> ## Documentation Index
> Fetch the complete documentation index at: https://docs.reown.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Universal Provider

Universal Provider is a multi-chain provider for WalletConnect v2 protocol.

<Info>
  Find more about different supported chains [here](../../cloud/chains/overview.md).
</Info>

## Installation

<CodeGroup>
  ```bash npm theme={null}
  npm install @walletconnect/universal-provider
  ```

  ```bash Yarn theme={null}
  yarn add @walletconnect/universal-provider
  ```

  ```bash Bun theme={null}
  bun add @walletconnect/universal-provider
  ```

  ```bash pnpm theme={null}
  pnpm add @walletconnect/universal-provider
  ```
</CodeGroup>

## Usage

```typescript theme={null}
import UniversalProvider from "@walletconnect/universal-provider";

//  Initialize the provider
const provider = await UniversalProvider.init({
  projectId: "YOUR_PROJECT_ID",
  metadata: {
    name: "React App",
    description: "React App for WalletConnect",
    url: "https://walletconnect.com/",
    icons: ["https://avatars.githubusercontent.com/u/37784886"],
  },
  client: undefined, // optional instance of @walletconnect/sign-client
});

//  create sub providers for each namespace/chain
await provider.connect({
  optionalNamespaces: {
    eip155: {
      methods: [
        "eth_sendTransaction",
        "eth_signTransaction",
        "eth_sign",
        "personal_sign",
        "eth_signTypedData",
      ],
      chains: ["eip155:80001"],
      events: ["chainChanged", "accountsChanged"],
      rpcMap: {
        80001:
          "https://rpc.walletconnect.com?chainId=eip155:80001&projectId=<your walletconnect project id>",
      },
    },
  },
  pairingTopic: "<123...topic>", // optional topic to connect to
  skipPairing: false, // optional to skip pairing ( later it can be resumed by invoking .pair())
});
```

## Events

```typescript theme={null}
// Subscribe for pairing URI
provider.on("display_uri", (uri) => {
  console.log("display_uri", uri);
});

// Subscribe to session ping
provider.on("session_ping", ({ id, topic }) => {
  console.log("session_ping", id, topic);
});

// Subscribe to session event
provider.on("session_event", ({ event, chainId }) => {
  console.log("session_event", event, chainId);
});

// Subscribe to session update
provider.on("session_update", ({ topic, params }) => {
  console.log("session_update", topic, params);
});

// Subscribe to session delete
provider.on("session_delete", ({ id, topic }) => {
  console.log("session_delete", id, topic);
});
```

## Provider Methods

```typescript theme={null}
interface RequestArguments {
  method: string;
  params?: any[] | undefined;
}

// Send JSON RPC requests

/**
 * @param payload
 * @param chain - optionally specify which chain should handle this request
 * in the format `<namespace>:<chainId>` e.g. `eip155:1`
 */
const result = await provider.request(payload: RequestArguments, chain: string | undefined);
```

## Chain switching

`DefaultChain` is the current chain that the provider will target for the next requested transaction.

```typescript theme={null}
// set the default chain to 56
provider.setDefaultChain(`eip155:56`, rpcUrl?: string | undefined);
```

## Session data

Once a wallet is connected you can find the session data in the `provider.session` object.

The session object includes the following properties, *among others*:

* **namespaces**: `session.namespaces` is an object that contains the approved session data.

<Warning>
  Note that the `chains` object is an optional parameter and may be undefined. Therefore, we encourage apps to obtain the approved chains from the `session.accounts` object instead.
</Warning>

```ts theme={null}
interface Namespaces {
  chains?: string[];
  accounts: string[];
  methods: string[];
  events: string[];
}
```

* **requiredNamespaces, optionalNamespaces & sessionProperties**: These objects contain the namespaces and properties proposed for the session.
* **peer**: The `session.peer.metadata` object contains the metadata of the connected wallet.

```ts theme={null}
interface Metadata {
  name: string;
  description: string;
  url: string;
  icons: string[];
  verifyUrl?: string;
  redirect?: {
    native?: string;
    universal?: string;
  };
}
```

Find the complete type definition of the `session` object [here](https://github.com/WalletConnect/walletconnect-monorepo/blob/022e4d492c9862ab9b17c1a7b12884bdcd992ae4/packages/types/src/sign-client/session.ts#L25).