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Metabase

Metabase is an open source analytics/BI platform that provides intuitive data visualization and exploration capabilities. This guide details how to connect Metabase to both local DuckDB databases and MotherDuck.

Metabase is an open source analytics and BI platform for data visualization and exploration. Connect it to MotherDuck in one of two ways:

Metabase Cloud​

Preview

The Postgres endpoint is in preview. Features and behavior may change.

Metabase Cloud does not support installing custom drivers like the DuckDB plugin. Instead, connect Metabase Cloud to MotherDuck using the Postgres endpoint. You must set two connection options so that Metabase syncs your schema correctly — see Required connection options below.

Prerequisites​

Connect to MotherDuck​

  1. In Metabase, go to Admin > Databases and click Add database (or edit an existing connection).
  2. Set the Database type to PostgreSQL and fill in the connection details:
FieldValue
Display nameMotherDuck (or any name you prefer)
HostYour MotherDuck Postgres host (for example, pg.us-east-1-aws.motherduck.com). Find yours at MotherDuck Postgres settings.
Port5432
Database nameYour MotherDuck database name
Usernamepostgres
PasswordYour MotherDuck access token
  1. Scroll down and enable Use a secure connection (SSL).
  2. If you have a company or your own SSL certificate you can set SSL Mode to verify-full and use this. Otherwise, we'll use the Let's Encrypt certificate authority and set SSL Mode to verify-ca.
  3. For the SSL Root Certificate (PEM), select Uploaded file path and upload the Let's Encrypt ISRG Root X1 certificate (isrgrootx1.pem).
Metabase connection details showing host, port, database name, username, and password fieldsMetabase SSL settings showing verify-ca mode and isrgrootx1.pem certificate
  1. Click Show advanced options, then:
  2. Click Save changes.
Metabase advanced options with the required connection string in Additional JDBC connection string options and Allow unfolding of JSON columns turned off

Required connection options​

In the Additional JDBC connection string options field, set:

options=-c%20attach_mode%3Dsingle%20-c%20compatibility_mode%3Dmetabase

This is a single options= value that passes two Postgres startup options to MotherDuck. It decodes to -c attach_mode=single -c compatibility_mode=metabase, where:

  • compatibility_mode=metabase makes MotherDuck return catalog metadata in the exact shape Metabase expects. Without it, Metabase's field-sync query fails on recent Metabase versions and tables sync with no fields ("Table has no Fields associated with it").
  • attach_mode=single scopes the connection to the database you connect to, instead of every database in your account. This keeps schema-sync queries light and lets Metabase populate table row-count estimates.
warning

Enter the value exactly as shown, fully URL-encoded: %20 for each space and %3D for each =. If you separate the two options with a literal space or &, or leave the inner = un-encoded, Metabase keeps only the first option and silently drops attach_mode=single during sync.

JSON columns​

Turn off Allow unfolding of JSON columns in the connection's advanced options. When unfolding is enabled, Metabase expands JSON columns into virtual fields and queries them with the PostgreSQL #>> path operator, which the Postgres endpoint does not support — those questions fail. With unfolding off, JSON columns sync as regular fields and everything else works.

Known limitations​

Foreign-key relationships and indexes do not sync automatically over the Postgres endpoint, so the query builder's implicit (automatic) joins are unavailable. Tables, fields, types, primary keys, comments, and row counts all sync normally, and explicit joins in native SQL or the query builder work. To use relationships in the query builder, define them manually under Admin > Table Metadata by setting a field's type to Foreign Key and choosing its target.

Troubleshooting​

SymptomResolution
Tables sync but have no fields ("Table has no Fields associated with it")Confirm compatibility_mode=metabase is present in Additional JDBC connection string options, and that the value is fully URL-encoded (%20/%3D) exactly as shown. Then re-sync the database schema.
Schema browsing shows tables from other databases, or row counts are missingConfirm attach_mode=single is present in the options string. It is silently dropped if the value uses a literal space or & between the options, or leaves the inner = un-encoded.
A question on a JSON field fails to runTurn off Allow unfolding of JSON columns and re-sync (see JSON columns).
No relationships / implicit joins in the query builderExpected — define foreign keys manually under Admin > Table Metadata (see Known limitations).

Self-hosted Metabase​

Self-hosted Metabase can connect to MotherDuck in two ways: install the DuckDB driver plugin (described below), or connect through the Postgres endpoint using the same steps as Metabase Cloud. The DuckDB driver runs queries in Metabase's embedded DuckDB and also supports local DuckDB files and DuckLake; the Postgres endpoint routes queries to MotherDuck without a plugin.

Prerequisites​

Install the DuckDB driver​

  1. Create a Dockerfile that includes the latest Metabase plus the DuckDB driver:
FROM eclipse-temurin:21-jre

ENV MB_PLUGINS_DIR=/plugins
RUN mkdir -p ${MB_PLUGINS_DIR} /app

# Latest Metabase
ADD https://downloads.metabase.com/latest/metabase.jar /app/metabase.jar

# Latest DuckDB driver
ADD https://github.com/MotherDuck-Open-Source/metabase_duckdb_driver/releases/latest/download/duckdb.metabase-driver.jar ${MB_PLUGINS_DIR}/

EXPOSE 3000
CMD ["java", "-jar", "/app/metabase.jar"]
  1. Build and run:
docker build -t metabase-duckdb:latest .
docker run -d --name metaduck -p 3000:3000 -e MB_PLUGINS_DIR=/plugins metabase-duckdb:latest

Tip: For reproducible builds, pin versions instead of latest:

# Example of pinning versions (replace X.Y.Z)
ADD https://downloads.metabase.com/vX.Y.Z/metabase.jar /app/metabase.jar
ADD https://github.com/MotherDuck-Open-Source/metabase_duckdb_driver/releases/download/1.X.Y/duckdb.metabase-driver.jar ${MB_PLUGINS_DIR}/

Note: Use a Debian/Ubuntu-based JRE image (not Alpine) to avoid glibc issues with the DuckDB driver.

important

Restart required: Metabase must be restarted after adding or upgrading plugins. Hot-reload of drivers is not supported.

tip

Compatibility and upgrades: New DuckDB driver releases are designed to be backward compatible with recent Metabase versions. Upgrading to the latest driver is recommended for bug fixes and stability. If you run a significantly older Metabase version, validate in staging first.

Add your database connection​

After installing the driver, you can add MotherDuck as a data source in Metabase.

  1. Log in to Metabase with admin credentials
  2. Navigate to Admin Settings > Databases > Add Database
  3. Select DuckDB as the database type
note

Since DuckDB does not do implicit casting by default, the old_implicit_casting config is necessary for datetime filtering in Metabase to function. It's recommended to keep it set.

Connecting to MotherDuck​

To connect to MotherDuck:

  1. Database name: In the Database file field, enter md:[database_name] where [database_name] is your MotherDuck database name
  2. MotherDuck token: Paste your MotherDuck token (retrieve from the MotherDuck UI)
  3. Configuration: Enable old_implicit_casting (recommended) for proper datetime handling

Metabase connection settings for MotherDuck

DuckLake on Metabase​

DuckLake is supported with the DuckDB driver in Metabase. Use the latest DuckDB driver release and a DuckDB version that supports DuckLake (DuckDB v1.3.2 or newer is recommended).

MotherDuck-managed DuckLake​

If your DuckLake database is managed by MotherDuck, you can connect the same way you connect to any MotherDuck database:

  1. Select DuckDB as the database type
  2. Database file: md:[ducklake_database_name]
  3. MotherDuck token: paste your token
  4. Keep old_implicit_casting enabled (recommended)

No extra Init SQL is required. Query your tables normally in Metabase.

Own compute + DuckLake catalog (attach in init SQL)​

If you want Metabase’s embedded DuckDB to query a DuckLake stored externally, attach the DuckLake catalog in the connection’s Init SQL. This works for both MotherDuck-managed catalogs and self-managed catalogs.

  • Init SQL for a MotherDuck-managed DuckLake catalog:
-- Attaches the DuckLake metadata catalog hosted in MotherDuck
ATTACH 'ducklake:md:__ducklake_metadata_[database_name]' AS dl1;
  • Init SQL for a self-managed DuckLake catalog (local metadata DB) with S3 data path:
-- Replace the path to your DuckLake metadata DB and bucket prefix
ATTACH 'ducklake:/duckdb/my_ducklake_metadata.ducklake' AS dl1 (
  DATA_PATH 's3://my_bucket/lake/'
);

Once attached, reference tables with the alias, for example: FROM dl1.my_table.

Connecting to a local DuckDB database​

To connect to a local DuckDB database:

  1. Database file: enter the full path to your DuckDB file (e.g., /path/to/database.db)
  2. Configuration: enable old_implicit_casting (recommended) to ensure proper datetime filtering
note

DuckDB's concurrency model supports either one process with read/write permissions, or multiple processes with read permissions, but not both at the same time. This means you will not be able to open a local DuckDB in read-only mode, then the same DuckDB in read-write mode in a different process.

Metabase connection settings for local DuckDB

Configuration best practices​

  • Connection pooling: For production instances, set an appropriate connection pool size based on expected concurrent users
  • Query timeouts: Configure timeouts in Metabase settings to prevent long-running queries from affecting system performance
  • Data access: Use database-level permissions in Metabase to control who can access which data sources

Troubleshooting​

IssueSolution
Driver not detectedEnsure driver is in the correct plugins directory and Metabase has been restarted
Connection failuresVerify database path (local) or database name and token (MotherDuck)
Permission errorsCheck file permissions for local databases
Datetime filtering issuesEnable old_implicit_casting in the connection settings
Add MotherDuck token in the connection stringSpecify a correct MotherDuck token or MotherDuck database name after the md: prefix

Updating the MotherDuck token​

Metabase keeps long-lived database connections alive. When you update only the MotherDuck token while an existing connection is still cached, Metabase raises Connection error: Can't open a connection to same database file with a different configuration than existing connections.

Use one of the following approaches to refresh the token successfully:

  1. Add a cache buster while editing the database. Edit the connection under Admin Settings > Databases, then update both the Database file field and the MotherDuck Token field with a small cache-busting change (for example, append ?refresh=20250917). Updating both values at the same time forces Metabase to treat the configuration as new. Save the connection, then optionally revert the fields to their clean values once the change is persisted.

  2. Restart Metabase before updating the token. Restart the Metabase service and, immediately after it starts, go straight to /admin/databases to update the token field. Do not open the Metabase home screen before editing the database connection, or the previous connection (with the old token) will be re-established.

Connecting to a local DuckDB database​

To connect to a local DuckDB database:

  1. Database file: Enter the full path to your DuckDB file (e.g., /path/to/database.db)
  2. Configuration: Enable old_implicit_casting (recommended) to ensure proper datetime filtering
  3. Additional settings:
    • Read only: Toggle as appropriate for your use case
    • Naming strategy: Choose your preferred table/field naming strategy
note

DuckDB's concurrency model supports either one process with read/write permissions, or multiple processes with read permissions, but not both at the same time. This means you will not be able to open a local DuckDB in read-only mode, then the same DuckDB in read-write mode in a different process.

Metabase connection settings for local DuckDB