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

# Configuring Hashio RPC endpoints

How to configure a JSON-RPC endpoint that enables communication between EVM-compatible developer tools using Hashio.

Hashio is a public RPC endpoint hosted by [Hashgraph](https://www.hashgraph.com/) that runs an instance of the [Hiero JSON-RPC Relay](https://github.com/hiero-ledger/hiero-json-rpc-relay). As a *public* endpoint, it:

* Is free to use
* Does not have any sign-up requirements
* Has significantly restrictive rate limits

While this combination may be considered less reliable, it offers the highest levels of ease of use among RPC endpoints.

To connect to the Hedera networks via Hashio, simply use one of these URLs when initializing the wallet or web3 provider instance:

<CodeGroup>
  ```text Mainnet theme={null}
  https://mainnet.hashio.io/api
  ```

  ```text Testnet theme={null}
  https://testnet.hashio.io/api
  ```

  ```text Previewnet theme={null}
  https://previewnet.hashio.io/api
  ```
</CodeGroup>

The corresponding chain IDs are:

| Network        | Chain ID (decimal) | Chain ID (hex) |
| -------------- | :----------------: | :------------: |
| **Mainnet**    |        `295`       |     `0x127`    |
| **Testnet**    |        `296`       |     `0x128`    |
| **Previewnet** |        `297`       |     `0x129`    |

No further settings or configurations are needed!

<Warning>
  **Please note**: Hashio is for development and testing purposes only. Production use cases are strongly encouraged to use [commercial-grade JSON-RPC relays](/evm/development/json-rpc#community-hosted-json-rpc-relays) or host their own instance of the [Hiero JSON-RPC Relay](https://github.com/hiero-ledger/hiero-json-rpc-relay).
</Warning>

## Additional resources

* [Hiero JSON-RPC Relay repository](https://github.com/hiero-ledger/hiero-json-rpc-relay)
* [JSON-RPC Relay overview](/evm/development/json-rpc)
* [How to connect MetaMask to Hedera](/evm/tutorials/beginner/connect-metamask)
* [Add Hedera to MetaMask](/evm/quickstart/setup-metamask)

***

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