Senior Product Engineer

About the role

You will lead cross-functional delivery by defining system architecture and designing solutions that turn complex debt market requirements into production-ready services. You will build proof of concepts, implement APIs, and automate data processing to enable new platform capabilities. You will operate as a senior IC, mentoring junior developers and guiding infrastructure decisions that shape the 9fin platform. You will play a key role in early research and experimentation, evaluating emerging technologies to inform future features and products. You will continuously refine the codebase by automating manual steps, refactoring legacy components, and documenting critical workflows for long-term maintainability. You will bridge technical and non-technical stakeholders by explaining intricate projects in clear terms to product, legal, and editorial teams. Your work will directly influence how global banks, asset managers, and advisors access and interact with the largest asset class in financial markets.

Key facts

What you'll do

• Lead project execution from discovery through delivery, owning requirements translation, system design, and implementation of APIs, data processing, and automation for the 9fin platform.
• Develop and maintain backend services and web applications using modern tools and frameworks that power 9fin's financial data, access control, and workflow automation.
• Act as a senior technical contributor in project teams, conducting code reviews, mentoring developers, and guiding early-stage research and experimentation with new technologies.
• Continuously improve the 9fin codebase by identifying opportunities to automate, refactor, and document changes where they will have the greatest impact on quality and efficiency.
• Navigate very diverse web platforms that involve complex financial data modelling, granular access control business logic, environmental and energy data capture, and integration of ML/AI prediction services.
• Collaborate across cross-functional teams that include domain experts from 9fin finance, legal, and editorial to ensure the highest quality information is surfaced in engineering outputs.
• Strengthen developer experience by leveraging managed automated preview environments, feature flags, and well-maintained non-production setups to iterate quickly and safely.
• Build and maintain integrations with data sources and services across a platform handling over $145 trillion in debt markets, ensuring reliability, scalability, and performance.
• Translate ambiguous product requirements into technical specifications and work independently to design, implement, test, and deploy features from idea through production.
• Contribute to architectural decisions that balance fast delivery with long-term maintainability, cost efficiency, and security in a heavily regulated industry.
• Support the rollout of new features to institutional clients by working closely with product managers to validate functionality and usability in real-world workflows.
• Write clean, testable, and well-documented code that aligns with the platform's standards and enables other engineers to build on your work with minimal friction.
• Participate in on-call rotations and incident response when necessary to resolve production issues and maintain high availability for critical market data flows.
• Champion best practices in version control, CI/CD pipelines, and observability to keep the platform resilient as it scales globally.

Requirements

• Have experience operating as a Senior IC Engineer, leading systems design and infrastructure discussions, mentoring more junior team members, and scoping work within cross-functional product teams.
• Be comfortable moving between frontend and backend work, picking the right tool for the problem rather than specializing in a single area.
• Demonstrate strong knowledge of modern JavaScript/TypeScript and frameworks such as React, alongside experience building scalable backend services and APIs.
• Be comfortable leveraging modern AI-assisted development tools such as Cursor, Claude, ChatGPT, and GitHub Copilot to improve productivity while maintaining high engineering quality.
• Have a strong product mindset with an eye for user experience, working closely with designers and product managers to craft intuitive, polished interfaces.
• Be able to independently own features from idea through design, implementation, deployment, and iteration without constant supervision.
• Possess strong system design and problem-solving skills, balancing delivery speed with long-term maintainability and operational reliability.
• Be based in London and able to work full-time on-site with the team during standard business hours.

Nice to have

• Experience contributing to platforms used by global financial institutions such as banks, asset managers, private equity firms, law firms, and advisors.
• Familiarity with regulated industries and the constraints that come with compliance, auditability, and data governance.
• Background working with large, complex datasets and performance-critical data processing pipelines.
• Exposure to AI/ML workflows in production environments, especially where models are used to enhance financial data and analytics.
• Experience building or consuming internal developer platforms, paved-road infrastructure, and self-service tooling.
• Knowledge of financial data models, reference data, and hierarchies used in debt markets.
• Understanding of security and privacy best practices for handling sensitive client and market data in cloud environments.

Practical notes

• Compensation details are not provided in the source material.
• The role is full-time and based in London.
• Visa sponsorship information is not mentioned in the source material.
• No application deadline is stated in the source material.