# Approval Rule and Approval Flow Messages

Messages that represent a change or an action performed on an Approval Rule or Approval Flow.

Messages are available in a variety of [Message Types](/api/projects/messages.md#message-types) specific to a resource. Common fields across all Message Types are represented by a base resource, [Message](/search.md?urn=ctp:api:type:Message).

You can access Messages either by querying the [Messages API](/api/projects/messages.md), or by subscribing to them with a [Subscription](/api/projects/subscriptions.md). To query Messages using the API, you must [enable the feature](/api/projects/messages.md#enable-querying-messages-via-the-api) first.

### Approval Rule Messages

Messages that represent a change or an action performed on an [Approval Rule](/api/projects/approval-rules.md).

#### Approval Rule Created

[type definition](/search.md?urn=ctp:api:type:ApprovalRuleCreatedMessage).

#### Approval Rule Status Set

[type definition](/search.md?urn=ctp:api:type:ApprovalRuleStatusSetMessage).

#### Approval Rule Name Set

[type definition](/search.md?urn=ctp:api:type:ApprovalRuleNameSetMessage).

#### Approval Rule Description Set

[type definition](/search.md?urn=ctp:api:type:ApprovalRuleDescriptionSetMessage).

#### Approval Rule Key Set

[type definition](/search.md?urn=ctp:api:type:ApprovalRuleKeySetMessage).

#### Approval Rule Predicate Set

[type definition](/search.md?urn=ctp:api:type:ApprovalRulePredicateSetMessage).

#### Approval Rule Approvers Set

[type definition](/search.md?urn=ctp:api:type:ApprovalRuleApproversSetMessage).

#### Approval Rule Requesters Set

[type definition](/search.md?urn=ctp:api:type:ApprovalRuleRequestersSetMessage).

### Approval Flow Messages

Messages that represent a change or an action performed on an [Approval Flow](/api/projects/approval-flows.md).

#### Approval Flow Created

[type definition](/search.md?urn=ctp:api:type:ApprovalFlowCreatedMessage).

#### Approval Flow Approved

[type definition](/search.md?urn=ctp:api:type:ApprovalFlowApprovedMessage).

#### Approval Flow Rejected

[type definition](/search.md?urn=ctp:api:type:ApprovalFlowRejectedMessage).

#### Approval Flow Completed

[type definition](/search.md?urn=ctp:api:type:ApprovalFlowCompletedMessage).

## Related pages

- [Area overview page with navigation](/api.md)
- [Next page: Business Unit and Associate Role Messages](/api/projects/messages/business-unit-associate-role-messages.md)
- [Search documentation and API specs](/search.md)