Senior Platform Engineer - Developer Experience in London

About 9fin: 9fin is the AI platform powering global debt markets — the world’s largest asset class at over $145 trillion. Debt markets are vast, global, and mission-critical, yet still run on fragmented data, PDFs, and manual workflows. 9fin replaces this broken infrastructure with a single platform that centralises proprietary credit data, deep analysis, and high-value workflows across global markets. Today, 9fin powers teams at 300+ blue-chip institutions worldwide, including global banks, asset managers, private equity firms, law firms, and advisors. The business is scaling at exceptional speed, with rapid expansion in the US and best-in-class retention driven by deep workflow adoption.

The opportunity: We are looking for a Senior Developer Experience Engineer to help make software development at 9fin faster, simpler and safer. This is a software engineering role focused on the tools, systems and paved roads that other engineers use. You will work across the software development lifecycle, from creating a new service through to testing, deployment, observability and operating it in production. You will join an established Platform team and work alongside our existing Developer Experience Engineer. You will speak directly with engineers, understand where they are losing time or carrying unnecessary complexity, and build solutions that teams want to adopt. Your customers are 9fin's software engineers. You will have the autonomy to solve problems that help them build products quickly, securely and to a high standard of quality. The goal is not to centralise every engineering decision within Platform. It is to give teams sensible defaults, effective self-service tools and a clear path to production.

What you'll work on: Every day is different, but here are examples of the kind of things you’ll work on:

• Building and maintaining internal tools, services, APIs and command-line applications.
• Improving workflows across coding, testing, code review, deployment and production operations.
• Creating service templates and paved roads that make it easier to build secure, observable and reliable software.
• Improving the speed, reliability and usability of our CI/CD systems.
• Developing reusable platform capabilities that product engineers can consume through self-service.
• Helping engineers use observability effectively, with good defaults for logs, metrics, traces and service-level indicators.
• Working directly with engineers to understand friction, test ideas and support adoption.
• Using feedback and workflow data to measure whether changes have improved the developer experience.
• Contributing production-quality code, tests, documentation and operational support.

About you: This role will be a great fit if:

• You are a strong software engineer with experience designing, building, testing and operating production software.
• You are proficient in at least one modern programming language. We care more about engineering fundamentals than a particular language.
• You understand the software development lifecycle and have practical experience improving how software is built, tested, deployed or operated.
• You have strong opinions about what makes software development effective, while remaining pragmatic about different teams and contexts.
• You can design maintainable systems and make sensible trade-offs between speed, quality and complexity.
• You have experience with CI/CD, containers and cloud infrastructure.
• You enjoy building tools and platforms for other engineers.
• You take a product approach to internal tooling: understanding user needs, validating solutions and measuring adoption.
• You can independently own a problem from discovery through to delivery and adoption.
• You communicate clearly through code, documentation and technical discussions.
• You have a real appetite for learning and self-improvement.

Nice to haves: You do not need to have experience in all of these areas, but any of the following would be useful:

• AWS and infrastructure as code. We currently use AWS and Terraform.
• Building internal developer platforms, developer portals, CLIs or service templates.
• Observability using tools such as OpenTelemetry, CloudWatch or SigNoz.
• Reliability engineering, incident response or production operations.
• Experience in fintech or another regulated environment.

Benefits: We’re a scaling start up, and we enjoy sharing our success. When the company succeeds, we always reinvest that in our people. We also offer huge amounts of responsibility, an abundance of opportunity for growth and a platform to truly excel.

• Competitive Salary (our salary bands are benchmarked at the top end of the market)
• Pension (your minimum contributions are 4% with 9fin matching up to 7%)
• Private Medical Insurance
• Paid sick leave with Income Protection for long periods of illness
• Group Life Assurance
• Season Ticket Loan & Cycle to Work schemes

Time off:

• 25 holiday days per year
• Local public holidays (with the ability to exchange them for alternative days)
• Hybrid working model, to allow you the flexibility to decide how, where and when you do your best work
• Work abroad for up to 3 months a year
• 1 month paid sabbatical after 5 years of service
• Enhanced parental leave & flexible working arrangements available

Training & Culture: Professional learning and development budget, quarterly team socials, summer and winter company social events.

9fin is an equal opportunities employer. At 9fin we are dedicated to building and promoting a fair and inclusive workplace where everyone can reach their full potential and truly belong. We recognise that building diverse teams enables a more creative and productive environment. If you’re excited about this role but your experience doesn’t perfectly align with the job description, we encourage you to apply anyway. You might just be who we’re looking for — either for this role, or perhaps another.