: If you place replicas in different AZs (recommended for HA), cross-AZ replication traffic is charged for the data written from primary to each replica.
: You pay for every instance in the cluster. A production cluster with 1 primary + 2 replicas costs 3× the single instance price. documentdb cost
This guide breaks down exactly how you are charged and how to slash your monthly bill by up to 40%. 1. The Core Components of DocumentDB Pricing : If you place replicas in different AZs
Amazon DocumentDB is a fully managed, scalable, and highly available document database service that mimics MongoDB APIs. While it simplifies operations (backups, patching, replication), understanding its is critical to avoid unexpected bills. Unlike serverless MongoDB alternatives (e.g., Atlas Serverless), DocumentDB primarily follows an instance-based pricing model —you pay for the underlying AWS infrastructure, not per request or document. This guide breaks down exactly how you are
| Strategy | Impact | Effort | |----------|--------|--------| | – Use CloudWatch metrics; many workloads run fine on r6g (Graviton, 20% cheaper) or t3 burstable. | High | Medium | | Use Reserved Instances or Savings Plans for production workloads. | High (30–60%) | Low | | Minimize cross-AZ replicas – For non‑critical workloads, place all replicas in same AZ (lose HA but save transfer costs). | Medium | Low | | Delete idle clusters – Stop (pause) development clusters when not needed. | High | Low | | Automate snapshot cleanup – Delete old manual snapshots beyond retention period. | Low | Low | | Use Graviton2 instances ( db.r6g , db.t4g ) – Up to 20% lower price and better performance. | High | Very Low | | Enable auto-scaling for storage – Avoid over‑provisioning. | Low | Low |
Last updated: March 2025 – based on AWS us-east-1 On-Demand pricing. Check the official Amazon DocumentDB Pricing Page for current rates.