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DynamoDB – Read/Write Capacity Modes

Controls how you manage a table’s throughput.

Provisioned Mode (default)

  • You define the number of reads and writes per second.
  • Requires capacity planning in advance.
  • Billing is based on:
    • Read Capacity Units (RCU)
    • Write Capacity Units (WCU)
  • Supports Auto Scaling to adjust RCU/WCU automatically.
  • More cost-effective for steady, predictable workloads.

On-Demand Mode

  • Automatically adjusts capacity in response to workload.
  • No upfront planning required.
  • Pay-per-request pricing model (can be more expensive for sustained high traffic).
  • Best suited for:
    • Unpredictable traffic patterns
    • Sudden, large spikes in usage
The choice depends on whether your workload is predictable (use Provisioned) or unpredictable (use On-Demand).