Senior/Staff Software Engineer - Backend

About the role Starley is developing and operating "Cotomo", one of Japan's largest voice-based AI conversation applications. We are redefining the relationship between humans and AI. You will be responsible for designing, implementing, and operating the core backend systems for Cotomo and our upcoming new products. Responsibilities Design and implement efficient, highly available infrastructure to support high traffic Build and maintain robust backend systems integrating advanced AI models, including speech recognition, natural language processing, and speech synthesis Develop high-quality, real-time streaming systems and scalable data processing frameworks Collaborate with product managers, designers, and marketing teams to define and execute the overall product vision and strategic improvements. Tech Stack Python, Rust, TypeScript, WebSocket, WebRTC, ElasticSearch, PostgreSQL, GCP, Azure, AWS, Unity, Weights & Biases, NVIDIA Triton, vllm, pytorch, transformers, deepspeed, Dataform, BigQuery, Sentry, Slack, Github Requirements 6+ years of experience in designing, implementing, and operating backend systems Experience in launching new software products in a leadership role Proficiency with relational databases (PostgreSQL/MySQL etc.) and NoSQL databases Experience in developing systems that handle large-scale traffic Basic knowledge of real-time communication technologies such as WebRTC and WebSocket Experience in operating systems on cloud platforms (AWS, GCP, Azure, etc.) Experience in developing applications using RAG - personal projects are acceptable Fluency in Japanese for daily communication Desired Experience While not specifically required, tell us if you have any of the following. Enthusiasm for learning and applying new technologies to product development Ability to think from a user experience perspective and creatively solve technical challenges Values teamwork and can communicate openly Experience working in early-stage startups (within a few years of founding) Experience in operating machine learning models in production environments Experience in building and maintaining home server environments Experience in training and fine-tuning deep learning models such as LLMs Knowledge or experience in speech recognition and natural language processing Location/Work Style Based in Tokyo, Japan Some remote work possible, but regular office presence required VISA sponsorship available for international candidates Compensation 8,500,000 JPY and above, with performance-based stock options