Resource Tagging

API limits

Limit	Value	Error code
Maximum tags per account	100,000	N/A
Maximum tag key length	256 characters	1011
Maximum tag value length	1,024 characters	1012
Maximum tag filters per query	20	1010
Maximum OR values per filter	10	1013
Results per page	100 (fixed)	N/A

Access service tokens have resource-specific limits: up to five tags per token, with keys and values each limited to 256 characters.

When a limit is exceeded, the API returns 400 Bad Request with the corresponding error code.

During the beta, each account is limited to 10,000 total tags. If you need a higher limit, contact Cloudflare support.

Case sensitivity

Tag keys and values are case-sensitive. Environment, environment, and ENVIRONMENT are treated as three distinct keys. Be consistent with casing conventions across your organization to avoid duplicate keys.

Tag key validation

Tag keys must follow these character rules:

Allowed

• Unicode letters (any language)
• Unicode digits (0-9)
• Underscores ( _)
• Periods ( .)
• Hyphens ( -)

Not allowed

• Empty strings
• Spaces
• Special characters (except _, ., -)

Examples

Key	Valid	Reason
environment	Yes	Letters only
team_name	Yes	Underscore
cost-center	Yes	Hyphen
owner.email	Yes	Period
env123	Yes	Letters and digits
env name	No	Contains space
team@work	No	Special character @
(empty)	No	Empty string

Invalid tag keys return 400 Bad Request with error code 1014.

Pagination

List endpoints use cursor-based pagination with a fixed page size of 100. The page size is not configurable.

Paginated endpoints:

• GET /accounts/{account_id}/tags/keys
• GET /accounts/{account_id}/tags/resources
• GET /accounts/{account_id}/tags/values/{tag_key}

Refer to Filter resources by tag for pagination examples.