> For the complete documentation index, see [llms.txt](https://developers.make.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://developers.make.com/custom-apps-documentation/best-practices/connections.md).

# Connections

Every connection should have a way to check if the used API key (token) is valid (a validation endpoint).

This means that each connection should have a part that uses the API key (token) against an endpoint that requires **only** the API key to run. For example, a user info endpoint, or any endpoint that is used to list data.

The validation endpoint is located:

* OAuth1 and OAuth2 - in the `info` directive
* API key, basic auth, digest auth, other - in the `url` in the Communication tab

{% hint style="info" %}
There are APIs that don't have a validation endpoint. In this case, it is recommended to call an endpoint that will work in every case and, if possible, will return the account's data, e. g. an endpoint `/about` or `/me`, etc.
{% endhint %}

{% tabs %}
{% tab title="Correct API Key" %}

<div align="left"><figure><img src="/files/siZtlOemAoj8DL9XOFmw" alt="" width="563"><figcaption></figcaption></figure></div>

{% hint style="info" %}
The API key is checked against the `/whoami` endpoint. If the API key is incorrect, this returns an error and the connection won't be created.
{% endhint %}
{% endtab %}
{% endtabs %}


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