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

# Network Transformers

> Customize network configuration before it's used throughout the SDK

Modify network properties (like RPC URLs, block explorers, or native currency) before they're used by the SDK. Set once during initialization, applies to all operations.

<Accordion title="New to web3?">
  **What is an RPC?** An RPC (remote procedure call) endpoint is the URL your app uses to read from and write to a blockchain (e.g. send transactions, read balances). The SDK needs at least one RPC URL per network.

  **Why set your own?** You might set custom RPC URLs for rate limits, reliability, or to use a provider you already use (e.g. Alchemy, Infura). If you don't set them, the SDK uses defaults from the Dynamic dashboard.

  **When can I skip this?** If you're fine with dashboard defaults and don't need to customize networks, you don't need to use network transformers. Only use this page when you want to override RPC URLs, block explorers, or other network data.
</Accordion>

## Prerequisites

Before this: create and initialize a Dynamic client (see [Creating a Dynamic Client](/javascript/reference/client/create-dynamic-client), [Initializing the Dynamic Client](/javascript/reference/client/initialize-dynamic-client)). You also need `@dynamic-labs-sdk/client` installed; RPC provider API keys are optional.

## Quick Start

```javascript theme={"system"}
import { createDynamicClient } from '@dynamic-labs-sdk/client';

const dynamicClient = createDynamicClient({
  environmentId: 'YOUR_ENVIRONMENT_ID',
  transformers: {
    networkData: (network) => {
      if (network.networkId === '1') {
        return {
          ...network,
          rpcUrls: {
            http: ['https://eth-mainnet.g.alchemy.com/v2/YOUR-KEY'],
          },
        };
      }
      return network;
    },
  },
});
```

## Common Patterns

**Multiple networks:**

```javascript theme={"system"}
const RPC_URLS = {
  '1': process.env.ETHEREUM_RPC_URL,
  '137': process.env.POLYGON_RPC_URL,
  '8453': process.env.BASE_RPC_URL,
};

transformers: {
  networkData: (network) => {
    const url = RPC_URLS[network.networkId];
    return url ? { ...network, rpcUrls: { http: [url] } } : network;
  },
}
```

**Fallback URLs:**

```javascript theme={"system"}
transformers: {
  networkData: (network) => ({
    ...network,
    rpcUrls: {
      http: [`https://primary.com/${process.env.KEY}`, ...network.rpcUrls.http],
    },
  }),
}
```

**Environment-based:**

```javascript theme={"system"}
const getRpcUrl = (network) => {
  if (process.env.NODE_ENV === 'development') return 'http://localhost:8545';
  if (process.env.NODE_ENV === 'staging') return 'https://sepolia-rpc.com';
  return `https://mainnet.g.alchemy.com/v2/${process.env.ALCHEMY_KEY}`;
};

transformers: {
  networkData: (network) => ({
    ...network,
    rpcUrls: { http: [getRpcUrl(network)] },
  }),
}
```

## NetworkData shape

The `network` object passed to your transformer has the following fields:

| Field               | Type                                                 | Description                                                              |
| ------------------- | ---------------------------------------------------- | ------------------------------------------------------------------------ |
| `networkId`         | `string`                                             | Unique identifier for the network (chain ID for EVM, cluster for Solana) |
| `name`              | `string`                                             | Human-readable network name                                              |
| `rpcUrls`           | `{ http: string[] }`                                 | List of RPC endpoints for the network                                    |
| `nativeCurrency`    | `{ name: string, symbol: string, decimals: number }` | Native token details                                                     |
| `blockExplorerUrls` | `string[]`                                           | Block explorer URLs                                                      |
| `chainName`         | `string`                                             | The blockchain family (e.g., `'ETH'`, `'SOL'`, `'SUI'`)                  |

You can modify any of these fields. Always return the full object — spread the original and override only what you need.

## Network IDs

EVM networks use chain IDs: `'1'` (Ethereum), `'137'` (Polygon), `'8453'` (Base), `'42161'` (Arbitrum), `'10'` (Optimism), `'11155111'` (Sepolia)

Solana networks use cluster names: `'mainnet-beta'`, `'devnet'`, `'testnet'`

The transformer applies to all chains — EVM, Solana, Sui, and others enabled in your project.

## Provider Examples

**Alchemy:**

```javascript theme={"system"}
const KEY = process.env.ALCHEMY_KEY;
const RPC_URLS = {
  '1': `https://eth-mainnet.g.alchemy.com/v2/${KEY}`,
  '137': `https://polygon-mainnet.g.alchemy.com/v2/${KEY}`,
};
```

**Infura:**

```javascript theme={"system"}
const KEY = process.env.INFURA_KEY;
const RPC_URLS = {
  '1': `https://mainnet.infura.io/v3/${KEY}`,
  '137': `https://polygon-mainnet.infura.io/v3/${KEY}`,
};
```

## Rules

* Always return valid `NetworkData` structure
* Use environment variables for API keys
* Keep transformers synchronous (no async/await)
* Transformers are called once during initialization

## React

Network transformers are configured at client creation time, so they live in the same module-level file as your `createDynamicClient` call. No React-specific wiring needed — the transformer runs once during initialization before any component renders.

## Related

* [createDynamicClient](/javascript/reference/client/create-dynamic-client)