Backend Development Engineer -CPaaS Business Department (RS Product Delivery & Innovation Div)
Rakuten · Tokyo, Japan · 1d ago
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)