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".

Because a bucket name can appear in a DNS record as part of a CNAME or A redirect, your bucket name should conform to standard DNS naming conventions. This means that you should not use underscores (_) or have a period next to another period or dash. For example, ".." or "-." or ".-" are not valid in DNS names.

Bucket name considerations

Bucket names reside in a single Cloud Storage namespace. This means that:

  • Every bucket name must be unique.
  • Bucket names are publicly visible.

If you try to create a bucket with a name that already belongs to an existing bucket, Cloud Storage responds with an error message. However, once you delete a bucket, you or another user 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, 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.

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.

See also the Naming Best Practices section, which includes recommendations about excluding proprietary information from bucket names.

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