Suggest an editImprove this articleRefine the answer for “Why does MongoDB scale horizontally?”. Your changes go to moderation before they’re published.Approval requiredContentWhat you’re changing🇺🇸EN🇺🇦UAPreviewTitle (EN)Short answer (EN)Because MongoDB was designed from the start so that data could be split into pieces and stored across several servers instead of one: it uses replication and sharding mechanisms to distribute and store data across a cluster, routing requests through mongos. **Key point:** the client doesn't need to know "where the data lives" - the router itself sends the request to the right shard, so the database isn't limited by the power of a single server, and new machines can be added as load grows.Shown above the full answer for quick recall.Answer (EN)ImageBecause MongoDB was designed from the start so that **data could be split into pieces and stored across several servers**, instead of just one. It uses replication and sharding mechanisms to distribute and store data across a cluster. ### The key reasons 1. **Data can be split into shards** A collection is split by its `shard key`, and each piece goes to its own server. That means load doesn't concentrate in one place. 2. **There's no tie to a single machine** Unlike many SQL systems, MongoDB can behave as a single database even when the data physically lives on dozens of nodes. 3. **Requests are routed through mongos** The client doesn't have to think about "where the data lives", the router itself sends the request to the right shard. ### What this gives you - the database isn't limited by a single server's power - new machines can be added as load grows - reads and writes get spread across nodes ### Summary MongoDB scales horizontally because it can **distribute data and load across many servers**, while still looking like a single logical database.For the reviewerNote to the moderator (optional)Visible only to the moderator. Helps review go faster.