How to Add a Custom RPC Endpoint in Rabby Wallet for a New EVM Network?

Adding a Custom RPC Endpoint in Rabby Wallet

Rabby Wallet supports seamless integration with any EVM-compatible blockchain through manual RPC configuration. This capability enables users to interact directly with emerging Layer 1s, testnets, and application-specific chains without waiting for official wallet support.

Prerequisites for Network Configuration

1. A valid RPC URL endpoint—must be HTTPS or WSS, not HTTP, and must respond to eth_chainId and eth_blockNumber calls.2. The correct chain ID as a decimal or hexadecimal integer—mismatched IDs will cause transaction rejections.3. Native token symbol (e.g., ETH, BNB, MATIC) and its decimal precision—critical for accurate balance display and gas estimation.4. Block explorer URL with {tx} or {address} placeholders—Rabby uses this to link transactions and accounts.5. Optional but recommended: a custom RPC name and network icon URL for improved UI recognition.

Step-by-Step Manual Setup Process

1. Open Rabby Wallet extension and click the network selector in the top-right corner.2. Select “Add Network” from the dropdown menu.3. Choose “Custom RPC” instead of predefined networks.4. Enter the RPC URL into the “RPC URL” field—verify connectivity using curl or browser dev tools before proceeding.5. Input the chain ID—Rabby validates this against known public chains and warns if it overlaps with Ethereum Mainnet (1), Sepolia (11155111), or other widely used IDs.6. Fill in the native currency symbol and decimals—setting decimals to 18 when uncertain is safe for most tokens.7. Paste the block explorer URL—ensure {tx} appears exactly once for transaction links and {address} for account pages.8. Click “Save” and confirm the new network appears in the selector with correct icon and label.

Verification and Troubleshooting Steps

1. Switch to the newly added network and check if the balance displays zero or “Loading”—a persistent loading state indicates RPC timeout or CORS misconfiguration.2. Initiate a simple read call such as eth_getBalance via Rabby’s built-in console or external dApp to verify endpoint responsiveness.3. Attempt to sign and broadcast a low-gas transaction—observe whether the transaction hash appears on the block explorer within expected finality time.4. Inspect browser console logs for errors like “Failed to fetch”, “CORS policy blocked”, or “Invalid JSON-RPC response”—these point to infrastructure-level issues.5. Confirm that the network’s consensus layer matches EVM semantics—non-EVM chains (e.g., Solana, Cosmos SDK) will fail silently or produce malformed signatures.

Frequently Asked Questions

Q: Can I add multiple RPC endpoints for the same chain ID?A: Yes. Rabby allows multiple RPCs per chain ID. It attempts them sequentially upon failure and caches the fastest responsive endpoint for subsequent use.

Q: Why does Rabby reject my RPC URL ending in /v1 or /jsonrpc?A: Rabby enforces strict URL validation. Trailing slashes are permitted only if the full path resolves to a functional JSON-RPC endpoint. Some proxy services append version paths that break standard compliance—test with curl -X POST -H 'Content-Type: application/json' --data '{'jsonrpc':'2.0','method':'eth_chainId','params':[],'id':1}' YOUR_URL to confirm.

Q: Is it safe to use public RPC endpoints provided by third-party aggregators?A: Public endpoints carry inherent privacy risks—your transaction payloads, addresses, and query patterns may be logged or throttled. For production dApp interaction, self-hosted or permissioned RPCs are strongly advised.

Q: What happens if I enter an incorrect chain ID that conflicts with an existing network?A: Rabby prevents duplicate chain IDs during setup. If the ID matches an already configured network, it merges the new RPC into the existing network’s fallback list rather than creating a separate entry.