Backend Engineer

  • Tokyo
  • Partial Remote
  • Full-time
  • May 13, 2024
Apply from Japan Only
No relocation to Japan
(No visa sponsorship from overseas)
Language Requirements
Japanese: Business Level
English: Business Level
Minimum Experience
Senior or above

Business Description

With the mission of "Make the next mainstream", we develop and operate Zapshot, a voice-based social networking service that everyone in Generation Z wants to use. Zapshot is a new social networking application focused on voice messaging and dual video creation for Generation Z in the US market.

Voice Messaging - Chatting with friends is automatically converted to text and sent in both voice and text.

Dual Video Creation - Record out-camera and in-camera simultaneously without being restricted to any model and share with the worldwide Zapshot community. Chat Explore feature allows users to connect with friends with similar interests and enjoy voice chat while managing various communities.

The product was released in December 2022 and incorporates new AI and web3 technologies and is poised to be a rapidly growing product from the US.

Job Duties

  • SNS application development
  • API development for various functions of the service
  • Developing API for various functions of the service
  • Development of management screens and KPI screens required for operation
  • Planning and implementation to ensure stable operation when the number of users and content postings increase. 
  • Planning and implementation to ensure stable operation when the number of users and content submissions increase.


Must have requirements

  • At least 3 years of experience in development and operation of apps and services.
  • Experience designing and developing REST API servers with TypeScript (express)
  • The candidate must have the ability to work with stakeholders and be self-driven to ensure the success of the product.
  • Development skills that take performance and scalability into consideration 
  • Business level Japanese (N2). People with no certifications but have the confidence to be able to communicate well in Japanese are also welcome to apply


Nice to have 

  • Experience in performance tuning of RDBMS/NoSQL (especially MySQL)
  • Experience in development and operation of microservice architecture
  • Experience in designing SNS functions (chat, timeline, etc.)
  • Knowledge and experience in networking, Linux, monitoring systems, and logging
  • Experience developing in a cloud environment (especially AWS)
  • Experience in development with English-centered communication


Profiles that would fit into this role

  • Those who value a problem-solving attitude and have the will to see things through to the end.
  • People who are cooperative, eager to learn, and can contribute to the growth of the entire team.
  • People who are full of curiosity as engineers and want to challenge new technologies and knowledge.
  • People who respect diversity and want to work passionately with colleagues from various backgrounds




私たちは "Make the next mainstream"というミッションのもと、Z世代で誰も使いたくなる音声ベースSNS「Zapshot」を開発、運営しています。
ボイスメッセージング - 友達とチャットすると、自動的にテキストに変換され、音声とテキストの両方で送信されます。
デュアルビデオ作成 - 機種に制限されずにアウトカメラとインカメラを同時に録画して、世界中のZapshotコミュニティと共有することができます。


  • SNSアプリ開発
  • サービスの各種機能に合わせたAPI開発
  • 運用に必要な管理画面やKPI画面の開発 ・ユーザー数やコンテンツ投稿数が増加した時にに安定して稼働するための計画と実装




  • 3年以上のアプリ・サービスの開発・運用経験
  • TypeScript (express) でREST APIサーバーの設計・開発経験
  • ステークホルダーと連携しプロダクト成功に向けて自走できる行動
  • パフォーマンスとスケーラビリティを考慮した開発スキル
  • 日本語ビジネスレベル


  • RDBMS/NoSQLのパフォーマンス・チューニング経験(特にMySQL)
  • マイクロサービスアーキテクチャでの開発・運用経験
  • SNS機能(チャットやタイムラインなど)の設計知識や経験
  • ネットワーク、Linux、監視システム、ロギングの知識・経験
  • クラウド環境での開発経験(特にAWS)
  • 英語中心のコミュニケーションでの開発経験

◆ こんな方におすすめ

  • 問題解決に取り組む姿勢を大切にし、最後までやり抜く意志を持っている方
  • 協調性があり、学ぶ姿勢が旺盛で、チーム全体の成長に貢献できる方
  • エンジニアとしての好奇心旺盛で、新しい技術や知識にどんどん挑戦したい方
  • 多様性を尊重し、様々なバックグラウンドを持つ仲間たちと情熱的に働きたい方


Reazon Holdings' vision is to be the best company in the world. To do that, they're developing four main businesses: Ad tech, Social gaming, Media and Food tech.

By leveraging synergies among their businesses, Reazon Holdings continues to create new, unique businesses that other companies can't replicate.



View Reazon Holdings's company page

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