Tagging Your Amazon CloudWatch Events Resources

Note Amazon EventBridge is the preferred way to manage your events. CloudWatch Events and EventBridge are the same underlying service and API, but EventBridge provides more features. Changes you make in either CloudWatch or EventBridge will appear in each console. For more information, see Amazon EventBridge.

A tag is a custom attribute label that you assign or that AWS assigns to an AWS resource. Each tag has two parts:

• A tag key (for example, CostCenter, Environment, or Project). Tag keys are case sensitive.

• An optional field known as a tag value (for example, 111122223333 or Production). Omitting the tag value is the same as using an empty string. Like tag keys, tag values are case sensitive.

Tags help you do the following:

• Identify and organize your AWS resources. Many AWS services support tagging, so you can assign the same tag to resources from different services to indicate that the resources are related. For example, you could assign the same tag to a CloudWatch Events rule that you assign to an EC2 instance.

• Track your AWS costs. You activate these tags on the AWS Billing and Cost Management dashboard. AWS uses the tags to categorize your costs and deliver a monthly cost allocation report to you. For more information, see Use Cost Allocation Tags in the AWS Billing User Guide.

The following sections provide more information about tags for CloudWatch Events.

Supported Resources in CloudWatch Events

The following resources in CloudWatch Events support tagging:

• Rules

For information about adding and managing tags, see Managing Tags.

Managing Tags

Tags consist of the Key and Value properties on a resource. You can use the CloudWatch console, the AWS CLI, or the CloudWatch Events API to add, edit, or delete the values for these properties. For information about working with tags, see the following:

• TagResource, UntagResource, and ListTagsForResource in the Amazon CloudWatch Events API Reference

• tag-resource, untag-resource, and list-tags-for-resource in the Amazon CloudWatch CLI Reference

• Working with Tag Editor in the Resource Groups User Guide

Tag Naming and Usage Conventions

The following basic naming and usage conventions apply to using tags with CloudWatch Events resources:

• Each resource can have a maximum of 50 tags.

• For each resource, each tag key must be unique, and each tag key can have only one value.

• The maximum tag key length is 128 Unicode characters in UTF-8.

• The maximum tag value length is 256 Unicode characters in UTF-8.

• Allowed characters are letters, numbers, spaces representable in UTF-8, and the following characters: . : + = @ _ / - (hyphen).

• Tag keys and values are case sensitive. As a best practice, decide on a strategy for capitalizing tags and consistently implement that strategy across all resource types. For example, decide whether to use Costcenter, costcenter, or CostCenter and use the same convention for all tags. Avoid using similar tags with inconsistent case treatment.

• The aws: prefix is prohibited for tags because it's reserved for AWS use. You can't edit or delete tag keys or values with this prefix. Tags with this prefix don't count against your tags per resource quota.