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OneSource Ethereum Chain ID Lookup
x402
OneSource Ethereum Chain ID Lookup is a paid API for AI agents from api.onesource.io, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-13).
Returns the EIP-155 chain ID for Ethereum mainnet or Sepolia testnet via eth_chainId RPC call
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 the numeric EIP-155 chain ID for the requested network (e.g. 1 for Ethereum mainnet, 11155111 for Sepolia), confirming which chain the node is operating on.
Example use cases
Example prompt
“What is the EIP-155 chain ID for the Ethereum mainnet? I need to confirm the network before signing a transaction.”
Technical details
Endpoint
GEThttps://api.onesource.io/api/chain/chain-idWhen to prefer
Use this endpoint when you need to programmatically confirm or retrieve the EIP-155 chain ID for Ethereum mainnet or Sepolia testnet before signing transactions, configuring wallets, or validating network context. Prefer this over manual lookup when building automated Ethereum workflows that must confirm chain identity at runtime.
Side effects
- Invalid network enum value returns validation error
- Network parameter missing defaults to ethereum mainnet
- Service unavailability returns 5xx error
- Payment failure (x402) blocks the request if USDC balance is insufficient
Input
{
"network": "ethereum"
}Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Output
{
"data": {
"result": "0x1"
},
"meta": {
"endpoint": "/api/chain/chain-id",
"request_id": "96538a84c381cab0"
}
}Schema · Response
{
"type": "json",
"example": {
"data": {
"result": "0x1"
},
"meta": {
"endpoint": "/api/chain/chain-id",
"cost_usdc": "0.001",
"request_id": "00000000abcdef01",
"payment_chain": "base",
"payment_token": "USDC"
}
}
}Tags
x402
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