Chain Status

Overview

The chain status endpoint provides information about all blockchain chains configured in your Lasso RPC instance.

Endpoint

GET /api/chains

Response

Returns a JSON object containing an array of configured chains:

array

required

Array of chain configuration objects

Show chain properties

string

required

The numeric chain ID as a string (e.g., “1” for Ethereum Mainnet)

string

required

Human-readable name of the blockchain

string

required

Internal identifier used in API paths and configuration

boolean

required

Whether this chain is currently supported (always true for configured chains)

Response Example

{
  "chains": [
    {
      "chain_id": "1",
      "name": "Ethereum Mainnet",
      "chain_name": "ethereum",
      "supported": true
    },
    {
      "chain_id": "137",
      "name": "Polygon",
      "chain_name": "polygon",
      "supported": true
    },
    {
      "chain_id": "42161",
      "name": "Arbitrum One",
      "chain_name": "arbitrum",
      "supported": true
    }
  ]
}

Use Cases

Discover Available Chains

Query which chains are configured and ready to use:

curl http://localhost:4000/api/chains

Validate Chain Configuration

Check if a specific chain is configured before making RPC requests:

# Check if Ethereum is configured
chains=$(curl -s http://localhost:4000/api/chains)
has_ethereum=$(echo $chains | jq '.chains[] | select(.chain_name=="ethereum") | .chain_id')

if [ -n "$has_ethereum" ]; then
  echo "Ethereum is configured with chain_id: $has_ethereum"
fi

Dynamic Client Configuration

Use this endpoint to dynamically configure multi-chain applications:

const response = await fetch('http://localhost:4000/api/chains');
const { chains } = await response.json();

// Build RPC endpoints for each chain
const rpcEndpoints = chains.reduce((acc, chain) => {
  acc[chain.chain_name] = `http://localhost:4000/rpc/${chain.chain_id}`;
  return acc;
}, {});

console.log(rpcEndpoints);
// {
//   ethereum: 'http://localhost:4000/rpc/1',
//   polygon: 'http://localhost:4000/rpc/137',
//   arbitrum: 'http://localhost:4000/rpc/42161'
// }

Chain Name vs Chain ID

Lasso RPC supports referencing chains by both their numeric chain_id and their chain_name:

chain_id: Standard EVM chain identifier (e.g., 1, 137, 42161)
chain_name: Human-friendly identifier used in configuration files (e.g., ethereum, polygon, arbitrum)

Both can be used in RPC endpoint paths:

# Using chain_id
curl -X POST http://localhost:4000/rpc/1 \
  -H "Content-Type: application/json" \
  -d '{"jsonrpc":"2.0","method":"eth_blockNumber","params":[],"id":1}'

# Using chain_name (if supported by your configuration)
curl -X POST http://localhost:4000/rpc/ethereum \
  -H "Content-Type: application/json" \
  -d '{"jsonrpc":"2.0","method":"eth_blockNumber","params":[],"id":1}'

Notes

The list of chains is determined by your configuration file
All returned chains have supported: true as unsupported chains are not included in the response
Chain configurations are loaded at startup and do not change without restarting the instance
This endpoint is useful for service discovery in multi-chain applications

HTTP API

WebSocket API

Management API

Reference

Chain Status

Overview

Endpoint

Response

Response Example

Use Cases

Discover Available Chains

Validate Chain Configuration

Dynamic Client Configuration

Chain Name vs Chain ID

Notes

​Overview

​Endpoint

​Response

​Response Example

​Use Cases

​Discover Available Chains

​Validate Chain Configuration

​Dynamic Client Configuration

​Chain Name vs Chain ID

​Notes

Overview

Endpoint

Response

Response Example

Use Cases

Discover Available Chains

Validate Chain Configuration

Dynamic Client Configuration

Chain Name vs Chain ID

Notes