React Developer – Remote (U.S. Based)

Location: United States – Work from Home
Job Type: Full-Time | Remote

About the Role

A leading provider of financial technology solutions is seeking a talented and experienced React Developer with strong TypeScript skills to help build a next-generation low-latency FX trading platform. This is a unique opportunity to work on cutting-edge systems that power billions of dollars in daily transactions.

As a React Developer, you’ll collaborate closely with backend engineers, product managers, and clients to create high-performance, scalable, and intuitive user interfaces. Your work will directly impact real-time trading operations and data visualization.

Key Responsibilities

• Develop and maintain high-performance frontend applications using React and TypeScript
• Build responsive and intuitive UIs for real-time financial data visualization
• Integrate seamlessly with backend services using REST APIs and Google Protobufs
• Optimize applications for speed, scalability, and maintainability
• Collaborate with cross-functional teams to deliver robust trading solutions

Requirements

• 3+ years of professional experience with modern React frameworks
• Strong proficiency in TypeScript
• Solid understanding of Google Protobufs and REST APIs
• Experience with financial trading systems
• Familiarity with Java and SQL is a plus
• Excellent communication and teamwork skills
• Bachelor’s degree in Computer Science or a related field

About the Company

This organization is an award-winning technology provider specializing in front-office foreign exchange solutions. Their innovative and high-performing trading systems are trusted by global banks, brokers, and investment firms to support billions in daily FX transactions.

Head Of Attack Surface Management

📍 Location: London, UK | 💼 Full-Time |

A leading Global Financial Organisation is seeking a highly skilled and experienced professional to join the team as the Head of Attack Surface Management. This pivotal role involves overseeing and enhancing our cybersecurity posture by effectively managing and reducing the attack surface. This is a newly established function, offering you the unique chance to build and lead a critical area from the ground up.

Responsibilities:

• Develop a comprehensive ASM strategy aligned with the institution's security goals and regulatory requirements whilst establishing policies and procedures for managing the attack surface
• Select and implement industry ASM tools and technologies bespoke to the clients infrastructure
• Enhance and mature vulnerability assurance and attack surface management to drive improvements and reduce operational risk exposure
• Continually review the vulnerability management and attack surface toolset, ensuring capabilities reduce risks exposed
• Develop and own the approach to secure development, ensuring relevant standards and controls are implemented and applied throughout the lifecycle of projects

Requirements:

• Extensive experience in cybersecurity, particularly in managing vulnerabilities and reducing attack surfaces
• In-depth knowledge of regulatory and industry standards related to cybersecurity.
• Proficiency in security testing methodologies and tools
• Strong ability to develop and implement secure development practices
• Relevant qualifications such as CISSP, CRISC, SEC599, SEC565 are beneficial

If you or anyone you know is interested in this role, APPLY BELOW or feel free to reach out on Matthew.Dobree-Carey@caspianone.co.uk

Senior Java Software Engineer – Calypso Trading Platform
Location: London (Hybrid – 2 days per week in-office)

We are working with a global financial institution that is expanding its engineering team in London. They are seeking experienced Senior Java Developers to enhance and extend a key trading and risk platform based on Calypso, used across multiple asset classes and business lines.

This is a hands-on backend development role, ideal for someone who enjoys working on complex systems in a real-time financial environment. The focus is on building scalable, high-performance Java applications that support trading, risk management, settlements, and accounting.

Role Overview:

• You’ll work as part of a cross-regional team (London, Dublin, North America), contributing to the long-term evolution of a strategic Calypso-based platform. While Calypso is the core vendor system, there is an extensive ecosystem of internally built services and custom integrations that require strong software engineering skills.
• You’ll have the opportunity to work on feature enhancements, platform integration, and broader architectural improvements – with visibility across trading and operations.

What You’ll Do:

• Develop and maintain Java-based services that extend and integrate with Calypso
• Collaborate on design decisions and contribute to platform strategy
• Improve performance, scalability, and resilience of trading systems
• Participate in capacity planning, testing, and deployment pipelines
• Work closely with other technology and business teams across global regions

Core Tech & Tools:

• Java 8+
• Oracle (SQL)
• Linux (RedHat)
• Messaging: IBM MQ, Kafka, Solace
• CI/CD: Jenkins
• Monitoring: Splunk

What We’re Looking For:

• 7+ years of Java development experience in complex, distributed systems
• Strong understanding of multi-threading, performance tuning, JVM internals
• Experience working with relational databases, ideally Oracle
• Familiarity with messaging systems (MQ, Kafka, Solace)
• Prior experience working with or integrating Calypso (2–3 years minimum)

Nice to Have:

• Experience in capital markets, derivatives, or trade lifecycle management
• DevOps experience or familiarity with build/test/release pipelines
• Exposure to large-scale platform integration projects
• Comfort working in a regulated, globally distributed environment

Why Apply?

• Be part of a growing London-based team with global impact
• Work on a mission-critical platform at the heart of trading and risk
• Java-first engineering culture – strong tech matters more than deep finance
• Flexible on notice periods (up to 3 months considered)
• Opportunity to contribute to both design and hands-on build work
• This is a unique chance for skilled Java engineers to get under the hood of Calypso and help shape a platform used globally for high-value trading and financial operations.

About the Role

We are seeking an experienced and driven Rates eTrading System Engineer to join our high-performance technology team in London. In this pivotal role, you’ll combine technical expertise with strong business acumen to ensure the reliability, performance, and scalability of our trading platforms. You’ll work side-by-side with front-office traders and developers, acting as a bridge between business and technology in a dynamic, high-pressure environment.

Key Responsibilities

• Ensure the availability, performance, and scalability of systems through proactive monitoring, maintenance, and capacity planning.

• Lead incident response and root cause analysis, implementing long-term fixes to prevent recurrence.

• Design and develop tools/scripts to automate operational tasks, improving system efficiency and reducing manual workload.

• Optimise system performance and resource usage by identifying and resolving bottlenecks.

• Work closely with development teams to integrate site reliability and performance best practices into the full software lifecycle.

• Stay up to date with industry trends and contribute to internal technology communities.

• Provide technical leadership and guidance, mentoring junior team members and influencing decision-making.

What We’re Looking For

• Deep expertise in eTrading systems, ideally within Rates, though experience in other asset classes is also considered.

• Proven ability to work directly on the trade floor, confidently interfacing with traders and developers.

• Strong Unix/Linux command-line skills.

• Demonstrated ability to manage a prioritised book of work and contribute to product enhancement and issue remediation.

Preferred Skills

• Familiarity with monitoring and observability tools such as Elastic, Geneos ITRS, and Grafana.

• Understanding of systems architecture and production log investigation.

• Track record of delivering solutions under pressure in a real-time trading environment.

About You

You’re a technically sharp, business-facing engineer who thrives in fast-paced environments. You enjoy solving complex problems, speaking the language of both trading and technology, and driving operational excellence in mission-critical systems.

UX Designer - Multi-Asset Financial Platform

Poland (Remote/Hybrid)
Type: Contract B2B
Rate: up to 1800/day PLN
Duration: 6 months rolling contract

About the Company

Join a leading financial technology company with a mature, multi-asset trading platform serving over 500 stakeholders globally. Our platform supports equities, fixed income, loans, and bespoke technical applications with 100+ built applications used by front office teams, loan traders, and market traders across retail, wealth, and institutional segments.

The Opportunity
We're seeking a passionate UX Designer to join our centralized design team and transform the user experience of our established 5-year-old platform. This is a unique opportunity to make a significant impact on a functional system that's ready for a comprehensive UX overhaul.

What You'll Do

Lead UX Transformation: Spearhead the comprehensive redesign of our multi-asset platform's user experience, focusing on aesthetics, workflows, and usability
Collaborate Cross-Functionally: Work closely with our development team, scrum masters, and various product squads to implement design improvements
Identify & Solve Pain Points: Conduct user research, analyze workflows, and gather feedback to pinpoint areas needing enhancement
Design System Development: Create and maintain consistent theming, styling, and branding across 100+ applications
Stakeholder Engagement: Partner with diverse user groups including traders, front office staff, and wealth management teams

What We're Looking For

Essential Skills:

Expert proficiency in Figma (mandatory)
Strong portfolio demonstrating UX/UI design expertise
Experience with workflow optimization and user journey mapping
Proven ability to identify and solve complex user experience challenges

Preferred Qualifications:

Financial services background - understanding of trading platforms, financial workflows, and the importance of reducing clicks and optimizing critical information display
Experience designing for complex, multi-application platforms
Knowledge of design systems and component libraries
Understanding of technical constraints in large-scale applications

Team Structure
You'll be part of our centralized UX team, spending 80% of your time with our core squad including product managers, scrum masters, UX developers, and backend engineers. You'll also collaborate with specialized squads focusing on platform management, equities, loans, cash segments, and wealth management.

Why Join Us?

Meaningful Impact: Transform the daily experience of hundreds of financial professionals
Established Platform: Work with a mature, successful product with proven market fit
Growth Opportunity: Shape the future of financial technology UX
Collaborative Environment: Join a team that values expertise, innovation, and professional development
Stability: Approved budget and long-term commitment to UX excellence

Role: Core Java Developer
Location: Remote – US-based preferred (ideally EST)
Salary: Flexible, based on experience

About the Role

A specialist trading technology firm is looking for a Backend Java Engineer to help build and optimise its high-performance FX trading systems. This role suits someone with a strong handle on core Java who enjoys working close to the metal—performance matters, and every microsecond counts.

You’ll be involved in both greenfield projects and enhancements to legacy systems, working within a close-knit team of experienced engineers. There’s a strong emphasis on autonomy, low-latency optimisation, and getting things done without layers of process.

What You’ll Work On

• Enhancing and maintaining high-throughput, real-time trading applications.
• Building new features with a strong focus on performance, scalability, and system integrity.
• Diagnosing and resolving performance issues (e.g. GC tuning, threading, latency spikes).
• Writing robust unit tests and contributing to code quality and peer reviews.
• Occasionally touching front-end elements (React/TypeScript), but mainly from a backend understanding perspective.
• Operating within a fast-paced, latency-sensitive trading environment where backend efficiency is king.

What We’re Looking For

Essential Technical Skills

• Strong core Java skills with 3+ years of hands-on backend experience.
• Understanding of threading, memory usage, collections, and performance tuning.
• Experience working on systems where throughput and latency are critical.
• Familiarity with messaging protocols and event-driven architecture.
• Desirable Technical Skills
• Exposure to technologies such as FIX, Protobuf, PostgreSQL, Maven, Jenkins.
• Some familiarity with React or TypeScript is helpful but not essential.
• Previous experience in financial markets or trading systems is a big plus.
• Experience working in multi-threaded, low-latency environments.

Soft Skills

• Able to work independently and remotely within a lean, delivery-focused team.
• Strong communication skills—written and verbal.
• Previous experience in fast-paced environments such as fintech or trading desirable.

Why Join?

• 100% remote with flexibility—no clock watching, just high standards and ownership.
• Work on high-impact systems used by major financial institutions.
• Small team, flat hierarchy, and a strong culture of collaboration (plus regular meetups and socials).
• Real opportunity to work on systems where microseconds matter.
•  

Interview Process

• Introductory call
• Three technical interviews (coding-heavy)
• Final discussion with senior leadership

Senior UI Developer (React/TypeScript)
Contract Type: B2B Contract
Duration: 6 month rolling contract with at least 2 years of work secured
Rate: Up to 2,300 PLN per day (depending on experience and seniority)
Location: Remote in Poland (only 1 day per month in-office initially)

About the Opportunity

Join a new team being established in Poland as part of an international expansion by a leading global financial institution. This is a rare opportunity to work on an in-house built pricing, execution, and trade processing platform for financial markets as part of a global development team.

Key Responsibilities

Work across all delivery stages from requirements gathering to post-release support
Own and collaborate on technical design decisions
Break down large projects into manageable tasks and coordinate solution delivery
Build new functionality within existing coding patterns and architecture
Coach other developers and participate in hiring processes
Develop complex, real-time event-driven multi-modular single page applications

Essential Requirements

7+ years of relevant development experience
Expert-level skills in React, Redux, RxJS, NPM/Yarn, webpack, CSS, HTML
Experience with CI/CD pipelines (e.g., Azure DevOps)
Proven experience building complex, real-time (event-driven) multi-modular single page applications
Strong software design principles and knowledge of design patterns
Ability to optimize performance of latency-sensitive systems
Full-stack development capability (preferably with Java backend experience)
Fluent English communication skills

Preferred Qualifications

Financial markets domain knowledge
Experience with TypeScript in enterprise environments
Background in high-performance trading systems
Previous experience in international banking or financial services

What We Offer

Competitive daily rate up to 2,300 PLN
Long-term contract security with 2+ years of work already confirmed
Remote-first working arrangement with minimal office requirements
Opportunity to work on cutting-edge financial technology
International collaboration with global teams
Professional development through coaching and mentoring opportunities

Ideal Candidate Profile

You are a seasoned UI developer with deep expertise in React and modern JavaScript frameworks. You thrive in fast-paced environments where performance and reliability are critical. You have experience with real-time systems and understand the unique challenges of building user interfaces for financial applications.

Senior Data Engineer - Financial Services
Contract Type: B2B Contract
Rate: Up to 1,800 PLN per dayLocation: Krakow or Wroclaw (Hybrid working)

About the Role

We are seeking a Senior Data Engineer to join our team for end-to-end development lifecycle of data engineering projects. This role involves transforming data into business insights, developing automated solutions, and leading the architecture of cloud-based data lakehouse solutions. The position combines hands-on technical work with senior leadership responsibilities in big data and data lake environments.

Key Responsibilities - First 3-6 Months

Lead data engineering project development from concept to deployment
Build and optimize ETL pipelines using Azure Databricks (Spark, Python, SQL)
Implement data quality, security, and compliance measures
Collaborate with cross-functional teams on cloud migration initiatives
Establish observability and monitoring for production systems
Contribute to architectural decisions for lakehouse implementation
Mentor team members and codify best practices

Essential Technical Skills

Expert knowledge of ETL using Azure Databricks (Spark, Spark SQL, Python, SQL)
Strong Databricks, SQL and Python skills
Solid understanding of data modelling and data warehousing principles
Lakehouse architecture knowledge
Understanding of ETL/ELT design patterns
Software development lifecycle expertise

Preferred Technical Skills

Columnar and time series data design patterns
Performance tuning techniques
Infrastructure as Code and scripting languages
Information Security principles for data handling

Essential Business Skills

Strong problem solving and analytical skills
Ability to clearly communicate complex solutions
Experience working in Agile methodologies (SCRUM, Kanban)
Understanding of client needs representation

Preferred Business Skills

Financial services/investment banking domain knowledge
Enterprise-wide problem solving experience

Essential Personal Qualities

Proven team player with strong leadership skills
Collaborative approach across business units, teams and regions
Continuous learning mindset
Ability to influence architectural and design principles

Team & Culture

You'll be joining a dedicated team of professionals building next-generation platforms. Our culture emphasizes continuous learning, collaboration across regions, and innovation in financial technology solutions.
Interview Process
Two-stage process including technical and high-level interviews.