Senior Backend Software Engineer, Flex
$177-213k
Salary dependent on location. + Equity
More information about location
Flexible rent payment application
Be an early applicant
Flexible rent payment application
501-1000 employees
Be an early applicant
$177-213k
Salary dependent on location. + Equity
More information about location
501-1000 employees
Company mission
Flex's mission is to empower as many renters as possible with flexibility over their most significant recurring expense.
Role
Who you are
- Strong computer science fundamentals with a proven track record of building scalable backend systems
- 5–6+ years of professional software engineering experience with a focus on backend development
- 4+ years of hands-on Java experience, with deep knowledge of the Java ecosystem
- Proficient in Java frameworks and tools used at Flex: Spring (core/web/boot), Gradle, JUnit, JVM tuning and performance optimization
- Experience operating services in distributed, service-oriented architectures at scale
- Familiarity with REST API design, mobile API best practices, and message-driven architectures
- Skilled at building robust, fault-tolerant systems and integrating with multiple external dependencies
- Experience designing and maintaining data pipelines and working with big data platforms (bonus: Snowflake)
- Hands-on experience with AWS (EKS, Aurora RDS, Elasticache, DynamoDB), containerization (Docker/Kubernetes), and Infrastructure as Code (CDK/Terraform)
- Skilled in observability and monitoring tools (e.g., DataDog) to ensure high availability
- Ability to write high-quality code that is testable, maintainable, scalable, and secure, using industry best practices throughout the SDLC (unit testing, build automation, CI/CD)
- Excellent communicator, comfortable working with distributed teams and cross-functional stakeholders
- Proven ability to mentor junior engineers and raise the technical bar through best practices
- Risk Platform candidates: Experience in risk engineering, rules engine architecture, and implementing risk/fraud/credit policies in production systems is highly valued
What the job involves
- Flex is hiring Senior Software Engineer, Backend roles across four engineering teams: Consumer, Partner Integrations, Core Platform, and Risk
- When you apply, you will automatically be considered for all open Senior Backend positions, and your placement will be determined based on your experience and expertise assessed during the interview process
- As a Senior Backend Engineer at Flex, you will play a key role in designing, building, and scaling backend services and APIs that power our products, partner integrations, and critical risk management platforms
- You’ll collaborate closely with cross-functional teams to deliver robust, fault-tolerant systems that impact renters and partners at scale
- You will own the end-to-end lifecycle of your services- from requirements and architecture through implementation, testing, deployment, and monitoring- and help elevate the team by driving technical best practices and mentoring junior engineers
- Design, develop, test, and scale backend services and APIs that power Flex’s consumer products, partner integrations, risk management systems, and core platform services
- Build and operate robust, fault-tolerant distributed systems with multiple external dependencies
- Implement service APIs for web and mobile apps, simplifying complex rent payment processing
- Work closely with Product, Design, Infrastructure, Sales, Partner, and Customer Success to deliver features and integrations that delight customers and partners
- Translate feature requirements into technical specifications and lead the architecture and implementation of scalable solutions
- Drive the full lifecycle of services and APIs you build, including deployment, monitoring, and optimization for high availability and performance
- Contribute to evolving Flex’s service-oriented architecture, REST APIs, message queues, and scalable systems design
- Develop risk management systems such as rules engines, ML-powered fraud detection, and high-scale event ingestion pipelines
- Mentor junior engineers and help elevate the team’s engineering practices through code reviews, architecture discussions, and technical leadership
- Ensure services are observable and reliable using monitoring tools and industry best practices
- Collaborate on CI/CD improvements and automation to increase code quality and delivery velocity
- Our Engineering Teams:
- Consumer Engineering: Builds the APIs and backend systems powering Flex’s main consumer-facing products. This team focuses on delivering scalable services for a seamless rent payment experience through our mobile and web apps
- Partner Integrations Engineering: Owns the backend services and integrations that connect Flex to financial partners and payment networks, ensuring reliable, secure payment flows and partner-facing experiences
- Core Platform Engineering: Maintains the backend systems and infrastructure supporting all business features, including Payments, Billing, Identity, and Partner Integrations, ensuring Flex’s foundation is robust and scalable
- Risk Platform Engineering: Develops the platforms and APIs that mitigate credit and fraud risk, enhancing customer accessibility while safeguarding against misuse through advanced rules engines, machine learning, and event data 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
- 100% company-paid medical, dental, and vision
- 401(k) + company stock options
- Unlimited paid time off + company paid holidays
- Parental leave + IVF and adoption support
- Flex Cares Program: Non-profit company match + pet adoption coverage
- Pet Insurance
- Free Flex subscription
Company HQ
Midtown Manhattan, New York, NY
Leadership
Shragie Lichtenstein
(Co-Founder & CEO)Experience working in venture capital investments for Point72 and TVC. Also co-founded Boundless Reality.
YeTong Shao
(Co-Founder)Experience as Data Science Researcher. Also co-founded Boundless Reality.
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