Senior Software Engineer – Cloud Architecture & Tech Lead | FinTech Startup

One of our clients is looking for a Senior Software Engineer to lead the architecture and development of large-scale enterprise systems while remaining actively involved in hands-on software development. This is a senior technical position combining software architecture, technical leadership, cloud infrastructure, hands-on development, mentoring, and collaboration with business and technical stakeholders.

The position offers a flexible hybrid work style (4 times / week remotely). Annual salary: JPY 9,000,000 – 15,000,000, depending on experience and skills. International Engineering Environment / English used for technical communication. Japanese business level N2 (or equivalent) required. About the Company Our client is a technology company based in Tokyo providing software engineering and technology solutions to enterprise customers, with particular strength in the financial industry.

The company works on complex technology projects involving cloud-native architecture, backend and frontend systems, distributed systems, system modernization, and digital transformation for enterprise clients. The engineering environment is highly international, with engineers from a wide range of countries and backgrounds.

English is frequently used for technical discussions and collaboration within the engineering organization. Senior engineers have significant ownership over architecture, technology selection, engineering standards, and technical decision-making. About the Position As a Senior Software Engineer, you will take a leading role in the architecture, development, and technical direction of large-scale and complex software systems.

You will lead technical decisions across backend, frontend, and infrastructure while continuing to work directly on challenging development tasks. The role also includes technical leadership and mentoring responsibilities. You will support junior and mid-level engineers through code reviews, design reviews, technical guidance, and coaching.

You will work closely with Product Managers, business teams, client-side engineers, and other stakeholders to evaluate technical feasibility, explain architectural trade-offs, and deliver high-quality systems.

Key Responsibilities

Lead architecture design and technology selection for large-scale and complex systems Design solutions across backend, frontend, and infrastructure Lead cloud-native infrastructure design and implementation using AWS, GCP, and/or Azure Take ownership of technically challenging hands-on development tasks Lead software development while maintaining project schedules and engineering quality Develop and maintain high-quality systems, databases, and applications Work with Agile development methodologies such as Scrum and Kanban Define development guidelines, coding standards, testing strategies, and other engineering standards Conduct code reviews and architecture/design reviews Mentor and coach junior and mid-level engineers Support the technical development of other engineering team members Collaborate with Product Managers, business teams, and client-side development teams Clearly communicate technical feasibility, architectural decisions, and trade-offs to stakeholders Promote the effective use of Generative AI and emerging technologies within engineering processes Why Apply?

This position is particularly attractive for experienced engineers who want to take greater ownership of architecture and technical decision-making without moving away from hands-on development. Unlike positions that move senior engineers primarily into people management, this role allows you to continue solving complex technical challenges while acting as a technical leader for the broader engineering team.

You will have significant influence over architecture, technology selection, engineering standards, development practices, and technical quality. The role provides exposure to modern architecture patterns such as microservices, distributed systems, and event-driven architecture, as well as cloud-native environments across AWS, GCP, and Azure.

You will also work in a highly international engineering environment while contributing to complex enterprise systems and projects within the financial and Fin. Tech sectors.

Requirements

7+ years of professional experience as a Software Engineer, or equivalent demonstrated technical expertise Experience leading an engineering team as a Senior Engineer or Tech Lead, including experience leading a small team of approximately 3 or more engineers Deep knowledge and large-scale development experience with at least two of the following technologies: Spring (Java or Kotlin) Vue.

js / Nuxt.js / Quasar Go C# .NET / ASP.NET Advanced knowledge and hands-on infrastructure design experience with at least one of the following cloud platforms: AWS GCP Azure Practical experience with Infrastructure as Code, such as Terraform or Open. Tofu Experience designing modern architectures using at least one of the following patterns: Microservices Distributed Systems Event-Driven Architecture (EDA) Strong understanding of Computer Science fundamentals, Operating Systems, and the Software Development Life Cycle (SDLC) Ability to clearly explain architectural decisions, technical trade-offs, and design choices Ability to communicate technically in English within a multinational engineering team English reading and writing skills are required; conversational English is highly welcomed Nice to Have Experience developing systems within the financial or Fin.

Tech industry Experience with large-scale enterprise software development Experience working directly with clients, understanding their challenges, and proposing technical solutions Experience developing systems with high security standards and requirements, particularly within the financial industry Experience participating in products from early stages such as PoC or MVP development Experience introducing or operating Agile development methodologies such as Scrum or Kanban within engineering teams Experience mentoring junior and mid-level engineers Experience actively using Generative AI within software development or engineering processes Ideal Profile Strong technical engineer who wants to remain hands-on while taking ownership of architecture and technical leadership Able to make technology decisions while clearly understanding technical and architectural trade-offs Interested in both technical quality and the business impact of engineering decisions Comfortable mentoring and supporting the development of other engineers Able to handle complex and unexpected technical challenges as well as changing business requirements Comfortable collaborating with engineers from different cultures and backgrounds Strong communication and teamwork skills Interested in actively using Generative AI and emerging technologies to improve engineering productivity Comfortable working in a fast-moving environment with significant technical ownership Benefits Working Environment & Benefits Annual salary: JPY 9M – 15M Hybrid work: approximately 4 days remote per week Fully flexible working hours with no core time Full social insurance Maternity and childcare support Professional certification support Book and learning-material purchase support Appropriate development devices and equipment provided International engineering environment Frequent opportunities to collaborate with senior international engineers Opportunities to work on large-scale enterprise and financial-industry technology projects