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Senior Full-Stack Engineer (BE)

3СommasTallinn, Estonia | Barcelona, Spain | WorldwideOnsite

3Commas is a leading platform for crypto trading automation. We’re building a modular SaaS product that empowers traders worldwide to scale strategies, automate workflows, and connect seamlessly with top exchange APIs.
We’re looking for a Full-Stack Engineer (Backend-Focused) with strong Ruby on Rails experience and a passion for building secure, high-performing systems. You'll play a key role in shaping our core architecture, integrating external services, and mentoring fellow engineers — all while ensuring product quality from day one.

Responsibilities:


  • Develop and maintain a modular, scalable SaaS platform using Ruby on Rails.
  • Implement new features and improve existing ones in close collaboration with product and design teams.
  • Take ownership of your code in production: monitoring, alerting, and ongoing support.
  • Address high-load and security-related challenges in backend and full-stack solutions.
  • Mentor and support the growth of other engineers on the team.
  • Integrate external API services and ensure their secure and stable operation.
  • Ensure code quality and performance through early involvement in QA and testing workflows (shift-left approach).
  • Contribute to quality through automated tests, code reviews, and proactive refactoring.
  • Collaborate closely with cross-functional teams including DevOps and QA.
  • Stay up to date with best practices in backend architecture, performance, and security.

Requirements:


  • 4+ years of experience in Ruby on Rails backend development.
  • 6+ years of proven full-stack commercial development experience.
  • Strong understanding of PostgreSQL and relational data modeling.
  • Familiarity with AWS serverless services (e.g., Lambda, DynamoDB).
  • Hands-on experience with key-value stores (Redis, Memcached, etc.).
  • Experience integrating third-party APIs and services.
  • Adherence to modern software development practices: TDD, CI/CD, clean code, refactoring.
  • Ability to design and build scalable, secure, and maintainable features.
  • Strong communication skills and collaborative mindset.
  • Proficiency in English (B2 level or higher, spoken & written).
  • Commitment to participating in quality assurance workflows and a strong understanding of the “shift-left” approach.

Nice to Have:


  • Basic experience with Go and interest in growing your skills in it.
  • Familiarity with Kubernetes and microservice orchestration.
  • Knowledge of Kafka, RabbitMQ or similar messaging/streaming systems.
  • Experience tackling high-load scenarios and optimizing performance bottlenecks.
  • Hands-on experience with observability tools like Grafana, CloudWatch, etc.

What We Offer:


Product & Architecture Ownership


Work on a product that values quality, performance, and long-term impact. Your decisions shape our platform.

Modern Tech Stack


Ruby on Rails, AWS Lambda, DynamoDB, Redis, PostgreSQL — plus opportunities to use Go where it makes sense.

Remote-First Culture


Collaborate across borders with a globally distributed team. Async-first workflows with office access in Barcelona and Tallinn.

High Engineering Standards


We care about clean code, thoughtful design, reliable infrastructure, and solid test coverage.

Room to Grow


Whether it’s Go, DevOps, mentoring, or scaling architecture — we support your professional growth and learning goals.

Life at 3Сommas

3Commas is a complete crypto-asset management platform offering a unified access point and interface with the worlds' major crypto exchanges. Fully automated trade execution and portfolio management, supported by continuously evolving strategies, algorithms and risk management solutions. By simply connecting their exchange API to 3commas, users can instantly access a unified dashboard serving as the central hub for trading and portfolio management execution Social trading makes it possible for new users to realize profits within 10 minutes of connecting to 3commas Subscriptions: 3 levels of subscriptions: $30 - $50 - $100/month offering various number of trades and bot access Fee/Trade Users have the option to experience our “smart trade” features without subscribing but paying fees equal to 0.25% of profits Enterprise Partners: Revenue sharing of success-based fees charged in addition to monthly subscriptions For additional information please email: connect@3commas.io
Thrive Here & What We Value1. Flexible working conditions with priority to work from our offices in Barcelona or Tallinn (or Nicosia).2. Inhouse lessons for crypto-trading skills.3. Competitive salary offers based on your skills.4. Paid annual leave and paid sick leave.5. Generous paid time off policy, including annual leave and sick days.6. Opportunity to shape the future of institutional crypto asset management at a leading fintech company.7. Professional development budget for conferences, courses, and certifications.8. Inspiring leadership and knowledgeable, creative, genuinely kind colleagues.9. Comfortable and cozy office in the heart of Tallinn.10. Regular corporate events, both in and out of the office, including sports activities.

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