Principal Engineer, Ads Platform

Meet Fetch Engineering

At Fetch, engineering is driven by curiosity, ownership, and a bias toward action. We operate in complex problem spaces where the right answer is not always clear, and success depends on adaptability, critical thinking, and informed decision‑making. Our engineers are comfortable navigating ambiguity, understanding trade‑offs, gathering context, and turning uncertainty into progress while maintaining high technical standards.

Engineers at Fetch take pride in building reliable, scalable systems that serve millions of users. You will contribute directly to the codebase, collaborate closely with cross‑functional partners, and help shape best practices that elevate the quality of our work. We foster a culture of mentorship and collaboration, where engineers grow by learning from one another and holding a high bar for quality, reliability, and impact.

Fetch is building the next generation of systems that power personalized advertising experiences for millions of users, and we’re looking for a Principal Backend Engineer to help define the architecture behind them. You will design, scale, and evolve the high‑throughput, low‑latency distributed systems that sit on the critical path of Fetch's advertising platform. These systems must make decisions and serve experiences in real time while maintaining exceptional standards for availability, correctness, efficiency, and operational resilience.

At Fetch, Principal is the most senior individual‑contributor engineering level, and only a small number of engineers operate here. You set technical direction the rest of engineering builds on, act as a technical peer to engineering leadership, and are the person brought in for the cross‑organizational problems that have stalled major company initiatives and that no one else has solved. You own the long‑term engineering strategy for the Ads platform and drive the fundamental technical shifts, major migrations, and architectural redesigns that unlock gains for the entire engineering organization.

The role requires deep expertise in distributed systems and backend architecture, along with a track record of solving difficult scaling problems in production. You should be comfortable reasoning about systems operating at very high request volumes, identifying bottlenecks across the stack, and designing architectures that continue to perform as traffic, data volume, and product complexity grow.

This is a hands‑on, high‑impact technical leadership role with influence across multiple engineering collectives. You stay in the code while operating at Principal scope, moving between architecture, implementation, debugging, strategy, and mentorship, and your work shapes how Fetch approaches distributed systems, service architecture, performance, reliability, and engineering excellence at scale.

This is a full‑time role that can be held from one of our US offices or remotely in the United States.

• Own the platform architecture. Define the architecture of the high‑throughput, low‑latency systems behind ad selection, targeting, pacing, delivery, attribution, and measurement, including the calls on partitioning, caching, consistency, concurrency, and performance as the platform scales.
• Design for reliability, resilience, and operational excellence. Set how systems degrade gracefully under partial failures, traffic spikes, and downstream degradation, and establish the metrics, tracing, SLOs, and alerting that give engineering clear visibility into revenue‑generating systems.
• Evolve event‑driven and data‑intensive architectures. Guide decisions across transactional and non‑transactional stores, streaming, messaging, caching, and real‑time processing,…