Senior Search Platform Infrastructure Engineer

Senior Search Platform Infrastructure Engineer

Mercari, inc. · Minato, Japan (Hybrid) · Full-time · Posted 2026-06-05

Workplace: hybrid

Department: Engineering

Description

本ポジションは日本語JDの用意がありません。

Senior Search Platform Infrastructure Engineer

• 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

The Autonomous Cloud group in the Platform Division builds and operates the foundational infrastructure that lets every engineering team at Mercari ship products safely and quickly - covering the Kubernetes platform, search infrastructure, observability, networking, and FinOps. Our charter is to make complex infrastructure simple to consume, so product teams can spend their time on customer value rather than on running systems.

The Search Infrastructure team - part of the Autonomous Cloud division - runs Mercari's search platform as a managed service for engineering teams across the company. We operate large-scale, product-critical Elasticsearch clusters and supporting systems (Redis, vector databases) that power product search across Mercari's marketplace. Our job is to abstract away the operational complexity of search so product teams can focus on building features. We are a small, deep team that combines hands-on operation of search clusters with in-house expertise on search-engine technology - partnering closely with internal Search and product teams.

See here for more information about our mission and values.

Work Responsibilities

• Co-own the Elasticsearch cluster lifecycle: provisioning, sizing, upgrades, shard / replica strategy, and index management for product-critical search workloads. 
• Join the search infrastructure on-call rotation after ramp-up; lead incident response, root-cause analysis, and follow-through improvements. 
• Drive performance and reliability initiatives across the cluster, JVM, and query layers. Improve the search APIs and aggregation services consumed by product teams. 
• As bandwidth allows, collaborate with the Platform Infrastructure team on high-impact Kubernetes and Terraform changes as a senior reviewer and engineer; mentor engineers across both teams.

Unique Challenges

• Operating a search platform that serves product-critical workloads at very large scale (hundreds of millions of indexed items at sustained high query volume) with demanding availability and latency expectations. 
• Owning the full search infrastructure stack end-to-end - from cluster operations and JVM tuning down to query-path performance - across a small, deep team where each engineer has real platform-level ownership. 
• Balancing day-to-day reliability of running clusters with longer-horizon investments: version upgrades, automation, and evaluating next-generation search and vector technologies. 
• Sitting at the boundary between infrastructure and product - translating between platform-level concerns (capacity, reliability, cost) and product-team needs (indexing patterns, query behavior, search experience).

Qualifications

• Required Experience/Skills

• Shared belief in Mercari's mission and values. 

• Senior-level engineering experience operating distributed systems in production at scale. 
• Strong system-design and distributed-systems fundamentals: consistency, replication, capacity planning, failure modes. 
• Production ownership of Elasticsearch (or a comparable Lucene-based search engine) - cluster sizing, JVM / heap tuning, query-performance debugging, shard strategy. 

• Track record of owning a technical domain end-to-end: design, build, on-call, incident follow-through, long-term roadmap. Proficiency in Go and/or Java.

• Preferred Experience/Skills

• Lucene internals or JVM performance-engineering depth. 

• Vector search knowledge. 
• Production experience operating Kubernetes (GKE, EKS, or AKS) - cluster upgrades, incident debugging. 
• Terraform at scale (custom modules, large-blast-radius migrations). 
• CI/CD platform experience (GitHub Actions, Jenkins, or similar). 

• Search / data services for C2C or e-commerce at scale.

• Language 

• Japanese: Not required

• English: Business level (CEFR – B2)

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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