Backend Engineer

We are looking for a Backend Engineer with 3+ years of experience to own and evolve the critical data processing pipeline at Replay, the primary source of real, proprietary enterprise data for the world's leading frontier AI labs. You'll join a small but mighty engineering team of five, backed by a multi-eight-figure run rate and massive demand from customers like the top frontier labs, RL gyms, and data labeling companies. We need someone who has personally shipped and operated production backend systems, thrives in a fast-moving startup environment, and brings a strong sense of ownership. Ideally you've worked at both a strong-name company and an early-stage startup, and you hold a degree from a top STEM program. This is a high-impact, ground-floor opportunity to shape engineering culture at one of the fastest-scaling companies in AI data.

What will you be doing?

• Building and scaling multi-stage, high-volume data processing pipelines that de-identify sensitive enterprise data (Slack exports, Gmail, Google Drive, codebases, project management tools) and make it AI-training ready
• Owning backend systems end-to-end — design, delivery, debugging, correctness verification, and safe recovery — ensuring silent failures, duplicated output, and stale data are caught before customer delivery
• Making retries, checkpoints, partial failures, replay, backfills, and rollbacks safe and understandable across asynchronous orchestration, batch workers, queues, and object storage
• Building internal tooling and dashboards to understand pipeline performance, investigate data quality, and support release decisions with queryable provenance
• Collaborating closely with ML, full-stack, platform, and security teammates to process new data modalities and expand the pipeline's capabilities