> ## Documentation Index
> Fetch the complete documentation index at: https://engineering.unkey.com/llms.txt
> Use this file to discover all available pages before exploring further.

# OpenAPI validation

> OpenAPI request validation

OpenAPI validation rejects requests that do not conform to an OpenAPI 3.0 or 3.1 specification before they reach the upstream instance. The policy engine compiles the spec into a validator and validates each matched request against it.

## Fields

<ResponseField name="spec_yaml" type="bytes">
  The OpenAPI specification as raw YAML bytes. Frontline parses the spec at evaluation time and validates the request path, method, parameters, and request body against it.
</ResponseField>

## Example

```json theme={"theme":"kanagawa-wave"}
{
  "policies": [
    {
      "id": "schema-validation",
      "name": "Validate requests against OpenAPI spec",
      "enabled": true,
      "match": [
        { "path": { "path": { "prefix": "/v1/" } } }
      ],
      "openapi": {
        "spec_yaml": "openapi: '3.0.3'\ninfo:\n  title: My API\n  version: '1.0'\npaths:\n  /v1/keys:\n    post:\n      requestBody:\n        required: true\n        content:\n          application/json:\n            schema:\n              type: object\n              required: [name]\n              properties:\n                name:\n                  type: string\n"
      }
    }
  ]
}
```