Senior Data Scientist

In short:

A high-growth fintech is looking to bring on a Senior Data Scientist to build and ship production-grade scam intelligence that runs before payments clear. You’ll turn multi-source signals (transaction context, counterparty intelligence, behavioural patterns, unstructured evidence) into reliable, explainable risk decisions - under real-world constraints like latency, uptime, and auditability.

About the company:

The company is building a payment intelligence layer for banks - running real-time “investigations” on payments to provide rich context on the counterparty and situation. The goal: intercept scams while ensuring genuine payments flow smoothly. They’re early-stage, moving fast, and working on problems where correctness, security and reliability are non-negotiable.

Who we’re looking for

You’re a hands-on ML/AI builder who’s comfortable owning the full loop: data → modelling → deployment → monitoring → iteration. You care about practical decisioning (not just metrics), you’re thoughtful about trade-offs (customer experience vs protection), and you’re excited about building systems that are explainable and bank-grade.

What you’ll do

- Build and ship scam risk models and signals (typology classification, risk scoring, decision logic)

- Engineer features across heterogeneous data: transaction context, behavioural sequences, counterparty signals, network/graph patterns, and unstructured evidence

- Design calibrated outputs (scores + reason codes) that are actionable and explainable for banking workflows

- Own evaluation end-to-end: leakage avoidance, cost-sensitive metrics, thresholding, phased rollouts, and post-incident learning

- Productionise ML: packaging, deployment, monitoring, drift detection, and retraining strategies

- Collaborate closely with backend/product teams to integrate intelligence into real-time payment flows

- Work alongside agent/LLM workflows for evidence gathering and synthesis, while keeping the decision core predictable and auditable

Must-haves:

- Strong experience shipping applied ML into production (not just experimentation)

- Strong Python + ability to write maintainable, tested code

- Strong SQL + comfort working directly with messy, high-volume data

- Solid modelling judgement: calibration, leakage, bias, thresholding, cost trade-offs, monitoring/drift

- Experience building decisioning systems where reliability, latency, and explainability matter

Nice-to-haves:

- Experience in fraud/scams, payments, risk, trust & safety, AML, or adjacent domains

- Familiarity with graph/network features and entity resolution style problems

- Experience with MLOps tooling (model registry/MLflow, feature stores, orchestration)

- Comfort with cloud-native/event-driven systems and working closely with platform/backend engineers

- Experience integrating unstructured signals (text/embeddings/RAG style pipelines) into decision systems

Why join

- Work on a mission with real-world impact: stopping scams before money leaves

- Build real-time, bank-grade ML systems with ownership end-to-end

- Early team + high autonomy + meaningful technical decisions

- London hybrid working + visa sponsorship available