Software Engineer

flex.one; Mission (KS); On-site; USD 110,000 - 145,000; Full time

Job summary

A financial services company is seeking a Software Engineer II to develop product features for managing financial operations. The role involves building user-facing functionalities and APIs while ensuring high-quality code and team collaboration. Ideal candidates will demonstrate strong software fundamentals and a product-oriented mindset. This position offers a competitive salary ranging from $110,000 to $145,000 annually, with opportunities for remote work and professional growth.

Qualifications

• Strong fundamentals in software development.
• Ability to think about user impact and business value.
• Experience with financial services or handling sensitive data is a plus.

Responsibilities

• Own the full lifecycle of medium-sized features and tasks.
• Build user-facing features and backend services.
• Participate in code reviews and provide feedback.

Skills

Software development fundamentals

Product sense

Problem-solving

Team collaboration

English proficiency

Work ethic

Tools

Typescript

PostgreSQL

GCP

Job description

Flex is building the AI-native private bank for business owners.

We’re re-architecting the entire financial system for entrepreneurs—from the first dollar a business earns to how that value compounds, moves, and is ultimately spent in real life. Banking, credit, payments, personal finance, and financial operations—rebuilt from the ground up as a single, intelligent system.

Since launching publicly in September 2023, Flex has scaled from zero to nine-figure annualized revenue, with a clear path to profitability by late 2025. We move fast, ship relentlessly, and operate with extreme ownership.

Our customers are affluent business owners ($3–$200M in revenue)—the backbone of the economy and one of the most underserved segments in finance. They’re stuck with outdated banks and fragmented tools. We’re replacing all of it. The opportunity is massive: a ~$1T+ revenue market hiding in plain sight. Our ambition is to build a $100B+ company by delivering a product that is fundamentally better—not incrementally improved. Flex has raised $100M+ in equity and $300M+ in debt.

Why Join Flex:

• Mission‑critical problems: We build software that directly controls how money moves at scale.
• High bar, low ego: Small teams, exceptional people, real ownership.
• Speed over comfort: We prioritize execution, quality, clarity, and results.
• Enduring impact: What we’re building will define how a generation of owners runs their businesses.

Team & Locations

We hire exceptional people who want to build hard things and see their work matter immediately. Roles are available in: San Francisco, Miami, New York, and fully remote.

About the Role

We're looking for a Software Engineer II to help build product features that power financial services. You'll work on systems that handle payments, credit, and other core products that our customers rely on daily to drive business operations.

What You’ll Do

• Own the full lifecycle of medium‑sized features and tasks across our product stack
• Build user‑facing features, internal tools, APIs, and backend services
• Write clear, maintainable, and tested code that you'll be responsible for long‑term
• Participate in code reviews and provide timely feedback to teammates
• Build features with the end product and user in mind, not just the code
• Reason carefully about how your work extends in service of larger product needs
• Build upon systems and features that others depend on
• Balance speed with reliability and compliance in a regulated environmentCollaborate with other engineers and product team members to deliver high‑impact work

What Makes You a Great Fit

• Have strong fundamentals in software development and ability to work effectively within established systems
• Product sense—you think about the user impact and business value of your work
• Ability to take responsibility for the maintenance and quality of what you build
• Experience with financial services, regulated industries, or handling sensitive data is a plus but not required
• Ability to research and proactively solve problems, bring solutions to the table
• English proficiency
• A strong work ethic

Technical environment

We primarily use Typescript, PostgreSQL, and GCP. We are building in a monorepo with a lean towards rapid value creation through trunk based development. Deploying to production 3–5 times a week is the average velocity of a team member.

What matters to us

We value ownership, product sense, and clear communication. You should be someone who thinks beyond just shipping code to understanding the impact on users and the business. We're a small team, so everyone wears multiple hats and jumps in where needed.

$110,000 - $145,000 a year

Why Join Us

Flex is growing quickly — you’ll help shape the direction of a product and company with real momentum.

We’re well‑capitalized with strong backing and a clear long‑term vision.

You’ll work with a sharp, driven team that values autonomy, clarity, and quality.

Join ambitious builders who care deeply about winning together — and having fun while doing it.

Annual team on‑sites. From Bogota to Mexico City, the entire Flex team gets together once a year to align and build camaraderie.