Building ABF outside the monolith: a service boundary for financial data

9hack: Inside 9fin's second hackathon of 2026

Starting summer on a high, 9finners from across engineering, AI, data science, product and design teams paused their usual work for two days to focus on exchanging ideas and producing practical, valuable solutions to real engineering challenges.

Building scalable authentication and authorisation at 9fin

At 9fin, we’re scaling faster than ever before and are spinning up APIs internally for better decoupling and separation of concerns, while quickly introducing new product surfaces such as MCPs and agents. As our architecture evolved, this highlighted an opportunity to broaden our authentication capabilities beyond the core application supporting our web interface, which handled user-session verification in-app.

Information Retrieval for agents in finance: Why the top open reranker model made our system worse

How 9fin evaluated open rerankers for agentic RAG in debt markets — and why the top public benchmark model reduced retrieval precision.

From Postgres RLS to OpenFGA: Lessons from building (and replacing) our authorisation system

How 9fin migrated from PostgreSQL Row Level Security to OpenFGA for scalable relationship-based access control in sensitive financial systems.

Beyond the model: how we’re making AI in debt markets work at scale

Data excellence at 9fin