Overview

DuckDB has a flexible extension mechanism that allows for dynamically loading extension. These may extend DuckDB's functionality by providing support for additional file formats, introducing new types, and domain-specific functionality.

Extensions are loadable on all clients (e.g., Python and R). Extensions distributed via the official repository are built and tested on MacOS (AMD64 and ARM64), Windows (AMD64) and Linux (AMD64 and ARM64).

We maintain a list of official extensions.

Using Extensions

Listing Extensions

To get a list of extensions, run:

FROM duckdb_extensions();

┌────────────────┬─────────┬───────────┬──────────────┬────────────────────────────────────────────┬───────────┐
│ extension_name │ loaded  │ installed │ install_path │                description                 │  aliases  │
│    varchar     │ boolean │  boolean  │   varchar    │                  varchar                   │ varchar[] │
├────────────────┼─────────┼───────────┼──────────────┼────────────────────────────────────────────┼───────────┤
│ autocomplete   │ true    │ true      │ (BUILT-IN)   │ Add supports for autocomplete in the shell │ []        │
| ...            | ...     | ...       | ...          | ...                                        |           |
└────────────────┴─────────┴───────────┴──────────────┴────────────────────────────────────────────┴───────────┘

Extension Types

DuckDB has three types of extensions.

Built-In Extensions

Built-in extensions are loaded at startup and are immediately available for use.

SELECT * FROM 'test.json';

This will use the json extension to read the JSON file.

To make the DuckDB distribution lightweight, it only contains a few fundamental built-in extensions (e.g., autocomplete, json, parquet), which are loaded automatically.

Autoloadable Extensions

Autoloadable extensions are loaded on first use.

SELECT * FROM 'https://raw.githubusercontent.com/duckdb/duckdb-web/main/data/weather.csv';

To access files via the HTTPS protocol, DuckDB will automatically load the httpfs extension. Similarly, other autoloadable extensions (aws, fts) will be loaded on-demand. If an extension is not already available locally, it will be installed from the official extension repository (extensions.duckdb.org).

Explicitly Loadable Extensions

Some extensions make several changes to the running DuckDB instance, hence, autoloading them may not be possible. These extensions have to be installed and loaded using the following SQL statements:

INSTALL spatial;
LOAD spatial;

CREATE TABLE tbl(geom GEOMETRY);

Extension Handling through the Python API

If you are using the Python API client, you can install and load them with the install_extension(name: str) and load_extension(name: str) methods.

Autoloadable extensions can also be installed explicitly.

Ensuring the Integrity of Extensions

Extensions are signed with a cryptographic key, which also simplifies distribution (this is why they are served over HTTP and not HTTPS). By default, DuckDB uses its built-in public keys to verify the integrity of extension before loading them. All extensions provided by the DuckDB core team are signed.

If you wish to load your own extensions or extensions from third-parties you will need to enable the allow_unsigned_extensions flag. To load unsigned extensions using the CLI client, pass the -unsigned flag to it on startup.

Installation Location and Sharing Extensions between Clients

Extensions are by default installed under the user's home directory, to ~/.duckdb/extensions/{DuckDB version}/{Platform name}. For example, the extensions for DuckDB version 0.9.0 on macOS ARM64 (Apple Silicon) are installed to ~/.duckdb/extensions/v0.9.0/osx_arm64.

The shared installation location allows extensions to be shared between the client APIs of the same DuckDB version. For example, if an extension is installed with version 0.9.0 of the CLI client, it is available from the Python, R, etc. client libraries provided that they have access to the user's home directory and use DuckDB version 0.9.0.

To specify a different extension directory, use the extension_directory configuration option:

SET extension_directory=/path/to/your/extension/directory

For development builds, the directory of the extensions corresponds to the Git hash of the build, e.g., ~/.duckdb/extensions/fc2e4b26a6/linux_amd64_gcc4.

Developing Extensions

The same API that the official extensions use is available for developing extensions. This allows users to extend the functionaly of DuckDB such to suit their domain the best. A template for creating extensions is available in the extension-template repository.

Working with Extensions

For more details, see the Working with Extensions page.