Senior Software Engineer, Backend FinPlatform

Flex group; New York (NY); On-site; USD 146,200 - 215,000; Full time

Benefits offered by this job

Company equity

401(k) with company match

Unlimited paid time off

Parental leave

Free Flex subscription

Job summary

Flex, a NYC-based FinTech company, seeks a Senior Software Engineer (Backend) to own backend systems powering payment, billing and identity services. You will design, implement, test, and scale APIs with a focus on distributed, fault-tolerant systems and data pipelines.

The role requires leadership in API scoping and production rollouts in an agile environment. Ideal candidates have 6+ years in software engineering, 4+ years with Java, and strong experience with Spring, REST, AWS, CI/CD and

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 ownership.
• Experience with SOA, REST APIs, message queues, scalable architectures.

Responsibilities

• Implement backend systems and services powering FinTech features.
• Design, develop, test, and scale APIs and integrations.
• Lead scoping and design for APIs and drive production rollouts.

Skills

Java

Spring

REST APIs

AWS

CI/CD

Data pipelines

Distributed systems

Observability

Team leadership

Tools

GitHub Actions

Kubernetes

Gradle

JUnit

Docker

Job description

Senior Software Engineer, Backend FinPlatform

Remote

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 the role

Flex is looking for a Senior Software Engineer who will be responsible for implementing the various backend systems that support all business features.

In this role, you will be part of the backend engineer team, responsible for the services and integrations that power our products, such as Payment, Billing, Identity, partner integration, etc. You’ll be designing, developing, testing, and scaling systems needed to deliver great user and partner experiences.

You’ll work closely with your product, design and engineering peers to solve our users' most pressing problems around rent payment. You’ll roll out changes to our customers in an agile manner with a delivery cadence that favors small, frequent iterations. The ideal candidate will be comfortable leading scoping, design and implementation for APIs they build and can drive their production rollouts to completion with minimum oversight.

A minimum of 4 years of experience with Java is required for this position.

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.

$172,000 - $215,000 USD

$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.

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