Senior Backend Engineer

Overview

As a Senior Backend Engineer, you’ll design, build, and scale core backend systems that power high-traffic consumer products and internal platforms. You’ll own foundational services and APIs, work on high-throughput distributed systems, and partner closely with product, ML, and engineering teams to deliver reliable, low-latency experiences at scale.

Phia has raised $43M from Notable Capital, Khosla Ventures, and Kleiner Perkins to build the AI alignment layer for commerce. In under a year, Phia’s consumer shopping agent has surpassed one million users and partnered with 6,200+ retail brands, representing billions in annual gross merchandise volume. Each month, Phia drives millions of dollars in sales for brands and has achieved 11× revenue growth since launch.

In an era where AI vertical agents are reshaping every industry, commerce is on the verge of a complete transformation. Phia is reinventing shopping from a fragmented, impersonal experience into one that feels intelligent, trusted, and built around each user’s intent. This foundation of trust is our wedge to become the end-to-end shopping destination for the next generation of buyers.

Phia is a lean, high-ownership team building at startup speed. If you want to ship at high velocity and solve complex problems in consumer AI and commerce, this is the place to do it.

• Design and build scalable backend services, APIs, and shared platform components

• Own system architecture, performance, and reliability for core backend systems

• Partner with product and ML teams to support data- and model-driven workflows

• Improve observability, monitoring, and operational best practices

• Drive technical decisions and contribute to long-term platform strategy

• Raise the quality bar through code reviews, design discussions, and mentorship

• 5+ years of experience building and operating backend systems in production

• Strong experience with APIs, databases, and distributed systems

• Proficiency in at least one backend language and modern backend frameworks

• Experience designing systems for scale, performance, and reliability

• Strong ownership mindset and ability to work in fast-moving environments

• Clear communicator who collaborates well across functions