Step 3: Capacity Estimation

One figure shapes this design more than any other: about a billion votes a day, against roughly a million new posts. The estimates below derive it and the other numbers the later steps depend on, and the diagram summarizes them.

Users. About 500 million people use the platform monthly (MAU) and about 10 million daily (DAU), so hundreds of thousands are active at any moment.

Read/write ratio. About 95 percent of operations are reads, like browsing posts and comments, and about 5 percent are writes, like posting, commenting, and voting