【AI × High-Growth SaaS / ¥8M~12M】Full Stack Lead Engineer / Global environemnt

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▶︎Overview

Position: Full Stack Lead Engineer

Salary: ¥7,000,000 – ¥12,000,000

Language: Japanese (N3 level required) / English (Nice to have)

Remote: Hybrid (Tokyo or Osaka)

▶︎About the Company

They are a rapidly growing AI-driven SaaS company providing enterprise-grade communication and marketing platforms. Their product enables businesses to optimize customer engagement through data-driven personalization, real-time messaging, and system integrations.

With strong backing and significant growth (over 10x in recent years), the company is expanding globally and building a multicultural engineering organization. Their mission is to empower brands by leveraging AI to create meaningful, long-term relationships with customers.

▶︎About the Role

As a Full Stack Lead Engineer, you will play a key role in driving the development of a high-traffic enterprise SaaS platform. You will work closely with the Tech Lead to make architectural decisions, improve development standards, and lead product evolution.

This role goes beyond implementation—you will contribute to product strategy, system design, and team growth while solving complex technical challenges in a fast-paced startup environment.

Key Responsibilities:

• Design, develop, and operate scalable full stack systems
• Improve and stabilize high-traffic infrastructure
• Develop new features aligned with the product roadmap
• Translate customer needs into scalable product features
• Lead technical decision-making and architecture design
• Collaborate with cross-functional and global teams

▶︎Development Environment

Backend: TypeScript (NestJS), Go, Elixir

Frontend: TypeScript (Next.js), Chakra UI

Database: TiDB, Aurora MySQL, DynamoDB, Redis

Infrastructure: AWS (ECS, Lambda, Kinesis, SQS, etc.), Terraform, AWS CDK

Monitoring: NewRelic, Sentry, CloudWatch

Data: BigQuery, Google Analytics, Metabase

Tools: Docker, GitHub Actions, Slack, Notion, Jira

AI Tools: GitHub Copilot, Cursor, Gemini, etc.

▶︎Position

Full-time employee (permanent)

▶︎Salary

Annual salary: ¥7,000,000 – ¥12,000,000

• Monthly: ¥585,000 – ¥835,000
• Includes fixed overtime (45 hours/month; excess paid separately)
• Final offer based on experience and skills

▶︎Qualifications

[Required]

• 5+ years of software development experience (TypeScript, Java, Go, or Python)
• Full stack development experience (frontend & backend)
• Strong JavaScript experience
• Experience delivering features end-to-end independently
• Code review experience (2+ years)
• Experience in technical decision-making and architecture design
• REST API design experience
• Business-level Japanese

[Preferred]

• Experience as a Tech Lead (leading teams of 5+)
• Experience with Go, Next.js
• Experience with DDD / Clean Architecture
• Experience with gRPC, CI/CD, AWS infrastructure
• Experience utilizing AI tools in development
• Business-level English

▶︎Work environment

• Hybrid work style (Tokyo or Osaka office + remote)
• Flexible working hours (core time: 10:00–16:00)
• Multinational, bilingual engineering team
• Engineering-driven culture with high autonomy
• Opportunities to lead architecture and product decisions

▶︎Holidays and Leave

• Weekends and national holidays
• Year-end/New Year holidays
• Summer vacation
• Paid leave (10 days from joining, increases over time)
• Special leave (bereavement, etc.)

▶︎Allowances and Benefits

• Transportation allowance
• Full social insurance
• Flexible start time system
• Health checkups covered
• Parental and childcare support
• Learning support (books, seminars)
• Club activities and internal programs

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