smart, engaged employees are essential to our continued success.

We are committed to fostering an environment where every employee feels valued and empowered to reach their full potential. As an essential partner in our shared success, you'll benefit from inclusive development opportunities, flexible work-life support, paid volunteer days, and vibrant employee networks that keep you connected to what matters most. Join us in shaping the future.

As an Equal Opportunity Employer, we consider all qualified applicants for all positions without regard to race, creed, color, religion, national origin, ancestry, ethnicity, age, disability, genetic information, sex, sexual orientation, gender identity or expression, citizenship, marital status, domestic partnership or civil union status, familial status, military and veteran status, and other characteristics protected by applicable law.

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It is unlawful in Massachusetts to require or administer a lie detector test as a condition of employment or continued employment. An employer who violates this law shall be subject to criminal penalties and civil liability.