Senior Full Stack Software Engineer
Summary
Senior full stack engineer at a Hong Kong fintech building mission-critical payments infrastructure for institutional clients. Day to day: build web and backend features in TypeScript, Node.js, React, and PostgreSQL, integrate banking rails (ACH, FPS, SWIFT), implement auth/security (OAuth, WebAuthn, passkeys), and deploy AWS infrastructure as code.
- 5+ years engineering experience with fintech or financial systems
- We're looking for someone who can start within the next 1 month.
About Us
We are a Hong Kong-based fintech company building mission-critical financial infrastructure across payments. This is an opportunity to work on core platform systems that handle real-time transactions and serve institutional clients. We value engineers who take ownership, ship with urgency, and care deeply about building secure, reliable financial systems.
Responsibilities
- Develop and maintain full stack features across web and backend services (Node.js, PostgreSQL) powering the company's fintech platform
- Integrate fiat banking rails and payment infrastructure including ACH, card issuing, ledger systems, and real-time payment networks (e.g., FPS, SWIFT)
- Implement authentication and security solutions including passkeys, device biometrics, OAuth, WebAuthn, and session management to protect client assets and data
- Design and consume REST APIs; build robust, well-documented service interfaces for internal and external consumption
- Participate in architecture decisions shaping system scalability, security, fault tolerance, and user trust across the platform
- Define and deploy cloud infrastructure using AWS CDK, applying infrastructure-as-code practices for reproducible, auditable, and version-controlled deployments
- Champion engineering best practices including code reviews, automated testing, CI/CD pipelines, observability, and comprehensive documentation
- Mentor junior and mid-level engineers; contribute to technical hiring and building the engineering team culture
Requirements
- Bachelor's or Master's degree in Computer Science, Software Engineering, or a related field, or equivalent professional work experience
- Minimum 5 years of professional full stack engineering experience, with demonstrated work on financial or fintech systems
- Strong proficiency in TypeScript, Node.js, and React; experience with PostgreSQL or equivalent relational databases
- Experience designing and consuming REST APIs in production environments
- Hands-on experience with AWS and infrastructure-as-code tooling
- Solid understanding of authentication models (OAuth, WebAuthn, session security) and security best practices for financial applications
- Proven ability to work effectively with AI coding agents and to critically review the code and changes they produce
- Self-starter with strong ownership mentality who thrives in ambiguous, fast-paced environments; comfortable proposing solutions and driving them to completion
Preferences
The following are not required, but candidates with any of these will stand out:
- Familiarity with AWS CDK specifically
- Experience with fintech or payments APIs (e.g., Stripe, Plaid, Marqeta, Column, Lithic, Unit) or banking integration (ACH, card networks, ledger systems)
- Fluency in native iOS (Swift) and/or native Android (Kotlin) development
- Proficiency in Cantonese and/or Mandarin
Hiring Process
Candidates progress through the following stages and must pass each one to advance to the next:
- Programming screening — an unproctored multiple-choice test covering core programming fundamentals
- Technical interviews — two live interviews (no coding) of similar content, each conducted by a different interviewer, building on the candidate's screening answers and covering software engineering fundamentals and problem-solving