> For the complete documentation index, see [llms.txt](https://developer.xyxyx.pro/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://developer.xyxyx.pro/getting-started/authentication.md).

# Authentication

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Access to the Xyxyx API Testnet is limited to Xyxyx API Keys.
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The Xyxyx API pioneers a new, innovative approach to API authentication by leveraging blockchain technology via the EVM instead of traditional methods like the OAuth 2.0 protocol. Xyxyx's blockchain-based, dual-token method ensures permissionless, secure, and efficient access to the API.

 Xyxyx API authentication is achieved through two methods:

* [**Xyxyx API Keys**](/getting-started/xyxyx-api-keys.md)
* [**Xyxyx Issuer Nodes (XINs)**](https://docs.xyxyx.pro/protocol/xyxyx/xyxyx-issuer-nodes-xins)

The API authentication can occur based on three architectures:

1. **Node**

Users can authenticate via a node. This means `1` **Xyxyx API Key** or `1` **XIN** owned by an address.

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2. **Cluster**

Users can authenticate via a cluster. This means multiple Xyxyx API Keys or multiple XINs owned by an address.

e.g., `2` **Xyxyx API Keys** or `2` **XINs**

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3. **Composite**

Users can authenticate via a composite. This means a token composite between Xyxyx API Keys and XINs.

e.g., `1` **Xyxyx API Key** + `1` **XIN**

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Refer to the [Getting an API Key](/getting-started/quickstart.md) page to learn how to get an Xyxyx API or an XIN.

Refer to the [Rates & Limits](/getting-started/rates-and-limits.md) page to learn about rates and limits of Xyxyx API Keys and XINs.