Schema Validation

The API schema defines which API requests are valid based on several request properties like target endpoint, path or query variable format, and HTTP method.

Schema Validation allows you to check if incoming traffic complies with a previously supplied API schema. When you provide an API schema or select from a list of learned schema, API Shield creates rules for incoming traffic from the schema definitions. These rules define which traffic is allowed and which traffic gets logged or blocked.

Cloudflare has recently launched Schema Validation 2.0. For help configuring the previous version of Schema Validation for one or more hosts using the dashboard, refer to Configure Classic Schema Validation. You can make changes to your Classic Schema Validation settings but you cannot add any new schemas.

You can migrate to Schema Validation 2.0 manually by uploading your schemas to the new system, or you can wait for a future release where we will add an easy migrate option per-schema.

​​ Process

Endpoints must be added to Endpoint Management for Schema Validation to protect them. Uploading a schema will automatically add endpoints, or you can manually add them from API Discovery.

The API endpoint is the location where API calls or requests are fulfilled. API Shield defines endpoints as a host, method, and path tuple.

​​ Add validation by uploading a schema

1. Log in to the Cloudflare dashboard Open external link and select your account and domain.
2. Select Security > API Shield.
3. Go to Schema Validation and select Add validation.
4. Select your schema file for upload.
5. Observe the listed endpoints, their host, method, and path. Any new endpoints will automatically be added to Endpoint Management.
6. Choose an action for the non-compliant requests to your endpoints.
7. Select Add schema and endpoints.

​​ Add validation by applying a learned schema to a single endpoint

1. Log in to the Cloudflare dashboard Open external link and select your account and domain.
2. Select Security > API Shield.
3. Go to Schema Validation and filter by the learned schema available.
4. Select Apply learned schema.
5. Choose an action and select Apply schema.

​​ Add validation by applying a learned schema to an entire hostname

At this time, learned schemas will not overwrite customer-uploaded schemas. If an endpoint is covered by a customer-uploaded schema and also appears in a learned schema, the Changes field is set to Unaffected.

1. Log in to the Cloudflare dashboard Open external link and select your account and domain.
2. Select Security > API Shield.
3. Go to Schema Validation and select Add Validation.
4. Select Apply learned schema.
5. Choose a hostname and review the endpoints that will be protected by the learned schema.
6. (Optional) Change the action if a request does not match the schema.
7. Select Apply schema.

​​ Change the action of an entire schema

1. Log in to the Cloudflare dashboard Open external link and select your account and domain.
2. Select Security > API Shield.
3. Go to Schema Validation and select the schema in the Schema list.
4. Check the multi-select box to select the endpoints shown on the current page.
5. Choose Select all endpoints.
6. Select Change Action.
7. Choose an action from the dropdown menu.
8. Select Set action.

​​ Change the global default action of Schema Validation

Schema Validation’s default action is visible on the main Schema Validation page. This action applies to any endpoint with its action set to Default.

• Log action: logs events to Firewall Events.
• Block action: blocks requests that fail the schema for an endpoint and logs events to Firewall Events.
• None action: non-compliant requests are neither logged nor blocked.

To change the default action:

1. Log in to the Cloudflare dashboard Open external link and select your account and domain.
2. Go to Security > API Shield.
3. Select Schema Validation.
4. Under the default Log action, select Change.
5. Choose a new action from the dropdown menu.
6. Observe the current action and accept the change by selecting Change default action in the popup window.

Alternatively, you can modify the global action via Security > API Shield > Settings.

​​ Change the action of a single endpoint

You can change individual endpoint actions separately from the default action in Schema Validation.

This allows you to be stricter on blocking non-compliant requests on certain endpoints when the default action is Log. It can also be used to relax constraints on non-compliant requests on certain endpoints when the default action is set to Block. You may want to silence known false positives on an endpoint by setting the action to None.

To change the action on an individual endpoint:

1. Log in to the Cloudflare dashboard Open external link and select your account and domain.
2. Go to Security > API Shield.
3. Select Schema Validation and filter the selected endpoint.
4. Select the ellipses on the endpoint’s row.
5. Select Change Action.
6. Choose a new action from the dropdown menu and select Set action.

​​ Disable Schema Validation without changing actions

You can disable Schema Validation entirely for temporary troubleshooting. You can override all actions at once, preventing Schema Validation from taking any action while you complete your troubleshooting.

1. Log in to the Cloudflare dashboard Open external link and select your account and domain.
2. Select Security > API Shield.
3. Go to the Schema Validation settings.
4. Select Disable.

Your per-endpoint configurations will be saved when modifying the setting, so that you do not lose your configuration. To re-enable your configurations after troubleshooting, navigate back to the settings and select Enable.

​​ View active schemas

To view currently uploaded or learned schemas:

1. Log in to the Cloudflare dashboard Open external link and select your account and domain.
2. Select Security > API Shield.
3. Go to your Schema Validation settings.
4. View your schemas under Uploaded Schemas and Learned schemas.
5. Select Filter on the endpoints in either schema.

​​ Delete active schemas

Deleting the schema will remove validation from the currently associated endpoints, but it will not delete the endpoints from Endpoint Management.

To delete currently uploaded or learned schemas:

1. Log in to the Cloudflare dashboard Open external link and select your account and domain.
2. Select Security > API Shield.
3. Go to your Schema Validation settings.
4. View your schemas under Uploaded Schemas and Learned schemas.
5. Select the ellipses to access the menu and download or delete the listed schema.

​​ Specifications

Cloudlflare currently only accepts OpenAPI v3 schemas Open external link . The accepted file formats are YAML (.yml or .yaml file extension) and JSON (.json file extension).

OpenAPI schemas generated by different tooling may not be specific enough to import to Schema Validation. We recommend using a third-party tool such as Swagger Editor Open external link to ensure that schemas are compliant to the OpenAPI specification.

​​ Limitations

Currently, API Shield cannot validate some features of API schemas, including the following: all responses, external references, non-basic path templating, or unique items.

There is a limit of 1000 total operations for enabled schemas. We will raise this limit in the near future.

​​ Body inspection

API Shield has the ability to identify body specifications in uploaded schemas and validate the data of incoming API requests.

The supported content-type format is application/json. The code must validate that no other content media ranges are uploaded.

*/*, application/*, and application/json media-ranges are valid. We will also only accept the charset parameter with a static value of utf-8.

​​ Availability

Schema Validation is available for all API Shield customers.

Enterprise customers who have not purchased API Shield can preview API Shield as a non-contract service Open external link in the Cloudflare dashboard or by contacting your account team.