Senior Software Engineer, Backend

The role

You will work across the stack with a focus on back-end engineering at Flex. You will own large domains such as card processing and issuing, and core ledgering of financial transactions, from design through release.

What you will do

• Own large domains and features related to card processing and issuing, and core ledgering of financial transactions
• Play a critical role in the development, design, and maintenance of Flex's platform and services
• Architect well thought-out services and data models
• Own problems end-to-end, including API contracts, data, scalability, security, observability, and metrics
• Lead by example and mentor engineers in planning, development, and testing
• Drive best-in-class technology frameworks and tooling
• Be on call to solve problems and find solutions for the servicing team

Required qualifications

• Proficiency in NodeJS and TypeScript and server design principles
• Understanding and interest in architectural patterns for highly available, scalable, low-latency, asynchronous systems
• Ability to hold yourself and the team to high standards
• Strong written and verbal communication and interpersonal skills
• Ability to evaluate multiple technical directions and determine tradeoffs
• Strong propensity to make data-driven decisions on technical architecture and project prioritization
• Exposure to modular monoliths and micro-services and their benefits and challenges
• Experience with a cloud provider such as Google Cloud, AWS, or Azure
• Four or more years of relevant industry experience with a track record of shipping high-quality products and features at scale
• A strong work ethic
• Have built and shipped a working project or product, ideally something complex

Benefits

• Meaningful equity
• Founder-level exposure with direct access to leadership, customers, and investors
• Work on real money and real risk at serious scale
• True ownership with small teams, high trust, and real accountability

Before you apply

• Even if you do not fully match the job specifics, the company encourages you to apply

About the company

Flex is building AI-native financial services for business owners, covering banking, credit, payments, personal finance, and financial operations. It has raised $100M+ in equity and $300M+ in debt.