> For the complete documentation index, see [llms.txt](https://docs.parallels.com/landing/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.parallels.com/landing/ras-client-integration-guide/ras-web-client-api.md).

# RAS Web Client API

This chapter describes how to integrate a third-party web portal with the RAS Web Client ([User Portal](https://docs.parallels.com/landing/ras-user-portal-guide/)) to authenticate users and launch published resources.

There are two integration methods:

* **Authentication Handoff API** (current). Your integration POSTs a JSON payload with the user's credentials to the RAS Secure Gateway, which responds with a redirect to the User Portal. This is the supported method for all new integrations. See [**Authentication Handoff API**](/landing/ras-client-integration-guide/ras-web-client-api/authentication-handoff-api.md).
* **Legacy Web Client API** (deprecated) launch data is passed through a JavaScript payload URL (?appinfo=...). This method is deprecated and is disabled by default starting with Parallels RAS 21.2.

{% hint style="warning" %}
**Attention**: The legacy Web Client API (appinfo payload) is deprecated for security reasons. When you upgrade to Parallels RAS 21.2 or later, it is disabled by default. Existing integrations must migrate to the Authentication Handoff API. See [**Migrating from the Legacy Web Client API**](/landing/ras-client-integration-guide/ras-web-client-api/migrating-from-the-legacy-web-client-api.md).
{% endhint %}


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