Senior Engineering Manager

Flex is a growth‑stage, NYC headquartered Fin Tech 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. Will you be a part of the team?

We are hiring a Senior Engineering Manager to lead the Payments platform team, responsible for the systems that charge customers, collect funds, and handle refunds. This team owns the end‑to‑end payment lifecycle: authorization, charge, refund, reconciliation, and financial integrity across multiple payment rails and processors. You will lead a team of backend engineers responsible for building a highly reliable, compliant, and cost‑efficient payments platform that supports rapid product expansion while safeguarding customer funds.

This role requires hands‑on leadership; you will drive architecture, execution, operational excellence, and team growth while partnering closely with Product, Risk, Finance, Compliance, and external financial partners.

• Consumer Engineering:
  Builds the APIs and backend systems powering Flex’s consumer‑facing mobile and web apps. This team focuses on delivering scalable services for a seamless rent payment experience.
• Partner Integrations Engineering:
  Owns the backend services and integrations that connect Flex to financial partners and payment networks, ensuring secure, reliable payment flows and partner‑facing experiences.
• Core Platform Engineering:
  Maintains the backend services and infrastructure supporting all business features, including Payments, Ledger, Identity, and Settlement, providing the foundation for all of Flex’s products.

• Define and execute the long‑term architecture of Flex’s multi‑rail payments platform (Card, ACH, RTP, OCT, Fed Now, etc).
• Ensure financial correctness across ledgering, settlement, reconciliation, and refunds.
• Drive reliability and resilience for mission‑critical money movement systems.
• Guide design reviews and make high‑impact technical decisions.

• Lead cross‑team initiatives spanning product, risk, and finance workflows.
• Own delivery of large, ambiguous projects from concept to production.
• Improve system scalability, observability, and incident response practices.
• Reduce payment processing costs through routing strategy and platform optimization.

• Manage, mentor, and grow a team of backend engineers.
• Establish strong ownership culture and operational excellence.
• Hire and develop senior engineers and future technical leaders.
• Elevate engineering quality, testing discipline, and design rigor.

• Ensure high availability and financial accuracy SLAs.
• Lead incident response for payment‑related issues.
• Build guardrails to prevent financial and compliance risk.
• Partner with Risk & Compliance teams on regulated workflows.

• 8+ years of backend engineering experience and 3+ years managing engineers.
• Experience building or operating payments, fintech, banking systems.
• Strong understanding of distributed systems reliability and data integrity.
• Experience owning production services with strict uptime and correctness requirements.
• Track record delivering large cross‑functional initiatives.

• Experience with payment rails (ACH, card networks, RTP, wires, payouts).
• Experience integrating payment processors (Stripe, Checkout, Adyen, bank APIs, etc).
• Experience in regulated environments (KYC, NACHA, chargebacks, reconciliation).
• Familiarity with financial ledger or accounting correctness principles.
• Background scaling high‑growth consumer or fintech platforms.

Flex takes a market‑based approach to pay, and compensation…