We are looking for a Senior Software Developer with strong experience in Ruby on Rails and React to join a product-focused engineering team and help build, evolve, and maintain high-quality web applications.

This is a full-time, fully remote position within Spain. You will work across both backend and frontend, taking ownership of features from technical design through implementation, testing, deployment, and ongoing improvement.

What You'll Do

- Design, build, and maintain scalable web applications using Ruby on Rails and React.

- Develop and evolve backend services, APIs, business logic, and data models.

- Build responsive and maintainable frontend experiences with React.

- Take ownership of features throughout the full software development lifecycle.

- Participate in technical design and architecture decisions.

- Write clean, maintainable, well-tested code.

- Review code and contribute to engineering standards and best practices.

- Diagnose and resolve complex bugs and production issues.

- Improve application performance, reliability, security, and maintainability.

- Collaborate closely with other engineers and cross-functional stakeholders.

- Identify technical debt and propose pragmatic improvements.

- Contribute to a culture of technical excellence, ownership, and continuous improvement.

What We're Looking For

- 5+ years of professional software development experience.

- Strong professional experience with Ruby and Ruby on Rails.

- Strong professional experience building modern frontend applications with React.

- Experience developing and consuming REST APIs or similar web APIs.

- Solid understanding of relational databases and data modelling.

- Experience working with automated testing and maintaining reliable production systems.

- Strong knowledge of Git and modern software development workflows.





- Ability to understand existing codebases and improve them incrementally.

- Strong debugging and problem-solving skills.

- Ability to make sound technical decisions independently.

- Experience taking ownership of features and delivering them end-to-end.

- Comfortable working in a remote and collaborative engineering environment.

Senior-level expectations

This is not only an implementation role.

We are looking for someone who can:

- Understand the broader technical impact of their decisions.

- Break down complex problems into pragmatic solutions.

- Balance product delivery with long-term maintainability.

- Identify risks before they become production problems.

- Challenge technical decisions constructively when necessary.

- Help improve code quality and engineering practices across the team.

- Support and mentor other developers when appropriate.

- Communicate technical decisions clearly with both technical and non-technical stakeholders.

Nice to have

Experience with some of the following would be valuable, but is not required:

- TypeScript

- PostgreSQL

- Redis

- Background job processing

- Docker

- AWS or other cloud platforms

- CI/CD pipelines

- Performance optimisation

- Observability and production monitoring

- SaaS or product-driven development environments

Working model

- Full-time

- Fully remote within Spain

- Candidates can be based anywhere in Spain.

Compensation

€45,000–€70,000 gross per year, depending on experience, technical depth, and overall fit for the role.

What We're Looking For Beyond The Stack

Technology matters, but we are primarily looking for an engineer who combines strong technical foundations with ownership, good judgement, and the ability to build software that works reliably in production.

You should be comfortable working autonomously, collaborating with others, navigating ambiguity, and continuously improving both the product and the codebase.

📌 Senior Software Developer – Ruby on Rails + React (Madrid)
🏢 Cribbers
📍 Madrid