Senior Full Stack Software Engineer

Senior Full Stack Software Engineer

Location: Hong Kong

Job Highlights

• Build core fintech infrastructure — banking rails, crypto wallets, trading systems
• Full stack: React (web) + Node.js/PostgreSQL + AWS CDK + payments/crypto integrations
• 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, trading, custody, and digital assets. 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)
• Build and integrate crypto wallet infrastructure, including non-custodial wallet solutions, key management, and on-chain transaction handling
• 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
• Fluent in English

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)
• Familiarity with crypto wallets, key management, smart contracts (Solana or EVM chains), or DEX aggregators
• 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