Flex Logo

Flex

Senior Software Engineer, Fullstack

Sorry, this job was removed at 08:07 p.m. (MST) on Wednesday, Dec 10, 2025
Easy Apply
In-Office or Remote
3 Locations
Easy Apply
In-Office or Remote
3 Locations

Similar Jobs

2 Days Ago
Remote
USA
150K-220K Annually
Senior level
150K-220K Annually
Senior level
Artificial Intelligence • Machine Learning • Natural Language Processing • Software • Conversational AI
As a Senior Full Stack Software Engineer, responsibilities include building and maintaining backend services, designing APIs, optimizing AI workflows, and collaborating within a team to drive innovation in voice AI applications.
Top Skills: Aws AmplifyDynamoDBGraphQLNext.JsNode.jsReactRestSocket.IoTypescript
17 Days Ago
Easy Apply
Remote
USA
Easy Apply
186K-219K Annually
Senior level
186K-219K Annually
Senior level
Artificial Intelligence • Blockchain • Fintech • Financial Services • Cryptocurrency • NFT • Web3
The role involves designing and integrating backend services and UIs, working with distributed systems and Blockchain technology, while collaborating across teams to enhance user experience and product offerings.
Top Skills: Blockchain TechnologiesDistributed SystemsEthereumEvent-Driven PatternsFull-Stack EngineeringMicroservices Architecture
17 Days Ago
Easy Apply
Remote
USA
Easy Apply
180K-219K Annually
Senior level
180K-219K Annually
Senior level
Artificial Intelligence • Blockchain • Fintech • Financial Services • Cryptocurrency • NFT • Web3
Design and maintain SDKs for embedded wallets, develop user authentication methods, produce documentation, and troubleshoot fullstack issues while collaborating with various teams and customers.
Top Skills: AndroidFlutteriOSOpenapiReactReact NativeTypescriptUnity

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 2025 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 Job

Flex is looking for a Software Engineer (Fullstack) who will be responsible for implementing the various backend and frontend systems that support all business features.

In this role, you will be part of the product engineering 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 and 3+ with React/Typescript is required for this position.

QualificationsMinimum Qualifications
  • 6+ years of professional software development experience.
  • 4+ years of hands-on experience with Java.
  • 3+ years of experience with React or React Native.
  • 3+ years of experience with TypeScript.
  • Having experience building high-quality mobile and web UIs to specifications is a must to have.
  • 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
  • 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 architectures and tools in React Native and React ecosystems (Hooks, Components, Context, Redux).
  • 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.
The salary compensation range for this role will be commensurate with the candidate's experience and Flex's internal leveling guidelines and benchmarks.
  • For working locations in NY/NJ/CA, the base salary pay range will be $197,000-$213,000
  • For all other states, the base salary pay range will be $177,000-$192,000

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.

We offer many employee benefits & perks. For full-time U.S based positions we offer:

  • Competitive medical, dental, and vision available from Day 1
  • Company equity
  • 401(k) plan with company match (our company match kicks off at the beginning of 2026)
  • Unlimited paid time off + 13 company paid holidays
  • Parental leave 
  • Flex Cares Program
  • Free Flex subscription

 For full time non-US employees, we offer

  • Competitive compensation + company equity
  • Unlimited PTO

What you need to know about the Colorado Tech Scene

With a business-friendly climate and research universities like CU Boulder and Colorado State, Colorado has made a name for itself as a startup ecosystem. The state boasts a skilled workforce and high quality of life thanks to its affordable housing, vibrant cultural scene and unparalleled opportunities for outdoor recreation. Colorado is also home to the National Renewable Energy Laboratory, helping cement its status as a hub for renewable energy innovation.

Key Facts About Colorado Tech

  • Number of Tech Workers: 260,000; 8.5% of overall workforce (2024 CompTIA survey)
  • Major Tech Employers: Lockheed Martin, Century Link, Comcast, BAE Systems, Level 3
  • Key Industries: Software, artificial intelligence, aerospace, e-commerce, fintech, healthtech
  • Funding Landscape: $4.9 billion in VC funding in 2024 (Pitchbook)
  • Notable Investors: Access Venture Partners, Ridgeline Ventures, Techstars, Blackhorn Ventures
  • Research Centers and Universities: Colorado School of Mines, University of Colorado Boulder, University of Denver, Colorado State University, Mesa Laboratory, Space Science Institute, National Center for Atmospheric Research, National Renewable Energy Laboratory, Gottlieb Institute

Sign up now Access later

Create Free Account

Please log in or sign up to report this job.

Create Free Account