# Create a Card Client

### Supported Providers

Card issuance and lifecycle is provider-backed, but integrators build against the stable City surface. The SDK follows a dependency-injection pattern: you instantiate a provider, then pass it into `CityCardClient`.

Supported providers include `ReapCardProvider`, `InterlaceCardProvider`, and `URCardProvider`. Each provider encapsulates its own authentication scheme, endpoint routing, and payload normalization so that the methods exposed on `CityCardClient` remain identical regardless of which provider is active.

***

### Create A Card Client

The `CityCardClient` is your primary interface for all card operations. It expects a configured provider instance.

```
import { CityCardClient, ReapCardProvider } from "@cityprotocol/core";

const provider = new ReapCardProvider({
  apiKey: process.env.REAP_API_KEY!,
});

const cardClient = new CityCardClient({ provider });
```

Swapping to a different provider requires only changing the provider constructor — every downstream call through `cardClient` stays the same.

```
import { CityCardClient, InterlaceCardProvider } from "@cityprotocol/core";

const provider = new InterlaceCardProvider({
  apiKey: process.env.INTERLACE_API_KEY!,
});

const cardClient = new CityCardClient({ provider });
```


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