> For the complete documentation index, see [llms.txt](https://doc.bunq.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://doc.bunq.com/basics/authentication.md).

# Authentication

When integrating with the bunq API, you can authenticate using either an **API key** or **OAuth**, depending on your use case. **API keys** provide a straightforward way to authenticate, making them ideal for server-to-server communication and automated scripts. They offer fast access but come with security risks if exposed, as they grant broad permissions. **OAuth**, on the other hand, is designed for third-party applications that need user-specific access. It allows fine-grained permissions and secure authentication without sharing credentials but requires a more complex authorization flow. Choose the method that best fits your needs:

{% hint style="info" %}
OAuth is the obligatory authentication method for public projects whereas using API keys is allowed as long as only you have access to your application.
{% endhint %}

{% content-ref url="/pages/sY7NIUhQd0YOhIITR7nE" %}
[API Keys](/basics/authentication/api-keys.md)
{% endcontent-ref %}

{% content-ref url="/pages/nQpuM79hqrXIE9iNgCIm" %}
[OAuth](/basics/authentication/oauth.md)
{% endcontent-ref %}


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