Buckets

Buckets are the object storage locations Altertable uses for lakehouse data.

You use buckets in three common places:

• Altertable catalogs store their managed data in a selected bucket.
• Bucket Tables external catalogs map logical table names to files that already live in a bucket.
• Iceberg Tables external catalogs resolve Iceberg metadata and data files from a bucket.

Every environment includes a built-in bucket so you can get started immediately. You can also connect additional buckets when you want to control the provider, region, or endpoint yourself.

Supported providers

Altertable can connect buckets from:

• Cloudflare R2
• Amazon S3
• Google Cloud Storage
• Custom S3-compatible endpoints

Connecting a bucket

1. Open your Organization Settings and select Manage in the Buckets section.
2. Click New bucket.
3. Choose the storage provider.
4. Enter the bucket name and credentials.
5. Fill the provider-specific fields when needed. Cloudflare R2 asks for an Account ID instead of a full endpoint URL, Google Cloud Storage uses Google's default endpoint automatically, and custom S3-compatible providers ask for an Endpoint.
6. Choose a region when the provider requires it, then test the connection before saving.

Once connected, the bucket becomes available anywhere Altertable asks for bucket-backed storage.

Where buckets are used

Buckets show up in two main workflows:

• Altertable catalogs: choose which bucket should store a managed catalog's files.
• External catalogs: use a connected bucket as the source for file-backed catalogs such as Bucket Tables and Iceberg Tables.

This page focuses on connecting and managing buckets themselves. The catalog pages explain how each workflow uses them in more detail.

Security

Bucket credentials are encrypted before storage and are only used within isolated runtime environments when Altertable needs to access the bucket.

See Encryption for platform-wide details.

Learn More

• Altertable Catalogs: Create managed catalogs backed by a bucket
• External Catalogs: Connect databases, warehouses, and file-backed catalogs
• Encryption: How Altertable protects credentials and stored data