Database Reliability Engineer (DBRE) - Mercari

Employment Status: Full-time
Work Hours: Full Flextime (no core time)
Office: Roppongi

For more details, see the Overview of Our Positions section on our Careers site.

　
About Mercari

Circulate all forms of value to unleash the potential in all people

"What can I do to help society thrive with the finite resources we have?" The Mercari marketplace app was born in 2013 out of this thought by our founder Shintaro Yamada as he traveled the world. We believe that by circulating all forms of value, not just physical things and money, we can create opportunities for anyone to realize their dreams and contribute to society and the people around them. Mercari aims to use technology to connect people all over the world and create a world where anyone can unleash their potential. For more information about Mercari Group's mission, see Mercari's Culture Doc.

　
Organization/Team Mission

Mercari Engineering Principles

Mercari Engineering Principles are a shared understanding that serves as the foundation of engineering beliefs and behavior at Mercari. The Engineering Principles are designed to complement the organizational identity (Mercari's mission, values, and culture) from an engineering viewpoint. These principles ultimately help us achieve Mercari's mission by defining the ideal state we seek to realize in the long term.

Passion For The Product
Grow Together
Solve Through Mechanisms
Collaborate Openly

For more details, please see the following link:

Engineering Culture

In the DBRE Team, we own the reliability, scalability, and cost efficiency of Mercari's production databases. Our core platform today is TiDB Cloud, serving items, transactions, and user data at hundreds of thousands of QPS under a 99.99% availability SLA. Over the next 12–18 months, we are expanding our scope to a multi-engine DBRE — adding AlloyDB, CloudSQL (PostgreSQL/MySQL), and eventually Spanner — while driving cost optimization, automation, and tighter integration with product and platform teams.

See here for more information about our mission and values.

　
Work Responsibilities

Operate production databases (TiDB, MySQL, PostgreSQL, and managed cloud DBs) under a 99.99% availability SLA, including on-support rotation for urgent issues.
Lead end-to-end epics independently — from design through rollout, monitoring, and post-launch tuning.
Design and execute database migrations (engine changes, version upgrades, on-prem to cloud cut-overs) with zero or minimal downtime.
Build and operate CDC and streaming pipelines (Debezium, TiCDC, Kafka) feeding analytics and downstream services.
Write Infrastructure-as-Code (Terraform, Ansible) and automation in Go or Python to reduce toil and scale operations.
Build and maintain database monitoring, alerting, and SLO/SLI dashboards (Datadog, Grafana).
Diagnose and resolve production incidents, lead post-mortems, and drive permanent fixes.
Perform performance tuning on production workloads (query plans, schema, indexing, replication topology).
Partner with product and platform teams on schema changes, capacity planning, and new database adoption.
Contribute to the team's expansion into multi-engine DBRE by learning and productionizing new database engines (AlloyDB, Spanner, and others).

　
Unique Challenges

Operating TiDB at Mercari scale (hundreds of thousands of QPS, multi-TB datasets) with a 99.99% SLA.
Expanding the team's operational scope from a TiDB-centric model to a multi-engine portfolio (AlloyDB, CloudSQL, Spanner) — you will help define the operational model as we go.
Balancing ~40–50% reactive work (alerts, on-support tickets, DDL operations, incident response) with project delivery.
Driving cost optimization on a growing database bill without compromising reliability.
Working in a bilingual environment: daily team syncs are primarily in Japanese; cross-team collaboration is in English.

　
Qualifications

Required Experience/Skills

Production DBA or DBRE experience with MySQL, TiDB, PostgreSQL, or an equivalent RDBMS, including an understanding of internals (replication, indexing, query planning).
Experience operating databases at scale (>10K QPS or >1TB datasets) under production SLAs.
Production experience with GCP or AWS managed database services (CloudSQL, AlloyDB, RDS, Aurora, or equivalent).
Infrastructure-as-Code experience (Terraform, Ansible) and scripting in Go, Python, or shell.
Hands-on experience with database monitoring and observability (Datadog, Grafana, or equivalent).
Experience owning incident response, performance tuning, and on-call or on-support rotations.
Ability to lead epics end-to-end without teammate support.
Willingness to learn new database engines (AlloyDB, Spanner, PostgreSQL) beyond your core expertise.

Preferred Experience/Skills

Experience with distributed database internals (sharding, replication, consensus) or operating TiDB, Spanner, Vitess, or CockroachDB in production.
CDC / streaming pipeline experience (Debezium, TiCDC, Kafka Connect, or similar).
Kubernetes operational experience.
Experience leading major database migrations (engine, version, or data center).
Experience driving cross-team coordination for schema changes, migrations, or platform adoption.

Language

Japanese: Independent (CEFR – B1)
English: Independent (CEFR – B1)

For details about CEFR, see here.

Learn More About Mercari Group

Careers site: https://careers.mercari.com/en/
Mercan: https://mercan.mercari.com/en/
Social media: X / LinkedIn

　
Recruiting at Mercari

At Mercari Group, we value empathizing with and embodying the mission and values of the Group and each company. To promote the creation of an organization that maximizes the total amount of value exhibited by all members, we would like to understand the experience and skills of each candidate as accurately as possible.

Recruiting cycle at Mercari Group

Application screening
Skill assessment: For engineering positions, you will be asked to complete a skill assessment on HackerRank or GitHub. For non-engineering positions, you may be asked to complete an assessment depending on the position. (The timing of the assessment may coincide with the interview process.)
Interview: The number of interviews may vary depending on the position.
Reference check: We will ask for online references around the timing of the final interview.
Offer: Offers will be determined carefully in consideration of the final interview and the reference check.

Learn more about our recruiting process here.

　
Equal Opportunity Hiring

Here at Mercari, we work to realize a world in which no one's potential is limited by their background and everyone has the opportunity to freely create value. We also firmly believe that a mindset of Inclusion & Diversity is essential for us to achieve our mission.

This, of course, extends to our hiring practices as well. Mercari is committed to eliminating discrimination based on age, gender, sexual orientation, race, religion, physical disability, and other such factors so that anyone who shares our mission and values can join us, regardless of their background. For more details, please read our I&D statement.

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