Javascript Backend Developer Jobs in Fairfield, NJ

WHY WE EXIST

Money should move as easily as data.

It doesn't today. Technology is finally catching up to the need — customers expect instant, global, programmable money. HIFI exists to fix that. Our mission is to make money programmable by default, and to give developers and businesses the tools to move value at software speed.

We're rebuilding the financial plumbing of the internet from the ground up.

THE ROLE

As a Senior Backend Engineer at HIFI, you'll own critical components of our payments infrastructure — from API design and data modeling to event-driven pipelines and financial-grade reliability. You'll work across the full lifecycle of modern money movement: account creation, fiat and stablecoin settlement, global payouts, and onchain connectivity.

This is not a maintenance role. You'll solve hard, novel problems at the edge of what's possible in financial infrastructure, move fast, own your systems end-to-end, and directly shape how billions of dollars flow through the internet.

If you touch it, you own it. That's how we work.

WHAT YOU'LL BUILD

• API Development: Design, implement, and optimize APIs that connect businesses to
  HIFI’s financial infrastructure platform, with a focus on performance, reliability, and
  developer experience.

• Core Infrastructure: Build and scale backend systems that process transactions,
  ensure correctness, and provide strong guarantees around scalability, reliability, and
  fault tolerance.

• System Performance: Continuously improve throughput, efficiency, and resilience
  across distributed services.

• Collaboration: Work closely with product, compliance, and business teams to deliver
  end-to-end solutions.

• Ownership: Participate in technical roadmap planning and carry projects from design
  through production.

• User Focus: Engage with customers to understand their needs and translate them into
  effective solutions.

WHAT WE'RE LOOKING FOR

• Bachelor’s degree in Computer Science, Engineering, Math, or related STEM field, or
  equivalent practical experience.

• 2+ years of professional software development experience.

• Proficiency in one or more programming languages (JavaScript/TypeScript with Node.js,
  Go, Python, etc.).

• Experience working with RESTful APIs.

• Experience with PostgreSQL or other relational databases.

• Familiarity with cloud platforms (AWS, Azure, or GCP) and containerization technologies
  (Docker, Kubernetes).

• Working knowledge of version control (Git), CI/CD pipelines, testing, and
  monitoring/observability tools.

• Strong communication and collaboration skills with both technical and non-technical
  teams.

NICE TO HAVE

• Knowledge of query optimization and database performance tuning.

• Familiarity with concurrency control, distributed systems, and database transactions.

• Experience working on distributed systems and optimizing them for scalability and
  performance.

• Familiarity with event-driven architectures and messaging patterns (e.g., pub/sub,
  queues, streaming).

• Exposure to job queues, caching services, and data pipelines.

• Understanding of security best practices and a commitment to correctness in financial
  systems.

• Experience building and launching a product from zero to one.

• Background or interest in financial systems, payments, or blockchain/crypto technologies
  is a plus.

THE HIFI CODE

This is how we operate. Not aspirational — actual.

Ownership If you touch it, you own it.

Speed We bias toward motion.

Clarity Confusion is a signal to act.

Standards Quality matters always.

Truth We value directness without drama.

COMPENSATION & BENEFITS

The expected salary range for this role is $135,000 - $160,000 USD. However, the starting base pay will depend on a number of factors including the candidate’s location, skills, experience, market demands, and internal pay parity. Depending on the position offered, equity and other forms of compensation may be provided as part of a total compensation package.

We offer full health coverage (medical, dental and vision) and unlimited PTO.

We're changing how modern business moves value.

If that sounds like the problem you want to spend the next chapter of your career on, we'd love to meet you.

EQUAL OPPORTUNITY STATEMENT

HIFI is an equal opportunity employer. We do not discriminate on the basis of race, color, religion, sex, sexual orientation, gender identity, national origin, age, disability, veteran status, or any other legally protected status. We also provide reasonable accommodations during the hiring process.

By submitting your application, you acknowledge that HiFi will process your personal information in accordance with our Applicant Privacy Policy.

Compensation Range: $135K - $160K