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Middle Backend Engineer

3СommasTallinn, Estonia | Barcelona, Spain | WorldwideOnsite

3Commas is a leading platform for crypto trading automation. We’re building a modular SaaS product that helps traders worldwide scale their strategies, connect with exchange APIs, and automate routine tasks.
We’re looking for a backend engineer with strong Ruby on Rails experience and a product-oriented mindset. You’ll be responsible for designing secure, scalable features, integrating external APIs, and ensuring performance and 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.
  • Integrate external API services and ensure their secure and stable operation.
  • Take ownership of your code in production: monitoring, alerting, and ongoing support.
  • Participate in QA processes from the early stages (“shift-left” approach).
  • Contribute to code quality through automated tests, code reviews, and refactoring.
  • Actively collaborate with cross-functional teams, including DevOps and QA.
  • Stay up to date with best practices in backend architecture, security, and performance.

Requirements:


  • 4+ years of experience in backend development with Ruby on Rails.
  • Strong understanding of PostgreSQL and relational data modeling.
  • Familiarity with AWS serverless services (e.g., Lambda, DynamoDB).
  • Experience with key-value storage (Redis, Memcached, etc.).
  • Solid grasp of software development best practices: TDD, CI, clean code, refactoring.
  • Experience integrating external APIs and handling third-party service interactions.
  • Understanding of security, scalability, and performance concerns in backend systems.
  • Willingness to engage in testing and QA — quality is everyone’s responsibility.
  • Comfortable working in Agile teams and participating in code reviews and planning.
  • English proficiency at B2 level or higher (written & spoken).

Nice to Have:


  • Basic experience with Go and interest in expanding your skills in it.
  • Knowledge of Kubernetes and microservice orchestration.
  • Familiarity with Kafka, RabbitMQ or other messaging/streaming systems.
  • Experience solving high-load challenges and performance bottlenecks.
  • Hands-on experience with observability tools (Grafana, CloudWatch, etc.).

What We Offer:


  • Product & Architecture OwnershipShape a scalable SaaS product — not just write code, but make decisions that impact performance, quality, and business value
  • Modern Tech Stack Work hands-on with AWS Lambda, DynamoDB, Kubernetes, Redis, PostgreSQL, and integrate Go where it fits best.
  • Remote-First CultureJoin a globally distributed team with asynchronous workflows, and optional office access in Barcelona and Tallinn.
  • High Engineering StandardsWe care about clean code, test coverage, performance, and the long-term maintainability of our systems.
  • Room to GrowLearn new technologies like Go, improve your infrastructure skills, or mentor junior developers — we’ll support your evolution.

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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