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

# Adding a custom RPC endpoint to Rabby

> Point Rabby at a Chainstack RPC endpoint. Use Modify RPC URL to replace the node Rabby uses on a chain it already supports, or Add Custom Network to add a chain Rabby doesn't support yet.

**TLDR:**

* Rabby has two separate flows — **Modify RPC URL** replaces the node Rabby uses on a chain it already supports, and **Add Custom Network** adds a chain Rabby doesn't support yet.
* For a supported chain, go to **Settings** > **Modify RPC URL** and paste your Chainstack HTTPS endpoint.
* A custom RPC replaces Rabby's own node for that chain. Delete the entry to go back to Rabby's node.

<Card title="Create a node on Chainstack" href="https://console.chainstack.com/" icon="server" horizontal>
  Deploy an RPC node across 70+ protocols in minutes, then copy its HTTPS endpoint into Rabby.
</Card>

## Which flow you need

Rabby keeps the two cases apart, and picking the wrong one either duplicates a chain you already have or leaves your endpoint unused.

| What you want                                                                                   | Where to go                           |
| ----------------------------------------------------------------------------------------------- | ------------------------------------- |
| Use your own node on a chain Rabby already supports, such as Ethereum, Base, or BNB Smart Chain | **Settings** > **Modify RPC URL**     |
| Add a chain Rabby doesn't support yet, such as a testnet                                        | **Settings** > **Add Custom Network** |

Custom RPC configuration is available on the Rabby browser extension. **Add Custom Network** is available on both the extension and the mobile app.

## Why point Rabby at your own node

By default, Rabby serves on-chain reads through its own nodes. Pointing Rabby at a Chainstack endpoint gives you:

* Reliability — a node endpoint of your own instead of a shared provider.
* Control — balance lookups, gas estimation, and transaction broadcasting run through a node you control.
* Performance — lower latency and consistent responses, especially during network congestion.

## What you need

* Your Chainstack node's HTTPS endpoint, with the authentication key, for the chain you want to change. See [View node access and credentials](/docs/manage-your-node#view-node-access-and-credentials).
* The [Rabby](https://rabby.io/) browser extension, installed and unlocked.
* For a network Rabby doesn't support yet, the target chain ID — look it up at [chainlist.org](https://chainlist.org/).

<Note>
  Make sure the endpoint's chain matches the chain you're editing. A Base endpoint set on Ethereum leaves Rabby unable to read balances or estimate gas.
</Note>

## Set a custom RPC on a supported chain

1. Open the Rabby extension and unlock your wallet.
2. Click the gear icon in the top-right corner of the popup to open **Settings**.
3. Click **Modify RPC URL**. The panel lists every chain that already has a custom RPC, each with its URL and an on/off toggle.
4. Click **Modify RPC URL** at the bottom of the panel, select the chain you want to change, and paste your Chainstack HTTPS endpoint, for example `https://ethereum-mainnet.core.chainstack.com/AUTH_KEY`.
5. Save the entry. The chain now appears in the list — leave its toggle on to route that chain through your endpoint.

<Note>
  A custom RPC replaces the node Rabby uses for that chain. To go back to Rabby's node, delete the custom RPC entry.
</Note>

## Add a network Rabby doesn't support

Use this flow for testnets and chains Rabby hasn't integrated.

1. Open the Rabby extension and unlock your wallet.
2. Go to **Settings** > **Add Custom Network**.
3. Enter the network name, RPC URL, chain ID, and currency symbol, or click **Quick add from Chainlist** to look the chain up automatically. Rabby doesn't supply RPC or chain ID values, so take the chain ID from [chainlist.org](https://chainlist.org/) and use your Chainstack endpoint as the RPC URL.
4. Save the network.
5. To see your assets on it, click the price chart on the homepage to open the portfolio list, then select the **Custom Network** tab.

<Note>
  On custom networks, Rabby shows token amounts only — price data and valuation aren't available, and transaction history isn't displayed. To see a token other than the native one, add it manually by contract address with **+ Token**.
</Note>

## Verify

Confirm the endpoint is healthy and on the chain you expect before you rely on it in Rabby:

<CodeGroup>
  ```bash cURL theme={"system"}
  curl YOUR_CHAINSTACK_ENDPOINT \
    -H 'content-type: application/json' \
    -d '{"jsonrpc":"2.0","method":"eth_chainId","params":[],"id":1}'
  ```
</CodeGroup>

The hex result must match the chain you set it on — for example, `0x1` for Ethereum Mainnet. Look up chain IDs at [chainlist.org](https://chainlist.org/).

For proof that traffic reaches your node, check the request metrics for your endpoint in the [Chainstack console](https://console.chainstack.com/). You'll see Rabby's read calls, such as `eth_call` and `eth_estimateGas`, as you use the wallet.

## Troubleshooting

* **Invalid URL on the RPC field.** Rabby shows this when the RPC is invalid or unreachable. Run the `eth_chainId` call above to check the URL and authentication key before adding it again.
* **Balances or gas estimates fail to load.** The endpoint is likely on the wrong chain. Confirm the chain ID with the `eth_chainId` call and make sure it matches the chain you set it on.
* **Revert to Rabby's node.** Delete the custom RPC entry under **Settings** > **Modify RPC URL**.
* **Use trusted RPC URLs only.** A custom RPC serves the on-chain state Rabby shows you and relays the transactions you sign, so a malicious endpoint can feed you false information before you sign. Only use endpoints you control or trust.

## See also

* [Adding a custom network to MetaMask](/docs/adding-a-custom-network-to-metamask)
* [Adding a custom RPC endpoint to Safe](/docs/adding-a-custom-rpc-endpoint-to-safe)
* [Manage your node](/docs/manage-your-node)
* [Authentication methods for different scenarios](/docs/authentication-methods-for-different-scenarios)
* [How to add and view custom networks](https://support.rabby.io/en/articles/14122934-how-to-add-and-view-custom-networks) — Rabby's official guide to the **Add Custom Network** flow
* [chainlist.org](https://chainlist.org/) — public registry of EVM chain IDs and metadata