An article on Hacker News details the process of scaling a system from zero to millions of users. The author, who worked at big tech companies and built their own startup, outlines seven distinct stages. The core principle stresses starting simple and iteratively improving based on identified bottlenecks, rather than over-engineering from the start.

The initial stage involves a single server handling everything, suitable for the first 100 users. As traffic grows, separating the database from the application server becomes necessary. This two-tier architecture offers resource isolation and independent scaling. Many teams leverage managed database services like AWS RDS or Google Cloud SQL for easier management.

Another important consideration at this stage is connection pooling. Tools like PgBouncer can improve connection efficiency. The article also mentions the trade-offs of each stage. Understanding this progression is valuable for anyone involved in software development, whether preparing for system design interviews or simply interested in how large systems operate.