Senior Full-Stack Engineer (BE)

3Commas.io is a leading developer of cryptocurrency trading software, building the leading automation platform for crypto trading—turning complex markets into simple yet powerful algorithmic strategies. Our AI-driven bots (DCA, Grid, Signal), deep integrations with TradingView, and a robust API enable traders to automate and optimize across 15+ major exchanges, including Binance, Coinbase, OKX, and Bybit. We serve a global community of individual and institutional traders and developers who rely on our security-first, reliable, and battle-tested infrastructure to run strategies 24/7. Join us to build tools that power real trading volume, tackle hard product and engineering problems at scale, and make pro-level trading accessible to everyone.

Role Overview

As a Senior Fullstack Engineer, you will work on our high-load trading platform that connects to 15+ exchanges and powers manual and automated strategies with DCA, Grid, and Signal bots. You’ll build and own complex features end-to-end on a modern stack.

• 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.

• 4+ years of experience in Ruby on Rails backend development.
• Proven experience with React and TypeScript.
• 6+ years of proven full-stack commercial development experience.
• Strong knowledge of PostgreSQL and relational modeling at scale: large tables, replication, partitioning, multi‑DB per app, query planning and indexing.
• Hands-on approach to software engineering best practices: TDD, refactoring, code review, and system design.
• Familiarity with AWS  services (e.g., Lambda, DynamoDB).
• Hands-on experience with key-value stores (Redis, Memcached, etc.).
• Experience integrating third-party APIs and services.
• 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.

• 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.

🔧 Impact at Scale
Drive product innovation for a platform used by millions of traders and developers worldwide.

🧭 Strategic Influence
Shape the product roadmap and user experience alongside executive leadership.

🧠 Culture of Growth
Join a passionate, talented team where ideas are valued, and careers are accelerated.

🌍 Global & Remote
Work flexibly from Barcelona, Tallinn, Cyprus — or remotely, in sync with our distributed product and tech teams.

3Commas.io is proud to be an equal opportunity employer. We believe diversity fuels innovation and welcomes applications from individuals of all backgrounds, identities, and experiences — regardless of race, gender, age, religion, disability, or sexual orientation.