【Mobile Engineer】Hyper-Growth Live Streaming | Full Remote | JLPT N2+

★Mobile Engineer（Android/IOS/Flutter）| Music Live Streaming App

• Business Level Japanese Required

◆ Fully Remote Work

◆ Start-up Company

◆ 120 days of annual leave

◆ Annual salary: 8 million yen - 15 million yen

-------------【About the company】-------------

A music live-streaming platform company that develops and operates a song-specific live-streaming app. Featuring a vast music distribution environment utilizing JOYSOUND sound sources and a system where rewards can be earned for each performance, the platform provides a music community where singers and listeners connect. It aims to build an ecosystem that expands the entertainment experience centered on singing and maximizes the power of song.

■Business Overview

The company released its song-specific live-streaming app in July 2023. It aims to revolutionize the music domain—where previously only a limited few could succeed—by building an ecosystem where a broader range of singers and peripheral creators can be recognized and earn income. Through this transformation, the company seeks to create a world where people can enjoy music more closely and freely.

With investment and business support from XING Inc. (provider of "JOYSOUND") and DeNA Co., Ltd. (operator of "Pococha," one of Japan's largest live-streaming apps), the company's sales are growing at more than double annually, reaching a scale of 360 million yen in monthly sales.

The organization is built around a small, elite team primarily composed of members with backgrounds in the live-streaming industry. In 2026, backed by solid product quality and a stable business foundation, the company is aiming for even further growth.

-------------【 Job Description】-------------

■Business Overview

The company released its song-specific live-streaming app in July 2023. It aims to revolutionize the music domain—where previously only a limited few could succeed—by building an ecosystem where a broader range of singers and peripheral creators can be recognized and earn income. Through this transformation, the company seeks to create a world where people can enjoy music more closely and freely.

With investment and business support from XING Inc. (provider of "JOYSOUND") and DeNA Co., Ltd. (operator of "Pococha," one of Japan's largest live-streaming apps), the company's sales are growing at more than double annually, reaching a scale of 360 million yen in monthly sales.

The organization has been managed by a lean, elite team primarily composed of members from the live streaming industry (3 executives + external contractors). Starting in 2025, backed by stable product quality and business foundations, the company will enter a "growth phase" aiming for further expansion. In this phase, the company is seeking talented engineers to lead the product development.

■Responsibilities

You will be responsible for development aimed at improving the user experience (UX) and quality of Live Streaming App C through video and audio streaming technologies.

・Minimize live streaming latency as much as possible

・Deliver high-quality video and audio

・Redesign and refactor existing streaming and viewing features to make them easier to maintain and develop further

You will also be involved in developing the viewer player (including karaoke and gift features) to ensure smooth streaming and viewing.

■ Development Environment

・Delivery: Tencent Real-Time Communication

・Infrastructure: GCP (GKE, Cloud Run, GCS, Pub/Sub), Terraform

・DB: Google Cloud Spanner

・Server: Go

・App: Flutter/Dart

・Web Frontend: TypeScript, Next.js, React

・Other: GitHub, Figma, Notion, Slack

■ About the Team

The engineering team currently consists of 10 members, most of whom are external contractors or side-business participants. Development is conducted fully remotely, with nearly all communication taking place on Slack and GitHub.

The team includes PdMs and server engineers, with whom you will collaborate on development. Additionally, separate QA and CS teams are in place, and you will work in coordination with them to perform your duties.

-------------【 Requirements】-------------

【Required】

・Experience developing using video streaming platforms (such as AWS IVS, Tencent TRTC, Wowza Media Server, Agora, etc.)

・Practical experience developing iOS or Android apps

・Ability to quickly learn API development using Flutter/Dart

・Experience collaborating on development projects using GitHub

【Preferred】

・Experience developing a video library

・Experience with personal (non-commercial) development is also acceptable

・Experience developing filters for camera apps

・Experience developing face-swapping apps

・Experience developing video players using H.264, VP9, or similar formats

【Ideal Applicants】

・Willing to commit to growing a service in the 0-to-1 stage

・Seeking to work on services that focus on enhancing the user experience

・Motivated to proactively tackle any challenges to ensure the service’s success

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■Welfare

• Full social insurance coverage

• Two-day weekend (Saturday and Sunday) and national holidays

• 120 days of annual leave

• Fully remote work

• Stock options provided

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