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 Data Platform Team

Established in May 2026, the Data Platform Team is dedicated to building and evolving the data infrastructure that powers the company’s AI products.

As the business has grown rapidly, the data models supporting its products have become increasingly complex. The team’s mission is not simply to conduct a one-time review or cleanup of existing data models, but to establish sustainable data governance capabilities that continuously improve and deliver compounding value over time.

The Lead Data Engineer will define the team’s technical direction and roadmap and drive execution. This role goes beyond database operations and performance tuning to encompass data model redesign and strategic decisions about how responsibilities should be divided between TiDB and Snowflake.

Key areas of responsibility include:

• Prioritizing the development of the governance foundation and defining clear completion criteria
• Establishing a decision-making framework for data tiering and storage selection between TiDB and Snowflake
• Designing an overall architecture for reducing database load
• Leading the next-generation redesign of customer and segment data models
• Upholding engineering discipline by ensuring that decisions are based on measurement and documented evidence, while clearly communicating the rationale to business stakeholders

Why This Role Is Open

The company has achieved 1,100% business growth over four years in the marketing SaaS sector, and the data models supporting Mico Engage AI have expanded alongside the business.

To support the next stage of growth, the Data Platform Team was established in May 2026 as a dedicated team responsible for data model design and storage strategy.

The overall technical direction has been established. The immediate priority is to build a reliable foundation for validation and measurement, using the resulting evidence to guide decisions on data tiering and data model redesign. However, many of the details still need to be established, including completion criteria for the governance foundation, the framework for tiering decisions, and the redesign of core entities.

The team currently consists of senior members based in Japan, led by a Senior Tech Lead, alongside team members based in India. However, the team does not yet have sufficient engineering capacity to design and execute all the initiatives required to strengthen the data platform. An additional technical leader is needed to help drive this work.

Once the data foundation is in place, the company will be better positioned to continuously deliver customer-facing capabilities such as customer data platform (CDP) functionality and recommendation systems.

The goal is to bring in a technical leader who can drive decisions and redesign initiatives into execution while maintaining and advancing the team’s 12-month roadmap.

Key Responsibilities

This position combines hands-on Database Reliability Engineering (DBRE) with technical leadership that influences both team execution and business decisions.

1. Database Reliability Engineering: Hands-On Responsibilities

Database Performance and Capacity Optimization

• Improve query execution plans and address locking issues across Aurora MySQL and TiDB.
• Manage schema changes on large tables using approaches such as gh-ost, pt-online-schema-change (pt-osc), and Online DDL.
• Drive performance and capacity improvements based on benchmarks and quantitative evidence.

Governance Foundation Design and Prioritization

• Design and prioritize the foundational capabilities required for effective data governance, including data lineage, test reliability, benchmarking, data classification, architecture decision records (ADRs), local reproduction environments, and collaboration with external experts.
• Define minimum viable standards and validate their effectiveness through real-world projects.
• Establish clear boundaries to avoid both overengineering and insufficient implementation.

End-to-End Database Load Reduction

• Design the overall architecture and migration sequence for initiatives such as retention-based data deletion, event attribute enrichment, offloading heavy aggregation workloads to Snowflake, and reverse ETL.
• Lead the implementation of these initiatives.

Incident Command and Systematic Prevention

• Lead incident response and drive root cause analysis (RCA) through to the implementation of systematic preventive measures.
• Turn every incident into an opportunity to identify and implement improvements to the underlying systems and processes.

Hands-On Engineering

• Personally design and implement solutions for the most technically challenging areas and when establishing new systems.
• Set engineering standards through code and implementation practices.

2. Technical Leadership: Driving the Team and Business

Maintaining and Evolving the Technical Direction and Roadmap

• Maintain and update the existing 12-month roadmap, reviewing phases, exit criteria, dependencies, and critical paths on a quarterly basis.
• Clearly distinguish firm commitments from longer-term directions that remain subject to validation.

Establishing a Data Tiering and Storage Decision Framework

• Establish a framework for determining which entities should remain in TiDB and which should be moved to Snowflake, based on data classification and lineage.
• Make this framework the default approach for evaluating new requirements.

Leading the Next Generation of Data Models

• Lead the redesign of customer and segment data models using a profiling-first approach: establish an accurate understanding of the current data and supporting evidence before deciding on the target design.
• Establish a traceable chain of evidence: classification, lineage, and benchmarking → decision → documentation.

Building Alignment with Business Stakeholders

• Explain the impact and risks of changes requiring business stakeholder involvement, such as retention-based data deletion and migration to new segment definitions.
• Communicate technical considerations in terms that non-engineers can understand and build agreement on implementation priorities and sequencing.

Designing and Managing External Expert Collaboration

• Establish regular technical reviews with database and data warehouse vendors.
• Centralize communication channels, define escalation paths, and ensure that key decisions are documented.

Team Development and Recruitment

• Mentor and develop team members at senior level and below.
• Design onboarding processes and contribute to recruitment.
• The scope of people management can be discussed based on the candidate’s interests and the organization’s needs.

Expectations for This Role

• Design the governance foundation and data tiering decision framework, involving the team and relevant departments to put them into practice.
• Maintain the 12-month roadmap, conduct monthly reviews, and deliver outcomes on a quarterly basis, while avoiding premature commitments on the scope and timelines of initiatives that are not yet sufficiently understood.
• Manage database capacity planning, data retention and expiration schedules, and infrastructure costs quantitatively, establishing clear accountability and the ability to explain the situation to executive leadership.
• Uphold engineering discipline by consistently requiring validation and measurement, even when faced with pressure around priorities or delivery deadlines.
• Build and maintain data lineage, runbooks, and decision records so that governance capabilities remain sustainable even as team members change.

What This Role Offers

Autonomy to Build on an Established Technical Direction

The overall principles and direction are in place, but much of the implementation framework remains to be defined, including governance completion criteria, data tiering decisions, and the redesign of core entities. This role offers the opportunity to shape these foundations and put your own technical judgment into practice.

Direct Influence on Product and Business Growth

Decisions about where data entities should reside and which models should be redesigned will directly influence the scalability of the business and the range of future product capabilities.

Direct Engagement with Business and Executive Leadership

You will have opportunities to explain database capacity, retention policies, and migration costs in your own words, helping business stakeholders understand trade-offs and secure the cooperation and resources needed for implementation.

Structured Collaboration with Leading Vendor Engineers

You will help establish sustainable collaboration models with database and data warehouse vendors, moving beyond ad hoc support toward a structured approach to technical reviews, escalation, and decision-making.

Global Technical Leadership Experience

Working within a multinational team where English is used alongside Japanese, you will lead technical initiatives, team development, and engineering standardization, building leadership experience that is valuable in global engineering organizations.

Career Development Opportunities

• Data Platform Tech Lead / Engineering Manager: Progress toward managing the broader Data Platform organization, building on experience in team leadership and talent development.
• Chief Data Architect / Principal Engineer: Pursue a deeper technical career focused on defining data architecture across the company without moving into people management.
• Cross-Platform Technical Lead: Expand your scope to lead technical initiatives across multiple platform domains.
• VP of Engineering / CTO Track: Build toward an executive-level role by developing a track record in both technical strategy and organizational design.

Technology Stack

• Application: TypeScript / Node.js (monorepo)
• Databases: Aurora MySQL, TiDB, and Aurora PostgreSQL for selected services. Aurora MySQL and TiDB will continue to be used in parallel.
• Data Warehouse: Snowflake
• Cloud: AWS

 

Requirements

Required Experience

Candidates should have hands-on experience designing and operating production MySQL-based relational database management systems (RDBMS), such as Aurora MySQL, TiDB, or MySQL, typically for at least three years. They should also have approximately two or more years of experience making technical design decisions as a Tech Lead or Architect.

In addition, the following experience is required.

Database Engineering Fundamentals

Deep Operational Expertise in MySQL-Based RDBMS

• Practical experience improving query execution plans, addressing locking issues, and managing DDL operations on large tables using approaches such as gh-ost, pt-osc, and Online DDL in Aurora MySQL, TiDB, or similar systems.
• Ability to assess and communicate database capacity and scalability limits quantitatively.
• Experience with environments where Aurora MySQL and TiDB are used in parallel is particularly relevant.

Relational Data Modeling

• Practical experience designing entities, making normalization and denormalization decisions, designing indexes, and defining transaction boundaries.

Experience Required for Technical Leadership

Data Model Modernization in Live Systems

• Experience designing and leading data model or schema modernization in large, live production systems and completing migrations without service downtime.
• Ability to design migration strategies involving dual writes, backfills, and gradual cutovers.
• In this role, you will lead the next-generation redesign of customer and segment data models.

Technical Decision-Making as a Tech Lead or Architect

• Experience owning team-level design decisions, including defining engineering standards and ensuring their adoption across the team.

Language Proficiency

• Fluent or higher proficiency in either English or Japanese, including speaking, writing, and reading in a professional setting.
• At least conversational proficiency in the other language, sufficient to communicate effectively in day-to-day work.

 

Preferred Qualifications

Particularly Relevant Experience

Designing the Boundary Between OLTP and Analytics

• Experience defining the division of responsibilities between online transaction processing (OLTP) systems and analytical platforms such as Snowflake.
• Experience implementing architectures that include offloading aggregation workloads and reverse ETL to write data back from a data warehouse to operational databases.
• This experience is directly relevant to the database load reduction initiatives at the center of this role.

TypeScript / Node.js

• Ability to develop production-quality code in TypeScript and Node.js.
• Experience implementing and refactoring codebases that include large monorepos and shared libraries.
• This is particularly relevant because the application is built on a TypeScript / Node.js monorepo.

Operations, Reliability, and Governance

• Experience designing and operating service-level objectives (SLOs) and leading incident response.
• Experience implementing data classification, access controls, and retention policies as systematic processes.
• These capabilities directly support the governance foundation the team is building.

Technical Decision-Making and Stakeholder Alignment

• Experience leading technology selection and investment decisions involving multiple stakeholders.
• Ability to quantify trade-offs and gain agreement from stakeholders, including non-engineers.
• This is particularly important for changes requiring business cooperation, such as production data retention and deletion or migrations to new segment definitions.

Technical Leadership and Team Development

• Experience mentoring and developing engineers.
• Involvement in recruitment processes, including interview design, interviewing candidates, and improving the candidate experience.

PostgreSQL Fundamentals

• Basic knowledge of PostgreSQL, as Aurora PostgreSQL is used for selected services.

English Communication

• Ability to independently lead technical discussions and create technical documentation in English.
• The team operates in a multinational environment where Japanese and English are both used.

 

Additional Preferred Experience

Deep Knowledge of Distributed SQL Databases

• Experience with capacity planning, garbage collection (GC), region design, and performance limits in TiDB or similar distributed SQL databases.

Leading Data Warehouse Implementation

• Experience leading the implementation and adoption of Snowflake or a similar data warehouse, including cost management and defining the appropriate division of responsibilities between systems.

Operationalizing Data Governance

• Experience introducing data classification inventories, lineage, ADRs, and data contracts.
• Experience with data architecture and audit readiness in consideration of privacy regulations such as Japan’s Act on the Protection of Personal Information (APPI) and the GDPR.

Data Retention Policy Design and Negotiation

• Experience agreeing on data retention rules with business stakeholders, formalizing them into documented policies, and incorporating deletion into routine operations.

Rebuilding Test Strategies

• Experience leading team-wide efforts to improve test reliability, address the root causes of flaky tests, and rebuild test coverage.

Incremental Modernization of Large Systems

• Experience executing large-scale modernization initiatives, including monolith decomposition, shared library consolidation, and migration or retirement plans for legacy components.

Designing Vendor Collaboration Models

• Experience establishing and operating structured collaboration with database or data warehouse vendors, including regular technical reviews and escalation paths.

Cost Management

• A track record of analyzing infrastructure costs at the unit economics level and implementing cost reductions while communicating the implications to business stakeholders.

Community and Knowledge Sharing

• Contributions to open-source projects, technical writing, conference presentations, or other forms of technical knowledge sharing.

 

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.