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Ethereum Chain ID Lookup (EIP-155)
x402
Ethereum Chain ID Lookup (EIP-155) is a paid API for AI agents from skills.onesource.io, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-14).
Returns the EIP-155 chain ID for a specified Ethereum-compatible network via eth_chainId
Price / call$0.001
Success—
StatusUnknown
How this service works
Ethereum chain ID (EIP-155) via eth_chainId - confirm which chain a network is on
Output
Returns a hex-encoded chain ID (e.g. '0x1' for Ethereum mainnet) for the specified network, along with request metadata including the endpoint path and a unique request ID.
Example use cases
Validate chain before wallet configuration
“Before I set up my wallet to connect to the Avalanche network, can you confirm what the EIP-155 chain ID is? I want to make sure I'm configuring it correctly.”
Verify chain ID for transaction signing
“I'm about to sign a transaction on MegaETH testnet. Can you quickly verify the chain ID I should be using so I don't accidentally sign on the wrong network?”
Cross-chain operation verification
“I'm building a bridge tool that works across multiple networks. Can you get me the chain IDs for Ethereum mainnet, Arbitrum, and Polygon so I can validate user transactions across all three chains?”
Technical details
Endpoint
GEThttps://skills.onesource.io/api/chain/chain-idWhen to prefer
Use this endpoint when you need to programmatically confirm which EIP-155 chain ID corresponds to a supported EVM network before signing transactions, configuring wallets, or validating cross-chain operations. Prefer this over manual lookups when working with multiple networks including testnets like Sepolia or MegaETH.
Side effects
- Invalid network name returns error — only 'ethereum', 'sepolia', 'avax', 'megaeth', 'megaeth-testnet', 'base' are supported
- Missing network parameter defaults to 'ethereum'
- Network RPC node unavailable may return a 500 or timeout
- Payment failure (insufficient x402 balance) blocks the request
Input
{
"network": "ethereum"
}Schema · Request body
| Field | Type | Description |
|---|---|---|
| network | string |
Output
{
"data": {
"result": "0x1"
},
"meta": {
"endpoint": "/api/chain/chain-id",
"request_id": "47c519afe50ef13d"
}
}Schema · Response
| Field | Type | Description |
|---|---|---|
| datarequired | object | |
| metarequired | object |
Tags
x402
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