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

# getDefaultEvmRpcUrls

```ts theme={null}
function getDefaultEvmRpcUrls(): Promise<Record<string, {
  rpcUrl: string;
}>>;
```

Defined in: [constants.ts:94](https://github.com/coinbase/cdp-sdk/blob/a1195adcfa5a93627bd3cb79831b188cc13073a1/typescript/packages/cdp-sdk/src/x402/constants.ts#L94)

Resolves the default EVM RPC URLs used for x402 payment signing, keyed by
CAIP-2 network identifier.

Only Base and Base Sepolia get a default: both are backed by the CDP
project's own authenticated node endpoint (via getBaseNodeRpcUrl),
so no shared public infrastructure sits on the payment-signing path and no
extra configuration is required to use them.

All other networks (Polygon, Arbitrum, World, etc.) have no default RPC.
RPC URLs are optional for core payload signing on those networks — they're
only needed to backfill optional extension capabilities (for example,
`eip2612` gas-sponsoring enrichment) — so callers that need one must supply
it explicitly via the `rpcUrls` config option or `CDP_X402_RPC_URLS`
environment variable.

## Returns

`Promise`\<`Record`\<`string`, \{
`rpcUrl`: `string`;
}>>

CAIP-2 keyed RPC configuration map containing only the networks
that resolved successfully.