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Starley

Product Engineer – Mid-Level

Salary
750万~
Location
Tokyo
Remote
On-site / hybrid
Visa
Sponsorship available
Language
Japanese: Conversational / English: Business Level
Posted
Mar 3, 2026
Python
Typescript
AWS
PostgreSQL
MySQL
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Overview

About the role

At Starley, we develop and operate "Cotomo," one of Japan's largest voice-based AI conversation applications. Under the concept "Whether you want to talk or remain silent," we are continuously exploring innovative ways to enhance human-AI interaction. This position requires not only backend expertise but also a strong commitment to overall product improvement including UX/UI enhancements and feature planning.

TechStack

Responsibilities

  • Design and implement efficient, highly available infrastructure to support high traffic
  • Build backend systems that integrate various AI models, including speech recognition, natural language processing, and speech synthesis
  • Develop streaming systems to deliver high-quality, real-time voice communication
  • Construct and optimize scalable frameworks for large-scale data processing
  • Collaborate with product managers and designers to participate in product improvement and feature planning
  • Who we're looking for:
  • An individual with a strong curiosity towards new technologies and a desire to grow through hands-on development
  • A problem-solver who prioritizes user experience and can devise practical solutions
  • A collaborative team player who values open communication

Required Skills

  • At least 3 years of experience in designing, implementing, and maintaining backend systems
  • Proficiency with relational databases (e.g., PostgreSQL, MySQL) and NoSQL databases
  • Basic understanding of real-time communication technologies (e.g., WebRTC, WebSocket)
  • Experience working with cloud platforms (e.g., AWS, GCP, Azure)
  • Experience in building or improving CI/CD pipelines (personal project experience is acceptable)
  • Practical experience in integrating new tools and technologies (e.g., RAG, Cursor, Devin) or equivalent hands-on experience
  • Fluency in Japanese for daily communication
  • Preferred Experience
  • While not specifically required, tell us if you have any of the following.
  • Experience working in an early-stage startup environment
  • Technical communication skills in English
  • Exposure to machine learning model operations
  • Experience with home server setup and management
  • Basic familiarity with deep learning models (e.g., LLMs) and fine-tuning techniques
  • Familiarity with speech recognition or natural language processing is a plus
  • Location/Work Style:
  • Based in Tokyo, Japan (primarily working from our Akasaka office with some remote flexibility)
  • VISA sponsorship available for international candidates
  • Compensation
  • Starting from 7,500,000 JPY per year, with performance-based stock options

About Starley

At Starley, we develop and operate "Cotomo," one of Japan's largest voice-based AI conversation applications. Under the concept "Whether you want to talk or remain silent," we are continuously exploring innovative ways to enhance human-AI interaction. This position requires not only backend expertise but also a strong commitment to overall product improvement including UX/UI enhancements and feature planning.

TechStack

Python, Rust, TypeScript, WebSocket, WebRTC, ElasticSearch, PostgreSQL, GCP, Azure, AWS, Unity, Weights & Biases, NVIDIA Triton, vllm, pytorch, transformers, deepspeed, Dataform, BigQuery, Sentry, Slack, Github

Quick Facts

CompanyStarley
LocationTokyo
Salary750万~
RemoteOn-site / hybrid
VisaAvailable
LanguageJapanese: Conversational / English: Business Level
Interested in this role?

Submit your application for this role at Starley.

Apply Now