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Open nowPosted 19 days ago

Backend Development Engineer -CPaaS Business Department (RS Product Delivery & Innovation Div)

rakuten107 open roles

Where
Tokyo, Japan
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Your applicationOpen nowBackend Development Engineer -CPaaS Business Department (RS Product Delivery & Innovation Div)rakuten · Tokyo, Japan

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The clock on this job

Early applications get read.

12.3% of postings close within 7 days. Measured by our own scanner across the market. rakuten postings stay open a median of 12 days.

Share of postings closed within
  1. 2.1%1 day
  2. 4.5%3 days
  3. 12.3%7 days
  4. 19.3%14 days
  5. 35.6%30 days
  6. 58.1%60 days
This job: posted 19 days ago

rakuten median: 12 days open

The posting

Job Description:

About Organization

We are building the next generation of our CPaaS platform, a robust ecosystem powering multi-channel communication services. Our platform supports global traffic across SMS, Email, Voice, WhatsApp, LINE, RCS, Passkey, and advanced Authentication services. We are looking for a highly skilled Backend Engineer to drive the scalability, reliability, and evolution of these services within a high-autonomy, fast-paced R&D environment.

Job Duties

  • Backend Service Development: Design, implement, and optimize microservices powering multi-channel communication workloads.
  • Feature Engineering: Build and enhance backend capabilities supporting messaging, identity, verification, and communication APIs.
  • Distributed Systems Engineering: Develop high-throughput, low-latency services for global CPaaS traffic.
  • Database Engineering: Design schemas, optimize queries, and ensure peak performance across databases.
  • Cloud-Native Architecture: Deploy and operate services on Kubernetes, ensuring resilience, scalability, and cost-efficiency.
  • API-First Engineering: Build clean, scalable REST APIs and contribute to API-first product architecture.
  • CI/CD & GitOps: Manage version-controlled pipelines for build validation, automated testing, and safe deployments.
  • AI-Enhanced Development: Utilize LLM-based tools (e.g., Claude, Codex) to improve code quality, automate documentation, and accelerate development workflows.
  • Observability: Ensure system visibility using Grafana, Prometheus, and structured logging.
  • Cross-Functional Collaboration: Partner with Product Managers, QA, DevOps/SRE, and UI/UX teams to deliver high-quality features.
  • Engineering Excellence: Uphold coding standards, conduct code reviews, and drive continuous improvement of engineering practices.

Minimum Qualifications

  • 5+ years of hands-on backend development experience.
  • Strong proficiency in Java or Golang.
  • Expertise with Postgres and MySQL.
  • Hands-on experience with Kubernetes and containerization.
  • Experience with CI/CD pipelines (GitHub Actions preferred).
  • Experience with Microservices and API-first system design.
  • AI-Assisted Development: Proficient in leveraging LLM-based tools for coding, automation, and workflow acceleration.
  • Advanced English proficiency (strong communication, documentation, and collaboration skills).

Preferred Qualifications

  • Domain experience with communication protocols (SMPP, SIP, REST APIs, WebRTC).
  • Experience across multiple CPaaS domains (SMS, Email, Voice, Passkey, Auth Services, WhatsApp, LINE, RCS, etc.).
  • Proven ability to work effectively in fast-moving, high-autonomy environments.

Key Interfaces

  • Backend Engineering Team
  • QA & Automation Teams
  • DevOps / SRE
  • Product Managers
  • UI/UX Designers
  • Project Managers
  • R&D Leadership / CTO

Languages:

English (Overall - 3 - Advanced)

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