Full Stack Engineer

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.

We’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.

• As part of a cross-functional team, contribute to projects by helping design systems, building proof of concepts, and delivering new service functionality — including APIs, data processing, and automation — while collaborating closely with Product and Clients.

• Development and engineering primarily on backend services and web-application–hosted tools and systems within the 9fin platform.

• Play an impactful role within project teams as an individual contributor, participating in code reviews, collaborating with peers, and contributing ideas during research and experimentation with new technologies.

• Continually improve the 9fin codebase by taking opportunities to automate, refactor, and document where it’s most valuable.

• Work across a diverse set of web platforms, including financial data modelling, access-control business logic, environmental and emissions data capture, integration with ML/AI prediction services, data visualisation, and automation systems.

• Collaboration and teamwork:
  All projects are delivered by cross-functional teams that include domain expertise from 9fin’s financial, legal, and editorial colleagues. You’ll work closely with non-technical stakeholders and help explain technical concepts in a clear, accessible way to support effective team progress.

• Developer experience:
  You’ll work within a strong developer experience setup, including automated preview environments, feature flags, and well-maintained non-production environments, enabling rapid iteration and feedback.

Our Backend Stack

• Python is the dominant backend language used

• Flask & FastAPI

• Typing is used within our Python stack to power automated documentation and API definitions

• Relational Databases (Postgre
  
  SQL) at the heart of majority of services

• We have our own internal developer platform with standardised paved road approaches to infrastructure to bring your code into production as quickly as possible.

• We’re AWS for Cloud hosted services

• Heavy use of AWS lambda Serverless

• Docker (AWS ECS) for uniform development/deployment from dev to prod

This role will be a great fit if you:

• Have experience working as a Full-Stack or Backend-leaning Engineer within a product team, contributing to system design discussions and delivering production software.

• Can plan and reason about software effectively, clearly communicating how your work fits into larger systems and delivers value to clients.

• Have hands-on experience designing and implementing data flow through software, from persistent storage to API endpoints, applying industry best practices for validation and reliability.

• Have experience with Python and web frameworks (we currently use FastAPI with strong typing and Pydantic).

• Have experience building and consuming APIs, ideally within a service-oriented architecture.

• Have a working knowledge of SQL for querying and working with relational data.

• Are a collaborative and proactive communicator, comfortable working with engineers and non-engineers across the business.

• Care about code quality, writing testable and maintainable code, and actively participating in code reviews — both receiving feedback and reviewing others’ work.

We’re a scaling start up and we enjoy sharing our success, when the company succeeds, we always reinvest that in…