Software Engineer (Full-Stack) | Japan-based

About Qompyl

Qompyl is an early-stage fintech startup building a mobile-first, hands-on, visual, and gamified strategy builder that empowers traders to create and refine trading strategies with ease. Our goal is to make advanced financial tools simple, intuitive, and accessible — closing the gap between complex market data and real decision-making.

We are a global, async-first, part-time team that values autonomy, clarity, collaboration, and thoughtful communication.

Learn more at qompyl.com

Role Overview

We’re looking for a Full-Stack Developer who can primarily lead back-end development while contributing to front-end features when needed. You’ll design and build scalable systems for a next-generation strategy-building platform, including high-performance APIs, real-time data services, and seamless integrations across the stack.

This is a part-time, equity-only role suited for someone seeking a meaningful side engagement alongside full-time work or consulting projects.

Key Responsibilities

• Design, develop, and maintain back-end systems using Python, FastAPI, SQLAlchemy, and PostgreSQL.
• Build and optimize RESTful APIs, WebSocket integrations, and real-time data services.
• Integrate financial data providers (Alpaca, Yahoo Finance, Alpha Vantage) for live and historical data.
• Improve performance across large datasets, strategy simulations, and live market flows.
• Contribute to front-end development using React and TypeScript.
• Participate in data modeling, schema design, and platform architecture.
• Build and maintain containerized applications using Docker and collaborate via Azure DevOps for pipelines and sprints.
• Maintain clear documentation, code quality, and Git/GitHub workflows in a global async-first environment.
• Foster a healthy, respectful, and collaborative team culture.

Requirements

• Strong experience with Python, FastAPI, SQLAlchemy, and relational databases (PostgreSQL preferred).

• Familiarity with Pydantic, RESTful API design, WebSockets, and real-time data patterns.

• Exposure to React and TypeScript for occasional front-end contributions.

• Ability to integrate external APIs and work with financial data providers.

• Solid understanding of Git, documentation practices, and collaborative workflows.

• Experience with Docker; familiarity with CI/CD or Azure DevOps is a plus.

• Understanding of mobile application architecture principles (mobile-first, performance, state management); exposure to Flutter or mobile-backend integration is a strong plus.

• Comfortable working in a remote, async, high-ownership environment.

• Curious, adaptable, and motivated to build tools that simplify complex workflows.

💡 Please Note - Equity-Only Structure

This is a part-time, equity-only role, suitable as a side engagement alongside a primary job or consulting work.

The position will transition to compensated status after the MVP launch and once funding or sustainable revenue is secured.

If you're excited about joining an early-stage mission-driven startup and helping build a next-generation trading platform, we’d love to hear from you.