# Setup Provider

City uses a **provider-based KYC model**. The `CityKycClient` defines the verification interface, while concrete providers handle the underlying API calls. This means you can swap or extend providers without changing your application code.

`SumsubKycProvider` is the current default provider.

```
import { CityKycClient, SumsubKycProvider } from "@cityprotocol/core";

const provider = new SumsubKycProvider({
  appToken: process.env.SUMSUB_APP_TOKEN!,
  secretKey: process.env.SUMSUB_SECRET_KEY!,
});

const kycClient = new CityKycClient({ provider });
```


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