Question: Does DynamoDB support load balancing?

Answer

You don't need to, and you can't put a load balancer in front of a table. DynamoDB balances load internally: your application calls a Regional HTTPS endpoint, and DynamoDB routes each request to the partition that stores the item's key, adding capacity and partitions as traffic grows. There are no servers or instances for you to see or route to.

What actually spreads the load:

• Partition key design. DynamoDB hashes the partition key to place items on partitions. A key with many distinct values and even access, such as a user ID, spreads traffic. A key like an order status or today's date funnels it into a few partitions. This is the part you control.
• Automatic scaling. On-demand tables absorb up to double their previous peak traffic instantly. DynamoDB also splits busy partitions (split for heat) and uses adaptive capacity to isolate hot items.
• Per-partition limits. Each partition serves up to 3,000 read units and 1,000 write units per second. A single very hot key can therefore throttle even when the table as a whole has spare capacity.

What you can add when one key is too hot:

• DynamoDB Accelerator (DAX) to serve repeated reads of hot items from memory.
• Write sharding: append a suffix such as #0 to #9 to a hot partition key, spread writes across the variants, and query all of them when reading.
• For multi-Region traffic, global tables with Amazon Route 53 latency-based or failover routing in front of your application tier, not in front of DynamoDB itself.

For throttling, inspect ThrottlingReasons: hot partitions, provisioned capacity, account quotas and configured on-demand limits require different fixes. DynamoDB throttling shows how to find the key with CloudWatch Contributor Insights, and DynamoDB partition key covers key design.

Source: AWS DynamoDB documentation.