# Sandbox API key

> 👍
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> **Availability:** Enterprise plan, Business plan

We don't charge for making API calls with the Sandbox key. Developers can use the Sandbox key to evaluate our API and build a proof of concept.

# Limitations

* API calls with the Sandbox key have a limit of 10 requests per minute, per endpoint.
* Generated PDFs have watermarks and created documents have the "\[DEV]" prefix by default.
* You can [send documents](https://developers.pandadoc.com/reference/send-document) only to emails within your domain - we compare domains of sender's and recipient's emails.

Once you get a Production Key enabled, the rate limits for Sandbox are increased so you can use it for continuous testing.