---
category: [Administration & Integrations, Administration & Integrations/Workday API, Platform and Product Extensions, Platform and Product Extensions/Integration]
keyword: [Extend, Integrate, REST API]
nav: wcp_docs
parent_url: /wcp_docs/
title: >- 
  FAQ: REST Metadata API
layout: subsection
---

<a id="section_qbf_41d_rsb"></a>
-   [What security access model does the Metadata API use?](/wcp_docs/eyc1645578208431.html#dlentry_security)
-   [In what format is the metadata response?](/wcp_docs/eyc1645578208431.html#dlentry_format)
-   [How do the metadata tags relate to the standard API call? What does it mean that a field is hidden or not?](/wcp_docs/eyc1645578208431.html#dlentry_metadata_tags)
-   [Does “readOnly” mean that a standard REST “PUT” method can't write data to that field?](/wcp_docs/eyc1645578208431.html#dlentry_readOnly)
-   [Can I use Metadata API calls with RaaS?](/wcp_docs/eyc1645578208431.html#dlentry_raas)
-   [How does it work if no version is specified?](/wcp_docs/eyc1645578208431.html#dlentry_noVersion)
-   [Is the wd-metadata-api-version header backwards compatible?](/wcp_docs/eyc1645578208431.html#dlentry_backwardsCompatible)


<a id="section_N1007B_N1004A_N10001"></a>
-   <a id="dlentry_security"></a><b>What security access model does the Metadata API use?</b>

    The Workday REST Metadata API uses the same security access model as a standard Workday REST API to get a metadata response. If the user has the appropriate security privileges to call an API in the standard way, then they can also call that same API with the `wd-metadata-api-version` header and receive a metadata response.

-   <a id="dlentry_format"></a><b>In what format is the metadata response?</b>

    The metadata <b>v1</b> response is an extension of the OpenAPI 2.0 Specification.

    The metadata <b>v2</b> response follows the OpenAPI 3.0.1 Specification.

-   <a id="dlentry_metadata_tags"></a><b>How do the metadata tags relate to the standard API call? What does it mean that a field is hidden or not?</b>

    The Metadata API allows the calling user to discern which fields the standard API response would return. The Metadata API response depends on the configured conditions or the current security permissions of the user.

    If a field has a value for `hidden`, then the response depends on what type of object you're calling and the conditions or security configuration related to it. If the standard REST response would hide the field due to insufficient user permissions, then the metadata response for that user indicates the field as hidden. Example:

    ```
    "hidden":"true"
    ```

    The corresponding standard REST response (without the Metadata API header) doesn't return the value of that field from the calling user.

    Conversely, assume that the calling user has the requisite security or meets the required conditions to view the value of that field. If the standard REST response would return the field to the user, then the metadata response for that user indicates the field as not hidden. Example:

    ```
    "hidden":"false"
    ```

    The corresponding standard REST response (without the Metadata API header) returns the value of that field to the calling user.

    Example: A REST API returns fields based on whether the calling user is a salaried worker or a temporary worker. Those fields would include the `hidden` property in the Metadata API response.

    In this example, if the processing user is a salaried worker, the Metadata API would return `"hidden" : "false"` for those fields. However, if the processing user is a temporary worker, then the Metadata API would return `"hidden" : "true"` for the same fields. The Metadata API returns the field with the `hidden` property for the temporary worker, but the standard REST response doesn't return the field.

-   <a id="dlentry_readOnly"></a><b>Does “readOnly” mean that a standard REST “PUT” method can't write data to that field?</b>

    Yes. If a field is readOnly, data can't be written with a PUT, POST, or PATCH HTTP method.

-   <a id="dlentry_raas"></a><b>Can I use Metadata API calls with RaaS?</b>

    No. The Metadata API isn't supported with RaaS requests.

-   <a id="dlentry_noVersion"></a><b>How does it work if no version is specified?</b>

    If you specify the `wd-metadata-api-version` header with your REST API request, you must specify the version as the header value. See [Concept: Validate Only Mode for REST APIs](/wcp_docs/rni1611281077170.html) for the list of versions.

    If you don't specify the `wd-metadata-api-version` header, the REST API request returns the normal response and doesn't return the metadata.

-   <a id="dlentry_backwardsCompatible"></a><b>Is the wd-metadata-api-version header backwards compatible?</b>

    If you continue to use Metadata API v1 by setting `wd-metadata-api-version` to v1, your existing integrations continue to receive the OpenAPI 2.0 response format with a single default representation.



### Related Information

[Concept: REST Metadata API Header](/wcp_docs/pyd1580334491723.html)