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Object Storage Service:Bucket naming conventions

Last Updated:Mar 20, 2026

A bucket is a container for storing objects in Object Storage Service (OSS). Each object belongs to exactly one bucket. When you create a bucket, you set its region, access control list (ACL), and storage class.

Bucket names are permanent — you cannot rename a bucket after it is created. Each Alibaba Cloud account can create up to 100 buckets per region.

Naming rules

OSS enforces the following rules for bucket names:

RuleRequirement
Globally uniqueThe name must be globally unique in OSS.
Allowed charactersLowercase letters, digits, and hyphens (-) only.
Start and endMust begin and end with a lowercase letter or a digit.
Length3 to 63 characters.

Examples

Valid names:

  • examplebucket1

  • test-bucket-2021

  • aliyun-oss-bucket

Invalid names:

NameReason
Examplebucket1Contains uppercase letters
test_bucket_2021Contains underscores (_)
aliyun-oss-bucket-Ends with a hyphen (-)