Senior Software Engineer, Platform API - Ruby on Rails

Responsibilities

- Design, ship, and operate Ruby on Rails Platform APIs end-to-end—from spec to rollout—meeting agreed availability/latency SLOs.

- Drive API design (OpenAPI/contract tests), versioning/deprecation, and compatibility for first-party UIs and partner integrations.

- Operate across the stack as needed, from backend APIs to front-end experiences, based on product needs.

- Ensure scalability, performance, and operationalization remain primary concerns throughout development.

- Keep up to date on novel technical concepts that we should adopt (and which ones we should ignore).

- Evaluate and introduce pragmatic improvements (framework/library upgrades, testing strategy, CI/CD/IaC) with clear trade-offs—in writing.

Requirements

- 5+ years of software engineering experience with a proven track record.

- Have the ability to work full-stack (from the DB all the way to the Frontend).

- Writing Web APIs in Ruby on Rails.

- SQL and working with and maintaining Relational Databases in a production environment.

- System architecture and design

- Knowledge of design patterns involving APIs that communicate with many backend components.

- Variety of testing approaches, correctness through design, and a holistic approach to quality.

- Cloud technologies (particularly AWS) and development/deployment in a cloud infrastructure.

- Write clear design docs and incident postmortems; communicate across time zones.

- Comfortable working in English and Japanese: can participate in team meetings, ask/answer questions, and write simple tickets/Slack messages in either language.

Nice to haves

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

- Sense of project ownership and responsibility.

- Experience owning and leading short to medium-term technical direction across teams

- Business-level English proficiency and conversational-level Japanese proficiency

- Experience working in a different programming environment, such as the JVM (Java or Kotlin) or a different API style, such as JSON: API.

- Contributed to a production-grade web application handling high traffic.

- Experience in developing a fully managed cloud service.

- Experience with microservices-oriented architectures and authentication/authorization challenges.

- Made open source contributions.