{"id":15449,"url":"https://alion.io/job/9fin-senior-product-engineer-fullstack","title":"Senior Product Engineer","company":{"id":4757,"name":"9fin","domain":"9fin.com","url":"https://alion.io/company/9fin","size_band":"201-500","is_staffing_agency":false,"employer_type":"direct","is_intermediary":false,"listed_via":null,"ats_vendor":"Ashby","truth_index":{"grade":"B","score":79,"open_postings":7,"ghost_share":0,"stale_share":0.857,"repost_share":0,"time_to_fill_p50_days":44,"computed_at":"2026-10-17T05:46:00Z"}},"role":"Backend","role_family":"Backend","seniority":"senior","employment_type":"full_time","work_mode":"on_site","remote_scope":null,"remote_scope_basis":null,"remote_working_hours":null,"hiring_geo_confidence":"structured","locations":["London, United Kingdom"],"countries":["GB"],"hiring_countries":[],"hiring_countries_total":0,"salary":null,"salary_estimate":{"min_usd":107000,"max_usd":204000,"period":"year","method":"role_seniority_country_remote_cell","sample_n":125},"experience_years_min":null,"visa_sponsorship":false,"relocation_package":false,"has_equity":true,"technologies":[{"name":"Amazon ECS","optional":false},{"name":"AWS","optional":false},{"name":"ChatGPT","optional":false},{"name":"Claude","optional":false},{"name":"Copilot","optional":false},{"name":"Cursor","optional":false},{"name":"Docker","optional":false},{"name":"JavaScript","optional":false},{"name":"React.js","optional":false},{"name":"TypeScript","optional":false},{"name":"FastAPI","optional":true},{"name":"Flask","optional":true},{"name":"PostgreSQL","optional":true},{"name":"Python","optional":true}],"status":"live","first_seen_at":"2026-07-21T10:53:26Z","employer_posted_date":"2026-07-21","last_verified_at":"2026-10-17T06:22:47Z","board_verified":true,"closed_at":null,"days_open":87,"trust":{"level":"ok","repost_count":null,"flags":[],"days_open":87},"description":"About 9fin\n9fin is the AI platform powering global debt markets - the world’s largest asset class at over $145 trillion.\nDebt 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.\nToday, 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.\nWe’re at a defining inflection point. With proven product-market fit and strong, global market pull, 9fin is accelerating toward becoming the category-defining platform for debt markets worldwide.\nWhat you'll work on\nAs part of a cross functional team, lead projects by defining and designing systems, building proof of concepts, and delivering new service functionality - including APIs, data processing and automation - while collaborating with Product and Clients\n\nDevelopment and engineering primarily on the backend services and web application hosted tools and systems of the 9fin platform.\n\nPlay an impactful role within project teams as a senior IC, running code reviews, mentoring other developers, leadership & involvement in early research and experimentation with new technologies providing input for new features and products.\n\nContinually improve the 9fin codebase taking the chance to automate, refactor and document when it’s most impactful..\n\nVery diverse web platforms, from complex financial data modelling, complex access control business logic, capturing environmental, emission, energy data, incorporation of ML/AI prediction services, data visualisation serving and automation systems.\n\nCollaboration and teamwork: Cross functional teams are formed for all projects including the appropriate domain expertise from 9fin financial, legal and editorial colleagues. This allows the best quality information and feedback to go directly to engineering project teams. Your ability to explain and break down complex projects to non technical audiences will enable productive and efficient team progress.\n\nDeveloper Experience: Through managed automated preview environments, feature flags and well maintained non production environments. You will be able to move with velocity and get feedback and iterate quickly.\n\nOur Stack\nPython is the dominant backend language used\n\nFlask & FastAPI\n\nReact & TypeScript\n\nTyping is used within our Python stack to power automated documentation and API definitions\n\nRelational Databases (PostgreSQL) at the heart of majority of services\n\nWe have our own internal developer platform with standardised paved road approaches to infrastructure to bring your code into production as quickly as possible.\n\nWe’re AWS for Cloud hosted services\n\nHeavy use of AWS lambda Serverless\n\nDocker (AWS ECS) for uniform development/deployment from dev to prod\n\nRequirements\nThis role will be a great fit if you:\nHave 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.\n\nComfortable moving between frontend and backend work, picking the right tool for the problem rather than specializing in one area.\n\nStrong knowledge of modern JavaScript/TypeScript and frameworks such as React, alongside experience building scalable backend services and APIs.\n\nComfortable leveraging modern AI-assisted development tools (e.g. Cursor, Claude, ChatGPT, GitHub Copilot) to improve productivity while maintaining high engineering quality.\n\nA strong product mindset with an eye for user experience, working closely with designers and product managers to craft intuitive, polished interfaces.\n\nAble to independently own features from idea through design, implementation, deployment and iteration.\n\nStrong system design and problem-solving skills, balancing speed with long-term maintainability.\n\nBenefits\nWe’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.\nFinancial & Insurance\nCompetitive Salary (our salary bands are benchmarked at the top end of the market)\n\nEquity options\n\nPension (your minimum contributions are 4% with 9fin matching up to 7%)\n\nPrivate Medical Insurance\n\nPaid sick leave with Income Protection for long periods of illness\n\nGroup Life Assurance\n\nSeason Ticket Loan & Cycle to Work schemes\n\nTime off\n25 holiday days per year\n\nLocal public holidays (with the ability to exchange them for alternative days)\n\nHybrid working model\n\nWork abroad for up to 3 months a year\n\n1 month paid sabbatical after 5 years of service\n\nEnhanced parental leave & flexible working arrangements available\n\nTraining & Culture\nProfessional learning and development budget\n\nQuarterly team socials\n\nSummer and Winter company social events\n\n9fin is a hybrid company, and the office is a regular part of how we work. From January 2027, all employees will work from their designated 9fin office on Tuesdays and Wednesdays. Some teams may be asked to be in the office more often, where the nature of their work calls for it. For the rest of the week, you may work from wherever works best for you and your team.\n9fin is an equal opportunities employer\nAt 9fin we are dedicated to building and promoting a fair and inclusive workplace where everyone can reach their full potential and truly belong. We recognize 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. 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