Senior Staff, Decision Scientist, Risk

Flex•New York, NY

2d•Hybrid

About The Position

Flex is a growth-stage, NYC headquartered FinTech company that is creating the best rent payment experience. It’s hard to believe that it’s 2026 and paying rent on time is expensive, inflexible, and difficult. We’re here to change that! Flex enables our users to pay rent throughout the month on a schedule that better fits their finances and budget. Our mission is to empower as many renters as possible with flexibility over their most significant recurring expense. After deliberately keeping a stealth profile as we built up unprecedented investor support and an enthusiastic user base, we are looking for motivated individuals to help us keep our mission growing. As a Senior Staff Decision Scientist on the Risk & Decision Science team, you’ll own the strategy and optimization of Flex’s payment decisioning stack. This includes authorization optimization, PSP routing, retries/failover logic, and cost vs. risk tradeoffs across millions of dollars of payment volume. This is a high-impact, senior individual contributor role where you’ll work at the intersection of payments, product, engineering, finance, and data to improve core platform economics and customer experience. If you’ve worked on payments platforms, risk systems, credit, or large-scale decisioning at companies like Stripe, PayPal, Square, Adyen, Affirm, or big tech, this role is very much in that vein.

Requirements

10+ years of experience in payments, risk, credit, decision science, or platform analytics
Strong hands-on skills in Python and SQL and working with large, messy datasets
Experience working on high-scale transactional systems (payments, lending, marketplaces, fintech, or similar)
Familiarity with concepts like authorization optimization, loss modeling, cohort/vintage analysis, or unit economics
Strong product and business intuition—you care about shipping impact, not just analysis
Comfortable operating cross-functionally and owning ambiguous, high-leverage problem spaces

Nice To Haves

Background in fintech, payments, or large tech platforms is a strong plus

Responsibilities

Own and evolve Flex’s payment decisioning and routing strategy across multiple PSPs
Use data to increase authorization rates while reducing processing costs and losses
Design and evaluate retry, failover, and fallback strategies to improve reliability and performance
Analyze large-scale payment and risk data to identify product and platform improvements
Build models and forecasts to understand the impact of policy and product changes
Run experiments and measure tradeoffs between growth, risk, cost, and user experience
Partner closely with Product, Engineering, Finance, and Operations to ship improvements to the payments platform
Define metrics and dashboards to monitor performance and guide strategy
Communicate clear, actionable recommendations to leadership and stakeholders