# Configuring ENSIndexer

:::danger[Custom RPC Configuration Required]
**ENSIndexer requires private RPC endpoints.** Public (rate limited) RPC endpoints will not provide acceptable performance.

You must configure private (paid) RPC services from providers like Alchemy, QuickNode, drpc.org, or Infura or host your own RPC service that can handle high-volume requests.
:::

:::caution[Performance Tip: ENSRainbow Server]
Warning: Configuring ENSIndexer to use the public ENSRainbow server (`https://api.ensrainbow.io`) will significantly slow down indexing.
For optimal indexing performance, always colocate ENSIndexer and ENSRainbow. For example, if you are running ENSIndexer locally, you should also run a local instance of ENSRainbow and set `ENSRAINBOW_URL` to your local ENSRainbow server.
:::
ENSIndexer's behavior can be configured through environment variables. Copy `.env.local.example` to `.env.local` and configure all required values.

```bash
// .env.local.example
envExample
```

[.env.local.example](https://github.com/namehash/ensnode/blob/main/apps/ensindexer/.env.local.example)