Cloud-native, serverless & distributed SQL
Amazon Aurora PostgreSQL Limitless Database vs Azure Database for PostgreSQL elastic clusters / Azure Cosmos DB for PostgreSQL
Aurora PostgreSQL Limitless Database maps to elastic clusters in Azure Database for PostgreSQL, which is managed Citus.
Azure Cosmos DB for PostgreSQL, the older Citus service, is on a retirement path.
Side-by-side comparison
| Aspect | Amazon Web Services | Microsoft Azure |
|---|---|---|
| Service | Amazon Aurora PostgreSQL Limitless Database | Azure Database for PostgreSQL elastic clusters Azure Cosmos DB for PostgreSQL Deprecated |
| Lifecycle | Generally available | Generally available On a retirement path and not recommended for new projects. Microsoft points to elastic clusters in Azure Database for PostgreSQL. |
| What it is | Automated horizontal sharding for Aurora PostgreSQL, spreading data and writes across shards while you connect to a single database endpoint. | Managed Citus on flexible server nodes, for horizontal sharding (row-based or schema-based) across a shared-nothing cluster. Distributed PostgreSQL built on Citus. |
| Pricing model | Billed per ACU-hour of the shard group (serverless capacity) plus Aurora storage and I/O. | Each node is billed like a flexible server (vCore-hours plus storage). |
| Docs | Amazon Aurora PostgreSQL Limitless Database docs | Azure Database for PostgreSQL elastic clusters docs Azure Cosmos DB for PostgreSQL docs |
| Pricing page | Amazon Aurora PostgreSQL Limitless Database pricing | Azure Database for PostgreSQL elastic clusters pricing Azure Cosmos DB for PostgreSQL pricing |
| Exams | SAP-C02 Retiring | AZ-305 |
Key differences
- Engine. Limitless is AWS-built sharding on Aurora's storage. Elastic clusters use the open-source Citus extension on flexible server nodes in a shared-nothing cluster.
- Sharding models. Elastic clusters support row-based and schema-based sharding. Limitless uses sharded and reference tables behind a router layer.
Pricing summary
Pricing models only. No prices are quoted because they change by region and over time.
- AWS
- Billed per ACU-hour of the shard group (serverless capacity) plus Aurora storage and I/O. Amazon Aurora PostgreSQL Limitless Database pricing →
- Azure
- Each node is billed like a flexible server (vCore-hours plus storage). Azure Database for PostgreSQL elastic clusters pricing → Azure Cosmos DB for PostgreSQL pricing →
Certification exam mapping
| Exam | Provider | Level | Status |
|---|---|---|---|
| AWS Certified Solutions Architect – Professional SAP-C02 | AWS | Professional | retiring Being updated to SAP-C03. Registration for SAP-C03 opens Oct 27, 2026. Last day to take SAP-C02 is Nov 16, 2026. |
| Microsoft Certified – Azure Solutions Architect Expert AZ-305 | Azure | Expert | current English version updated Apr 17, 2026. |
Relevance is based on each exam's published scope, not a line-by-line objective match. Check the official study guide.
FAQ
What is the Azure equivalent of Amazon Aurora PostgreSQL Limitless Database?
Aurora PostgreSQL Limitless Database maps to elastic clusters in Azure Database for PostgreSQL, which is managed Citus. Azure Cosmos DB for PostgreSQL, the older Citus service, is on a retirement path.
How does pricing compare between Amazon Aurora PostgreSQL Limitless Database and Azure Database for PostgreSQL elastic clusters and Azure Cosmos DB for PostgreSQL?
AWS: Billed per ACU-hour of the shard group (serverless capacity) plus Aurora storage and I/O. Azure: Each node is billed like a flexible server (vCore-hours plus storage). Check the official pricing pages for current rates.
Which certification exams cover this topic?
AWS Certified Solutions Architect – Professional (SAP-C02) [retiring]; Microsoft Certified – Azure Solutions Architect Expert (AZ-305).