How Replit makes sense of code at scale

Replit has built an infrastructure that leverages rich coding data to answer critical questions about user behavior on its platform. The company stores over 300 million software repositories and uses Operational Transformation (OT) to create a granular understanding of project timelines, execution data, and error stack traces. To make sense of this data, Replit developed a custom solution called Backer, which is an ETL layer that extracts updates from users' projects in case anything goes wrong. The system decouples responsibilities, is distributed by design, and reduces bottlenecks in computing, latency, and egress costs. Backer then feeds its results into a Progressive Classification design, which uses progressively more precise filters to classify coding data. This approach balances cost and insight depth, enabling Replit to provide powerful insights on user behavior and build a better product. The company's solution is generalizable to other industries and domains, making it an attractive example for companies looking to extract value from their petabytes of unstructured information.