About this opportunity
Flex lists this Senior Software Engineer, Backend opportunity in san francisco, California. Review the employer’s description below for duties, qualifications and application requirements.
Job description
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. Will you be a part of the team?
About Our Opportunities
Flex exists to make paying rent work the way real life actually works — smoothing out cash flow, helping renters avoid late fees, and letting them build credit instead of falling behind. As a Senior Backend Engineer, you'll design, build, and scale the services and integrations behind Payment, Billing, Identity, and partner integrations that keep rent moving on time for renters every month — leading scoping, design, and implementation for the APIs you own, driving your own production rollouts to completion with minimal oversight, and working closely with product, design, and engineering peers to solve renters' most pressing problems in small, frequent iterations rather than big, risky releases.
About Our Team(s)
We have some really exciting teams who are looking for an amazing engineer like you! Check them out!
Partner Integrations - Partner integrations work to standardize APIs, tools, and processes that let external partners connect to Flex for data sharing and payments across entry points like Flex Anywhere and Quick-Pay
Fin Platform - Fin Platform is the monitoring and operations layer for Flex's billing and payment systems, covering dashboards, SLIs/SLOs, runbooks, deployment and on-call procedures to ensure reliability and readiness.
Money Team - builds and owns the platforms, tooling, and documentation powering Flex's payments, wallet, and settlement finance systems.
Who Thrives Here?
A Doer — you get things done efficiently, and you're comfortable rolling up your sleeves when something's blocking the team.
An Owner — you take full accountability for what you build, from design through production, and you always have a plan B.
Someone Collaborative — you bring people together to pressure-test ideas rather than working in a silo.
Someone with Precision — your code and your communication are both clear, because ideas only matter once others can act on them.
Someone Resilient — systems break and priorities shift, and you adapt without losing momentum.
Someone Humble — you care more about getting to the right answer than being the one who's right.
Qualifications
Minimum Qualifications
Minimum of 6 years experience in software engineering
Minimum of 4 years experience with Java
Ability to work on a globally-distributed team with a high degree of ownership
Experience working with technical and non-technical stakeholders, successfully aligning and setting expectations on scope and delivery
Ability to grow in a fast-paced and dynamic environment that will challenge you to always bring your best
Experience building robust, fault-tolerant systems with multiple external dependencies
Experience designing, building, and maintaining data pipelines
Proficient in Java frameworks and tools used at Flex, including Spring (core/web/boot), Gradle, JUnit, and JVM (memory/performance tuning, GC)
Experience with Service-Oriented Architecture, REST APIs, Message Queues, and scalable architectures
Experience with AWS (EKS, Aurora RDS, Elasticache, DynamoDB) and containerization tools
Preferred Qualifications
Proficient in CI/CD systems (preferably GitHub Actions), git, and automation
Skilled in observability and monitoring tools, such as DataDog, to ensure high availability
Experienced with big data platforms and tooling, including Snowflake
Proficient in Infrastructure as Code, using tools like CDK and Terraform
Skilled at elevating team standards through best practices, and mentoring junior engineers
Excellent written and verbal communicator, with experience in cross-functional collaboration
Compensation
Flex takes a market-based approach to pay, and compensation may vary depending on your primary work location. Work locations are categorized into one of three tiers based on a cost of labor index for that geographic area. The successful candidate’s starting pay will be commensurate with their experience, qualifications, and Flex’s internal leveling guidelines and benchmarks.
Tier 1 (NYC/Bay Area, Los Angeles, Seattle) $172,000 — $215,000 USD
Tier 2 (Austin, Washington D.C. Philadelphia, San Diego, Chicago, Atlanta) $154,800 — $193,500 USD
Tier 3 (Salt Lake City, all other USA cities) $146,200 — $182,750 USD
Life at Flex
We understand that it takes a diverse team of highly intelligent, curious, determined, empathetic, and self aware people to grow a successful company. Our HQ is located in New York City, but we have employees located throughout the US, Australia, Canada and South America. We are growing quickly, but deliberately, with a focus on building an inclusive culture. Our dynamic team has incredible perspectives to share, just as we know you do, and we take great pride in being an equal opportunity workplace.
Offices
Roles posted in New York, San Francisco, and Salt Lake City are hybrid positions with on-site expectations of 2-3 days per week in our local offices. For candidates outside of these areas, you may be eligible for our relocation assistance program.
Benefits
For full-time U.S. employees we offer:
Competitive medical, dental, and vision
Company equity
401(k) plan with company match
Unlimited paid time off + 13 company paid holidays
Parental leave
Free Flex subscription
For full-time non-U.S. employees, we offer:
Competitive compensation + company equity
Unlimited PTO
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Worksite address
san francisco, CA, 94199, US
Who can apply
Review the original listing for work authorization, qualifications and employer requirements.