About the role

In partnership with SBI Group, we are building a next-generation decentralized exchange (DEX) aimed at bringing the majority of Japanese equities on-chain. Our goal is to create a secure, transparent, and high-performance trading infrastructure capable of supporting institutional volumes while remaining accessible to retail participants. The platform features a fully on-chain order book and is powered by a custom state transition function and consensus layer, purpose-built for low-latency, high-throughput trading.

As the Senior QA Engineer, you will be the quality champion for this system and cover core trading flows, order book behavior, matching logic, and backend services powering execution. As the first senior-level QA on the team, you will own the end-to-end quality strategy with a strong emphasis on automation, ensuring the correctness, reliability, and performance of both API and E2E layers under real-world trading conditions.

This is a hands-on role focused on building robust E2E and API test coverage, not manual testing.

Key responsibilities

• Quality strategy & process: Define and evolve QA standards, release criteria, and quality metrics tailored to a trading platform. Establish best practices for validating execution accuracy, pricing, and API reliability.

• Automation (E2E-first approach):

  Design, build, and maintain a scalable end-to-end automation framework for the web app, covering critical user journeys.

• API testing & validation:

  Develop comprehensive automated tests for backend services and APIs. Ensure consistency between API responses and frontend behavior.

• Trading logic validation:

  Validate correctness of execution paths, price impact, and fee calculations across different trading pairs and liquidity sources.

• Performance & reliability:

  Drive API-level load and stress testing for high-throughput scenarios. Validate system behavior under peak traffic and degraded conditions (timeouts, partial failures, node issues).

• Test data & environment strategy:

  Design reliable test environments and datasets (mocked or real blockchain interactions), ensuring repeatability of E2E and API tests.

• Cross-team collaboration & leadership:

  Work closely with Engineering and Product to define testable acceptance criteria. Take ownership of QA processes, drive automation adoption, and set quality standards across the team.

Qualifications

Required experiences

• 3+ years in QA for web or fintech products, with at least 2+ years focused on test automation and E2E testing.
• Strong experience building and maintaining E2E test frameworks (e.g. Playwright, Cypress, or similar).
• Solid experience in API testing and automation (REST, JSON-RPC, or similar).
• Strong JavaScript/TypeScript skills.
• Experience testing complex transactional or financial systems.
• Good understanding of trading concepts: slippage, liquidity, routing paths, execution flow.
• Experience designing stable, maintainable automated test suites (CI integration, flakiness reduction).

Nice-to-have

• Experience testing DEXs, trading platforms, or financial systems.
• Familiarity with blockchain basics, smart contracts, and on-chain transaction flows.
• Understanding of AMMs, liquidity pools, and routing algorithms.
• Experience with performance/API load testing tools (e.g. k6, Artillery).
• Experience using AI tools to improve test generation and coverage.

About the role

You will be a senior contributor to our frontend product experience, working across our product suite, including our self-custodial wallet interfaces, account abstraction user flows, and a growing set of web and mobile decentralized applications (dApps). As a senior frontend engineer on the team, you will help shape frontend architecture, deliver complex user-facing features, and embed performance, reliability, and usability best practices into every release.

You will work closely with designers, product managers, and engineers to take features from concept to production, while contributing to improving code quality, system design, and team workflows.

Key responsibilities

Frontend architecture & technical contributions: Contribute to the evolution of frontend system design, patterns, and best practices.

Application development: Design, build, and maintain complex, production-grade frontend applications using TypeScript and TanStack Start.

State management & data orchestration: Implement and maintain scalable client-side state using Zustand and TanStack Query to ensure predictable and performant data flows.

Project ownership: Own and deliver end-to-end frontend workstreams, including:

• Core wallet and account abstraction UX flows
• High-throughput, data-rich product interfaces
• New web and mobile dApp surfaces

Testing & reliability: Contribute to and maintain Playwright-based end-to-end test suites to improve coverage and release confidence.

Cross-functional collaboration: Partner with Product, Design, and Backend teams to refine requirements and deliver high-quality outcomes.

Qualifications

Required experience

• 2 ~ 4 years of experience as a frontend engineer
• Strong proficiency in TypeScript and modern JavaScript.
• Experience with TanStack Start or comparable meta-frameworks (e.g., Next.js, Remix).
• Solid expertise in modern React patterns, performance optimization, and frontend application design.
• Ability to operate independently in ambiguous, fast-paced environments.
• Excellent written and verbal communication skills.

Nice-to-have

• Experience leveraging AI-assisted coding tools (Cursor, Copilot, Claude, or similar) to accelerate development.
• Background in web3, blockchain, or decentralized application development.
• Experience in startup or scale-up environments.

Location and logistics

• East Asia preferred (Tokyo, Singapore, HongKong)