This position is closed and is no longer accepting applications.

Senior Ruby on Rails Developer

HeartCore Shinagawa-ku, Tokyo
    💴 ¥6M ~ ¥12M annually
    🏡 Partially remote
    🧪 3+ years experience required
    💬 No Japanese required
    🌏 Japan residents only
    🧳 No relocation support

About HeartCore

HeartCore Shinagawa-ku, Tokyo

HeartCore has the number one CMS used in Japan. We’re currently expanding globally and in 2022 we had our IPO on the New York Stock exchange.

Key benefits

  • Horizontal communication
  • Little to no overtime

About the position

You will work alongside a Senior Rust Developer to lead the implementation of a SaaS platform in Rust. No prior experience with Rust is necessary, only the motivation to learn it.


  • Learn Rust. You’ll spend up to your first three months learning the language and becoming productive with it.
  • Be directly involved in overseeing the main platform development and lead its implementation.
  • Work across the full product tech life cycle from discovery to delivery. Build internal and external tools to support HeartCore global expansion. Build a web platform and integrate with external APIs.
  • Innovate with Rust breaking boundaries.
  • You work very closely with the CTO and Designers, often interact with our internal sales teams and closely with our board members.
  • Conduct code reviews in coordination with other team members and help maintain a high standard of quality across the codebase.
  • Lead, mentor, and learn from other engineers on our growing team.
  • Take features from concept to fully-fledged product.


  • Resident of Japan with valid permission to work
  • Motivated and eager to learn Rust.
  • Ruby on Rails expertise (3+ years). This is a hard requirement.
  • Available to start working before the end of August 2023 (the sooner the better)
  • Deep experience in building complex modern web applications. We’d expect a developer to typically take 5 years to pick up this level of experience.
  • Experience working with SQL databases.
  • An understanding of the full web technology stack (e.g. HTTP, cookies, asset loading, caching, REST, etc).
  • Good knowledge of security best practices.

Nice to haves

While not required, tell us if you have any of the following.

  • Knowledge of Rust, Elixir or Python
  • Familiarity with functional or component testing of services
  • Experience building REST and Websocket API clients
  • Basic understanding of how to sign an encrypted request
  • Entrepreneurial spirit


6 to 12 million JPY annually.

Hiring Process

  1. 1

    Application screening

  2. 2

    Initial interview

    The goal of this interview is to understand your needs and expectations, and present the company and the role.

  3. 3

    Technical interview

    This will focus on understanding your technical skill level, and may include a technical challenge. If something is unclear, we may schedule a final followup interview.

  4. 4


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