Bucket naming guidelines

This page outlines the naming guidelines you should follow when creating buckets in Cloud Storage. To learn how to create a bucket, see the Creating storage buckets guide.

Bucket name requirements

Your bucket names must meet the following requirements:

  • Bucket names must contain only lowercase letters, numbers, dashes (-), underscores (_), and dots (.). Spaces are not allowed. Names containing dots require verification.
  • Bucket names must start and end with a number or letter.
  • Bucket names must contain 3-63 characters. Names containing dots can contain up to 222 characters, but each dot-separated component can be no longer than 63 characters.
  • Bucket names cannot be represented as an IP address in dotted-decimal notation (for example, 192.168.5.4).
  • Bucket names cannot begin with the "goog" prefix.
  • Bucket names cannot contain "google" or close misspellings, such as "g00gle".

Bucket name considerations

  • Bucket names reside in a single namespace that is shared by all Cloud Storage users.

    This means that:

    • Every bucket name must be globally unique.

      If you try to create a bucket with a name that already belongs to an existing bucket, such as example-bucket, Cloud Storage responds with an error message.

    • Bucket names are publicly visible.

      Don't use user IDs, email addresses, project names, project numbers, or any personally identifiable information (PII) in bucket names because anyone can probe for the existence of a bucket.

  • A bucket name can only be assigned during creation.

    You cannot change the name of an existing bucket. Instead, you should create a new bucket with the desired name and move the contents from the old bucket to the new bucket. See Moving and Renaming Buckets for a step-by-step guide.

  • Once you delete a bucket, anyone can reuse its name for a new bucket.

    The time it takes a deleted bucket's name to become available again is typically on the order of seconds; however, keep in mind the following:

    • If the new bucket is created in a different location and within 10 minutes of the old bucket's deletion, requests made to the new bucket during this 10 minute time frame might fail with a 404-Bucket Not Found error.

    • If your requests go through the XML API, attempts to create a bucket that reuses a name in a new location might fail with a 404-Bucket Not Found error for up to 10 minutes after the old bucket's deletion.

    • If you delete the project that contains the bucket, which effectively deletes the bucket as well, the bucket name may not be released for weeks or longer.

  • You can use a bucket name in a DNS record as part of a CNAME or A redirect.

    In order to do so, your bucket name should conform to standard DNS naming conventions. This means that your bucket name should not use underscores (_) or have a period next to another period or dash. For example, ".." is not valid within DNS names and neither is "-." or ".-".

Example bucket names

The following are examples of valid bucket names:

  • my-travel-maps
  • 0f75d593-8e7b-4418-a5ba-cb2970f0b91e
  • test.example.com (Requires verification of ownership for example.com)

The following are examples of invalid bucket names:

  • My-Travel-Maps (contains uppercase letters)
  • my_google_bucket (contains "google")
  • test bucket (contains a space)

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