Senior Fullstack Engineer

Upside partners with ambitious companies globally to solve complex, meaningful problems through technology. We work in focused, small teams that combine engineering, product thinking, and design to deliver high-impact outcomes.

Key responsibilities

• Lead the design and implementation of both backend systems and frontend interfaces with end-to-end ownership.
• Translate complex business needs into elegant, scalable fullstack architecture while acting as a technical partner to stakeholders.
• Advocate for high engineering standards, including code quality, security, and performance across the entire repository.
• Proactively identify blockers and propose experiments to bypass them, ensuring continuous project momentum.
• Evaluate and integrate new technologies, particularly AI and LLM tools, to improve delivery and product capabilities.

Requirements

• 5+ years of professional experience building complex, scalable web applications.
• Strong proficiency in backend development using Python or Ruby.
• Mastery of frontend development with Vue.js or React.js.
• Solid understanding of SQL, specifically PostgreSQL, alongside CI/CD pipelines and cloud environments.
• Fluent English (C1) to facilitate direct collaboration with international clients.

What we offer

• Real ownership and accountability within small, high-impact teams where your decisions carry significant weight.
• Opportunities to work on mission-critical projects for international brands and scaling companies.
• A culture that prioritizes applied AI as a first-class discipline, including contributions to open-source projects.
• A transparent progression path with clearly defined engineering levels and criteria for growth.
• A professional environment free from micromanagement, focused on trust and delivering tangible results.