AWS Shipped a DynamoDB API That Stores Everything in Postgres. Read the Tables It Writes

On May 20, 2026, AWS unveiled ExtendDB, an open-source server that adheres to the DynamoDB wire protocol and stores all data in PostgreSQL. This innovative project allows users to interact with DynamoDB through a PostgreSQL database interface, enabling them to view and manipulate the stored items using traditional SQL tools. Written in Rust, ExtendDB is maintained by AWS and described in its README as a clean-room implementation of the DynamoDB wire protocol.

As of now, the project is at version 0.1.13, although it is still in its early stages. ExtendDB supports a wide range of DynamoDB features, including tables, items, querying and scanning, batch and transactional writes, streams, time-to-live (TTL), and vector search using the pgvector extension. The project is compatible with PostgreSQL 14 and above, as well as MongoDB and SQLite.

TLS is mandatory, and every request must be SigV4-signed with credentials issued by ExtendDB itself. The project provides a Docker Compose file that simplifies the setup process, allowing users to run PostgreSQL 16 and ExtendDB side by side using Docker Compose. To get started, users can clone the repository, build the Docker Compose image, and execute the bootstrap script, which creates an account ID, admin password, and a user with full access permissions.

Access keys are then generated, and the self-signed certificate is configured. With these credentials, users can authenticate with the stock AWS CLI, pointing it at the ExtendDB server using the endpoint URL and certificate file. Once configured, users can perform operations such as listing tables and creating indexes, as demonstrated in the example provided.

ExtendDB's single-table design allows for a small shop scenario, where customers and their orders share a partition and a Global Secondary Index (GSI) is used to answer queries about orders in a specific status. The example shows how to create a table and populate it with items using the AWS CLI and the ExtendDB API.