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Software Engineer, Search - US App

Salary not provided

PrometheusKafkaSolrGrafanaJavaGoAzureDockerPythonElasticSearchPHPGCPAWSKubernetes
English: Fluent
english_only

Minimum year of experience: 5

Mercari

Software Engineer, Search - US App

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

Organization/Team Mission

The team's mission is to help buyers discover the most relevant items and empower sellers by improving their visibility in the marketplace. We strive to provide a fast, trustworthy, and effective search experience that seamlessly connects millions of users with what they’re looking for, at scale.

The Search team is responsible for the end-to-end development and operation of the search system, including relevance tuning, query understanding, and infrastructure reliability. Built on Elasticsearch, the system handles high query volumes and constantly evolving inventory with stability, freshness, and cost efficiency.

Recent or ongoing initiatives include:

  • Modernizing ranking and retrieval pipelines to improve conversion, engagement, and search precision.
  • Strengthening platform stability and flexibility through real-time indexing, cache optimization, search traffic resilience, and observability tooling.
  • Collaborating with product, backend, and infrastructure teams to build a world-class search experience.

Work Responsibilities

  • Own the end-to-end search delivery cycle: independently identify improvement opportunities through log, user signal and metric analysis; define and track KPIs; and ship iterations that improve relevance and conversion while aligning with product and business goals.
  • Design, develop, and maintain search infrastructure and backend microservices.
  • Build and optimize search indices, ranking algorithms, and query pipelines focused on relevance, retrieval efficiency, and low latency.
  • Design and implement gRPC and RESTful endpoints for inter-service and client communication.
  • Enhance system scalability, performance, and reliability by designing reusable components and shared libraries, optimizing caching, databases, and load balancing, and enforcing comprehensive automated tests with robust monitoring and observability.
  • Mentor junior engineers, lead code reviews, and actively contribute to architectural decisions and technical documentation.
  • Collaborate with cross-functional teams including product, infrastructure, and QA to deliver high-impact features and improvements.

Unique Challenges

  • Own the continuous improvement cycle for search, analyzing metrics, proposing experiments, and delivering enhancements that provide highly relevant, fast, and reliable search experiences to meet diverse customer needs.
  • Collaborate closely with product managers, backend engineers, and machine learning specialists to design advanced, end-to-end systems.
  • Architect and implement highly scalable services to support user and product growth.
  • Contribute proactively to engineering culture by sharing ideas, driving improvements, and mentoring peers.
  • Develop a deep understanding of the US market to ensure product decisions align with customer expectations and business goals.
  • Work in a globally distributed team, collaborating across time zones and cultures.

Qualifications

Required Experience/Skills

  • Strong hands-on experience with search technologies such as Elasticsearch, OpenSearch, or Solr, including schema design, relevance tuning, and query optimization.
  • Ability to independently analyze search metrics and ship measurable improvements in production systems.
  • Bachelor’s degree in Computer Science, Software Engineering, or a related field (or equivalent practical experience).
  • 5+ years of professional experience developing and operating search engines and/or backend services in high-traffic production environments.
  • Experience building and operating microservices at scale, including containerization (Docker, Kubernetes), CI/CD and Infrastructure as Code (Terraform), observability (Prometheus, Grafana), and optimization of databases, caching, concurrency, and search relevance/latency.
  • Strong programming expertise in Java or Go; familiarity with Python or PHP is a plus.
  • Excellent English communication skills, with the ability to collaborate effectively across functions and regions.
  • Demonstrated ability to mentor and guide junior engineers.

Preferred Experience/Skills

  • Experience with vector search or semantic search frameworks.
  • Domain knowledge of marketplace or e‑commerce platforms.
  • Experience deploying and scaling services on major cloud platforms such as Google Cloud Platform (GCP), AWS, or Azure.
  • Familiarity with message queues and event-driven architectures (e.g., Pub/Sub, Kafka).
  • Contributions to open-source projects, especially in search or backend domains; or public technical engagement through blogs, talks, or conferences.
  • Experience working within large, cross-functional and geographically distributed teams.

Language Requirements

  • English: Business level (CEFR B2 or higher) required
  • Japanese: Basic (CEFR - A2) optional

More about CEFR

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Recruiting Process

  1. Application screening
  2. Skill assessment (HackerRank/GitHub for engineering roles)
  3. Interview(s)
  4. Reference check
  5. Offer

Read more about our recruiting process

Equal Opportunity Hiring

We are committed to eliminating discrimination based on age, gender, sexual orientation, race, religion, physical disability, and other factors. We encourage anyone who shares our mission and values to apply.
Read our Inclusion & Diversity statement.

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