# Credits

It is possible for users to subscribe to a credit-based API Key system: each request consumes a pre-definied amount of credits from your balance. This is the default model for users that subscribe to a free trial key.

For users with API credits, the credit spend per request is summarized in the below table:

<table data-full-width="true"><thead><tr><th width="253">Request</th><th width="230">Response status</th><th width="542">Description</th><th data-type="number">Cost (credits per request)</th></tr></thead><tbody><tr><td><code>predictAddressSingle</code></td><td><code>success</code></td><td>The API returned a successful response on a valid address</td><td>5</td></tr><tr><td><code>predictAddressSingle</code></td><td><code>warning: Address belongs to a smart contract</code></td><td>The requested address belongs to a smart contract which is out of the scope of analysis of the model</td><td>2</td></tr><tr><td><code>predictAddressSingle</code></td><td><code>warning: Address has no activity</code></td><td>The requested address has no activity on Ethereum: either it doesn't exist or its activity is only on other chains. Support for additional chains will be added over time.</td><td>1</td></tr><tr><td><code>predictAddressSingle</code></td><td><code>error</code></td><td>There is an error in the headers or payload (user side) or internal error preventing the API from returning a valid response</td><td>0</td></tr></tbody></table>
