Company Overview

The company operates a marketing SaaS platform leveraging LINE. As a rapidly growing startup, it utilizes AI technologies to help brands build sustainable and trustworthy relationships with their customers.

In addition to its LINE marketing tools, the company develops and provides a range of services, including LINE 1-to-1 business chat, digital membership card LINE mini apps, and AI-powered call solutions.

■Key Features

• Operates in the C-commerce market, which is estimated to be worth nearly JPY 30 trillion globally and is projected to surpass the e-commerce market in certain countries by 2025
• Achieved 760% business growth over the past three years in the marketing SaaS domain
• Successfully raised a total of JPY 6.3 billion in funding (including JPY 3.5 billion in Series B)
• Ranked No.1 in LINE marketing in Japan
• A global organization with offices overseas and team members representing 20 different nationalities

 

About the Role

This position focuses on the development of the company’s AI-native customer engagement platform. The platform helps businesses build meaningful relationships with their customers through messaging automation, real-time communication, and AI-powered interactions.

As a Full Stack Lead Engineer, you will lead the design and development of systems across both the frontend and backend of the company’s products. Beyond hands-on implementation, you will provide technical leadership across a broad range of areas, including architectural decision-making, mentoring, and operational improvements.

Working closely with the Product, Design, AI, and Infrastructure teams, you will help deliver scalable, intuitive customer engagement experiences for enterprise customers in Japan and beyond.

Key Responsibilities

• Lead the design and development of scalable frontend and backend systems that power Mico Message.
• Build and improve customer-facing applications and internal operational tools.
• Design robust APIs, backend services, and platform integrations.
• Drive technical decision-making and contribute to system architecture discussions.
• Work closely with Product and Design teams to shape product direction and user experience.
• Continuously improve system reliability, scalability, performance, and operational observability.
• Write maintainable, well-tested code following modern engineering practices.
• Establish and improve engineering standards, development workflows, and technical processes.
• Mentor and support engineers through code reviews, technical guidance, and knowledge sharing.
• Troubleshoot and resolve complex production incidents in distributed systems.
• Communicate effectively across functions in both Japanese and English.
• Take end-to-end ownership of projects, from requirements definition through production deployment and operation.

Expectations for This Role

• Enjoy solving complex technical and product challenges while balancing development speed with long-term maintainability.
• Communicate effectively with both technical and non-technical stakeholders.
• Work autonomously and collaborate effectively in a distributed, remote-first environment.
• Take meaningful ownership of system architecture and product direction.
• Actively contribute to shaping the engineering culture and technical standards.

What This Role Offers

• Meaningful Impact: Help shape the future of AI-powered customer engagement.
• Technical Influence: Have a significant voice in architecture, engineering standards, and product direction.
• Ownership and Autonomy: Work in an environment that encourages independent decision-making and end-to-end ownership.
• Global Engineering Culture: Join a collaborative, global, remote-first engineering team.
• Continuous Growth: Access ongoing learning opportunities and professional development.
• Competitive Compensation: Receive competitive compensation and benefits.
• Flexible Working Environment: Enjoy flexibility built on mutual trust and accountability.

Career Development Opportunities

• Technical Leadership and Architecture: Deepen your expertise as an engineering lead and progress toward an Architect or senior technical leadership role.
• Engineering Management / CTO Track: Expand your involvement in product and business decisions and pursue a career in engineering management or toward a CTO role.
• Global Engineering Leadership: Progress into a key leadership position within a global engineering organization.

Requirements

Required Qualifications

• 5+ years of professional experience as a software engineer.
• Experience working with Agile and Scrum development processes.
• Business-level or higher proficiency in English.
• Conversational proficiency or higher in Japanese.
• Strong full-stack development experience building modern web applications.
• Frontend development experience using technologies such as React, Vue, or Next.js.
• Backend development experience using technologies such as Node.js, Python, Elixir, Ruby, or PHP.
• Experience designing scalable APIs and backend systems.
• Deep understanding of software architecture, system design, and technical trade-offs.
• Experience working with relational databases such as PostgreSQL or MySQL.
• Experience developing and operating production systems, with responsibility for their ongoing operation.
• Experience mentoring engineers or leading technical projects.
• Strong communication, debugging, collaboration, and problem-solving skills.
• Ability to take initiative and drive challenges forward in uncertain or ambiguous situations.

Preferred Qualifications

• Experience with typed languages or type systems, such as TypeScript or Python type hints.
• Experience with gRPC and Protocol Buffers.
• Experience with Elixir/Phoenix or functional programming.
• Experience developing scalable SaaS platforms.
• Understanding of conversational AI and applications powered by large language models (LLMs).
• Experience designing event-driven architectures and distributed systems.
• Experience collaborating closely with Infrastructure or DevOps teams.
• Experience improving development processes and engineering workflows.
• Experience working at a rapidly growing startup.
• Interest in AI-assisted software development workflows.

Ideal Candidate Profile

• Enjoys solving complex technical and product challenges.
• Balances rapid delivery with long-term maintainability.
• Communicates effectively with both technical and non-technical stakeholders.
• Works independently and collaboratively in a distributed team environment.
• Wants to take meaningful ownership of system architecture and product direction.
• Is eager to contribute to and shape the engineering culture.

 

Compensation & Benefits

Salary: JPY 7,000,000 〜JPY 11,000,000per year
Probation Period: 3 months

Location
The position is based in either Tokyo or Osaka, depending on the candidate’s preference. Fully remote arrangements can be discussed on a case-by-case basis.

The company offers a flexible hybrid work style, combining remote work with office attendance. Frequency of office visits varies, typically ranging from once a week to once a month.

Working Hours

• Standard hours: 9:00 AM – 6:00 PM (includes a 1-hour break; overtime may be required)
• Flexible working hours with core time from 10:00 AM – 4:00 PM
• For employees above a certain grade, a discretionary labor system applies according to company policy

Holidays & Leave

• Saturdays, Sundays, and public holidays
• New Year’s holidays
• Summer vacation
• Bereavement leave
• Paid leave (10 days granted upon joining, with additional days accrued based on length of service)
• Other holidays as specified by company regulations

Benefits & Perks

• Commuting allowance (bicycle commuting permitted)
• Company-provided laptop
• Company-provided mobile phone (for certain roles only)
• Flexible start time program (can be applied for every 2 months)
• Social insurance coverage (health insurance, employee pension, employment insurance, workers’ compensation)
• Life & health support leave
• Coverage of medical check-up expenses
• Childbirth and childcare support programs
• Club activities and social groups

Measures Against Secondhand Smoke: No Smoking Indoors

 

Hiring Process

• Number of interviews: 3
• Application documents required: Resume / CV
• Interview language: Japanese and English

 

Please note: this position is open to candidates currently residing in Japan.