Senior Fullstack Engineer

At Upside, we’re partnering with ambitious companies across the globe to solve complex, meaningful problems through technology. We work in focused teams, combining engineering, product thinking, and design, to deliver outcomes, not just output.

Open-source is a strategic part of our work. We build and maintain a number of open-source projects that support our clients and internal R&D. Our latest release is Enthusiast, a customizable agentic AI toolkit for e-commerce.

What it means for you 

You’ll have a "Founder" mindset. You won’t just build a UI or a database - you’ll own the entire product experience. You’ll be a technical partner to stakeholders, helping them understand what’s possible with modern tech and AI. You’ll have the autonomy to experiment across the stack and the responsibility to deliver tools that actually solve business problems.

You’ll work at the intersection of product thinking and engineering, deploying AI-augmented features across the entire stack.

Role Overview 

As a Senior Fullstack Engineer, you’ll design and scale resilient systems from the ground up. You’ll bridge the gap between backend logic and frontend experience, ensuring a seamless, production-grade product.

Responsibilities

• End-to-End Ownership: Lead the design and implementation of both backend systems and frontend interfaces.

• Proactive Solutions: Don't just flag blockers—come with proposals and experiments to bypass them.

• Consulting: Translate complex business needs into elegant, scalable fullstack architecture.

• Engineering Standards: Advocate for code quality, security, and performance across the entire repo.

• Continuous Improvement: Constantly evaluate new tech (especially AI/LLM) to improve delivery.