Staff Fullstack Engineer

Nium is seeking a Staff Fullstack Engineer for their Customer Experience team in San Francisco. This role involves evolving fast prototyping culture, owning the application stack from discovery to customer revenue, and building user-facing features with React, TypeScript, and Next.js. The engineer will also develop and integrate REST APIs using Java Springboot or Node.js, maintain clean code, contribute to architectural decisions, and optimize for performance and accessibility. The position requires 5+ years of web application experience and strong skills in JavaScript, TypeScript, React, CI/CD, DevOps tools, structured programming languages, and backend concepts.

Must Have

• Help evolve fast prototyping culture to foster innovation and quick market validation.
• Take ownership of the entire application stack through discovery & validation to customer revenue cycle.
• Build user-facing features using React, TypeScript, and Next.js.
• Develop and integrate REST APIs using Java Springboot or Nodejs based technologies.
• Maintain clean, modular, and well-tested code across the stack.
• Contribute to architectural decisions, code reviews, and shared components.
• Optimize for performance, accessibility, and responsiveness.
• 5+ years of experience building web applications in production environments.
• Strong knowledge of JavaScript / TypeScript and React.
• Strong focus on Reliability and scalability of applications.
• Exposure to CI/CD and DevOps tools (Docker, feature flags, monitoring).
• Strong fundamentals in structured programming languages (Java/GoLang/C).
• Experience integrating with REST APIs and backend systems.
• Solid understanding of frontend fundamentals (HTML/CSS, accessibility, testing).
• Familiarity with backend concepts (Java/Spring Boot, SQL, containers).

Good to Have

• Experience with large-scale design systems.
• Cyber Security experience.
• Experience tuning frontend performance (lazy loading, bundle size, etc.).
• Interest in fintech or global payment systems.

Perks & Benefits

• Competitive salaries
• Performance bonuses
• Sales commissions
• Equity for specific roles
• Recognition programs
• Medical coverage
• 24/7 employee assistance program
• Generous vacation programs including year-end shut down
• Flexible hybrid working environment (3 days per week in the office)
• Role-specific training
• Internal workshops
• Learning stipend
• Company-wide social events
• Team bonding activities
• Happy hours
• Team offsites

About Nium

Nium is the leading global infrastructure for real-time cross-border payments. We were founded on the mission to deliver the global payments infrastructure of tomorrow, today. Our platform enables banks, Fintechs, and global businesses to move money instantly, everywhere.

Co-headquartered in San Francisco and Singapore with offices in 14 markets worldwide, we are entering one of the most exciting chapters in our journey. In July 2025, we delivered the largest month in our 10-year history with record revenue, record volumes, and EBITDA profitability. Today, Nium moves nearly $50B in payments annually, almost entirely for enterprises, while continuing to strengthen an already healthy balance sheet.

It is an incredible time to join us, and we are only just getting started.

Our payout network spans 190+ countries and 100 currencies, with 100 corridors in real time. We power seamless transfers to accounts, wallets, and cards, support local collections in 35 markets, and run a card issuance business live in 34 countries. Backed by regulatory licenses in more than 40 markets, we make it simple for our partners to onboard, integrate, and scale globally. This scale and innovation have earned us recognition as one of CNBC’s World’s Top Fintech Companies 2025, winner of Best Cross-Border Payments Solution at the PayTech Awards, and inclusion in FXC Intelligence’s Top 100 Cross-Border Payments Companies list.

In 2024, we raised US$50 million in Series E funding at a US$1.4 billion valuation to accelerate network expansion, product innovation, and talent growth. With the B2B payments market projected to hit US$175 trillion by 2030, Nium offers ambitious builders the chance to shape the future of global money movement with the scale of a leader and the energy of a high-growth company.

About the Team

The Customer Experience team in San Francisco office builds and owns the GoTo Market strategy for various products that take Nium’s market offerings forward using our core banking infrastructure rails. New initiatives include partner integrations for stablecoins, growth in FX and payroll segment verticals, hosted onboarding and taxes for talent marketplaces and seamless Direct Debit support for PayIns.

The team has rolled out properties like the Nium Client Portal, the central self-service web platform for accessing Nium’s global payments infrastructure and seeks to expand our offerings further for supporting our Hypergrowth phase.

Nium Portal is the single entry point for clients to:

• Create and manage virtual accounts
• Send real-time cross-border payouts
• Issue cards and track balances
• View transactions, FX rates, and reporting dashboards
• Monitor compliance, onboarding, and KYC/KYB workflows

Our users include fintech developers integrating APIs, as well as operations teams managing high-volume financial workflows. We focus on delivering seamless user experiences and building products that balance self-serve simplicity with deep operational power.

Our goal is to turn complex payment infrastructure into a product experience that is intuitive, scalable, and flexible. As we expand into new markets and product lines, we are investing heavily in frontend engineering, fullstack capabilities, and product velocity to better serve our customers.

Our Stack

Frontend: React, TypeScript, Next.js, Tailwind CSS, SWR, Cypress, D3, AG Grid

Backend: Java, Spring Boot, PostgreSQL, REST APIs

Tooling: Docker, CI/CD pipelines, Datadog, LaunchDarkly

Responsibilities

• Help evolve our fast prototyping culture to foster innovation and quick market validation.
• Take ownership of the entire application stack and take us through the entire discovery & validation to the customer revenue cycle.
• Build user-facing features using React, TypeScript, and Next.js.
• Develop and integrate REST APIs using Java Springboot or Nodejs based technologies.
• Maintain clean, modular, and well-tested code across the stack.
• Contribute to architectural decisions, code reviews, and shared components.
• Optimize for performance, accessibility, and responsiveness.

Requirements

• 5+ years of experience building web applications in production environments.
• Strong knowledge of JavaScript / TypeScript and React.
• Strong focus on Reliability and scalability of applications.
• Exposure to CI/CD and DevOps tools (Docker, feature flags, monitoring).
• Strong fundamentals in structured programming languages (Java/GoLang/C).
• Experience integrating with REST APIs and backend systems.
• Solid understanding of frontend fundamentals (HTML/CSS, accessibility, testing).
• Familiarity with backend concepts (Java/Spring Boot, SQL, containers).
• Clear, effective communication and collaboration skills.
• Growth mindset — you ask questions, give feedback, and enjoy learning.

Nice to have

• Experience with large-scale design systems.
• Cyber Security experience.
• Experience tuning frontend performance (lazy loading, bundle size, etc.).
• Interest in fintech or global payment systems.

What we offer at Nium

We Value Performance: Through competitive salaries, performance bonuses, sales commissions, equity for specific roles and recognition programs, we ensure that all our employees are well rewarded and incentivized for their hard work.

We Care: The wellness of Nium’ers is our #1 priority. We offer medical coverage along with 24/7 employee assistance program, generous vacation programs including our year-end shut down. We also provide a flexible hybrid working environment (3 days per week in the office).

We Upskill Ourselves: We are curious, and always want to learn more with a focus on upskilling ourselves. We provide role-specific training, internal workshops, and a learning stipend.

We Constantly Innovate: Since our inception, Nium has received constant recognition and awards for how we approach both our business and talent opportunities. Check out CNBC World’s Top Fintech Companies 2024.

We Celebrate Together: We recognize that work is also about creating great relationships with each other. We celebrate together with company-wide social events, team bonding activities, happy hours, team offsites, and much more!

We Thrive With Diversity: Nium is truly a global company, with more than 33 nationalities, based in 18+ countries and more than 10 office locations. As an equal opportunity employer, we are committed to providing a safe and welcoming environment for everyone.

For more detailed region-specific benefits: https://www.nium.com/careers#careers-perks

For more information visit www.nium.com

Depending on your location, certain laws may regulate the way Nium manages the data of candidates. By submitting your job application, you are agreeing and acknowledging that you have read and understand our Candidate Privacy Notice located at www.nium.com/privacy/candidate-privacy-notice.

For more information, visit www.nium.com.

Nium provides equal employment opportunities (EEO) to all employees and applicants for employment without regard to race, color, religion, gender, sexual orientation, national origin, age, disability, or veteran status. In addition to federal law requirements, Nium complies with applicable state and local laws governing non-discrimination in employment in every location in which the company operates. This policy applies to all terms and conditions of employment, including recruiting, hiring, placement, promotion, termination, layoff, recall, transfer, leaves of absence, compensation, and training. Nium expressly prohibits any form of workplace harassment based on race, color, religion, gender, sexual orientation, national origin, age, disability, or veteran status.

We may use artificial intelligence (AI) tools to support parts of the hiring process, such as reviewing applications, analyzing resumes, or assessing responses. These tools assist our recruitment team but do not replace human judgment. Final hiring decisions are ultimately made by humans. If you would like more information about how your data is processed, please contact us.