Database Reliability Engineer

Job Overview

Database Reliability Engineer (DBRE) - Mercari
Employment Status: Full-time
Work Hours: Full Flextime (no core time)
Office: Roppongi

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.

Key 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).

Required Qualifications

• 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)