Staff Software Engineer, Flex
Backend, Money Team
$170-250k
Salary dependent on location
More information about location
Flexible rent payment application
Be an early applicant
Flexible rent payment application
501-1000 employees
Be an early applicant
$170-250k
Salary dependent on location
More information about location
501-1000 employees
Company mission
To help people pay for the things that matter most.
Role
Who you are
- 6–8+ years of professional software engineering experience, with a focus on backend development
- 4+ years of hands-on Java experience (Spring core/web/boot, Gradle, JUnit, JVM tuning & performance)
- Strong computer science fundamentals and proven experience designing scalable, distributed systems
- Deep experience building or operating financial systems, including payments, money movement, ledgers, settlements, reconciliation, billing, or banking infrastructure
- Experience integrating with payment processors, settlement, card networks, banking partners
- Strong understanding of transactional systems, financial data consistency, idempotency, auditability, and fault tolerance in distributed environments
- Skilled at working with both technical and non-technical stakeholders, aligning on scope and delivery
- Ability to write high-quality, testable, maintainable, and secure code
- Hands-on experience with AWS (EKS, Aurora RDS, Elasticache, DynamoDB), containerization (Docker/Kubernetes), and relational + NoSQL databases (MySQL, PostgreSQL, DynamoDB)
- Proficient with CI/CD pipelines (GitHub Actions preferred), git, and build automation
- Familiar with observability and monitoring tools (e.g., DataDog) for maintaining service availability
- Excellent communicator, comfortable collaborating in globally distributed teams
- Track record of mentoring engineers and raising team standards through best practices
What the job involves
- We are seeking a Staff Software Engineer to join our Money Team, responsible for building and scaling the financial infrastructure that powers payments, billing, subscriptions, payouts, ledgers, and other money movement systems across the company
- As a Staff Engineer, you will provide technical leadership across multiple teams, drive the architecture of mission-critical financial platforms, and help ensure our systems are secure, reliable, compliant, and scalable
- You will partner closely with Product, Finance, Risk, Compliance, Data, and Engineering teams to deliver high-impact solutions that directly affect revenue, customer experience, and business operations
- Design, build, and scale backend services and APIs that power Flex's core financial infrastructure, including payments, money movement, billing, settlements, reconciliation, and ledger systems
- Lead the architecture and evolution of highly available, fault-tolerant financial platforms that process and track millions of dollars in transactions with accuracy, reliability, and auditability
- Provide technical leadership and guidance on distributed systems design, financial data consistency, transaction integrity, and long-term platform strategy
- Drive the delivery of highly impactful initiatives end-to-end, from requirements gathering and technical design through implementation, rollout, and operational excellence
- Partner closely with Product, Finance, Risk, Compliance, Operations, and cross-functional engineering teams to deliver scalable and compliant payment experiences
- Build robust systems that integrate with external payment processors, banking partners, card networks, and financial service providers
- Design and implement resilient ledger, settlement, and reconciliation workflows that ensure financial accuracy across the ecosystem
- Drive adoption of engineering best practices across the organization, including observability, automated testing, reliability engineering, CI/CD, and secure software development
- Mentor and support engineers on the team, raising the technical bar and fostering a culture of technical excellence and ownership
- Operate mission-critical financial services in production with stringent uptime, security, compliance, and performance requirements
- Contribute to the evolution of Flex's service-oriented architecture, event-driven systems, APIs, message queues, and scalable financial platforms
- Balance hands-on execution with architectural leadership, ensuring both rapid delivery and long-term maintainability of critical money movement systems
Our take
Many people struggle to pay their rent every month, with a variety of bills hitting their bank accounts simultaneously. Whilst many of these people earn enough money to cover their bills, the inflexible nature of monthly bills can make the all-in-one payment a harder obstacle.
Flex provides a mobile application for the flexible payment of rent, allowing users to pay their landlords through flexible payment plans, reschedule payments when necessary, and protect their funds through Overdraft Protection. The company achieves this by partnering with estate agents and paying their resident's bills upfront, taking on the challenges that landlords would normally have due to late payments.
Flex has experienced extremely rapid growth since its founding which has caused some issues, as it struggled to keep up with the surge in new customers. Having made improvements to its product and scaled its customer service team, it is set to continue providing a service that has come to be highly valued by both tenants and landlords.
Freddie
Company Specialist at Welcome to the Jungle
Insights
10% employee growth in 12 months
Company
Funding (last 2 of 5 rounds)
Feb 2022
$160m
SERIES C
Apr 2021
$46.6m
SERIES B
Total funding: $225.1m
Company benefits
- Medical, Dental & Vision: Your healthcare will be available from Day 1— giving you immediate peace of mind — with best in class coverage and options.
- Parental Leave: Step away with paid time off to focus on family and life’s newest chapter.
- NYC HQ: Collaborate in our lively New York headquarters, with new office space on the way!
- 401(k) Retirement Savings: Plan ahead with our 401(k) program to grow your future. And starting early 2026, employees will be eligible for a company match!
- Flex Giving: Flex Giving empowers employees to support local nonprofits advancing housing stability in the communities we call home.
- Employee Assistance Fund: Confidential financial support to teammates facing unexpected hardships or emergencies.
- Hybrid Work Policy: Work flexibly from home, with in-person collaboration and events that matter.
- Unlimited PTO + Holidays: Take the time you need— whether that’s a vacation, recharge, or simply a long weekend
- Free Flex Subscription: As a Flex employee, you'll have full access to our services without charge.
- GrubHub Credit: Enjoy meal credits while in the office, so you’re fueled for the workday ahead.
Company HQ
Midtown Manhattan, New York, NY
Leadership
Shragie Lichtenstein
(Co-Founder & CEO)Prior to co-founding Flex in 2019, Shragie co-founded Boundless Reality. They graduated from Yeshiva University in 2015 with a Bachelor's Degree in Finance.
YeTong Shao
(Co-Founder)Prior to co-founding Flex in 2019, YeTong co-founded Boundless Reality alongside Shragie. They graduated from the University of Chicago with a Bachelor's Degree in Mathematic & Economics.
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