DynamoDB can handle 10 million requests per second. But there's a catch.

DynamoDB is a beast — it powers Amazon.com's shopping cart and handles peak loads during Prime Day without breaking a sweat. But its power comes with a design constraint you must understand: partition keys.

Every item in DynamoDB is stored in a partition determined by its partition key. If too many requests hit the same partition key, you get throttling — even if your overall capacity is fine. This is called a "hot partition."

The fix? Design your keys for even distribution. Don't use a date as your partition key if all traffic is for "today." Instead, add a random suffix or use a composite key. The best DynamoDB tables look boring from a data modeling perspective — but they scale effortlessly.