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OneSource Ethereum Contract Introspection
x402
OneSource Ethereum Contract Introspection is a paid API for AI agents from api.onesource.io, paid per call via x402, $0.005/call, status unknown (last checked 2026-09-08).
Fetches on-chain contract metadata (name, symbol, decimals, ERC interface support) for a given Ethereum or Sepolia contract address
Price / call$0.005
Success—
StatusUnknown
How this service works
Two data families for AI agents: live Ethereum mainnet, Sepolia testnet, and Robinhood Chain RPC reads, plus Deepstate on-chain market data (order books, trades, candles, and analytics). Pay per call or use batch/session mode: USDC on Base via x402, or pathUSD/USDC.e on Tempo via MPP. No API key required to start; a flat-rate monthly subscription is also available.
Output
Returns a JSON object with the contract's name, symbol, address, decimals, and a list of detected ERC interfaces (e.g. ERC20, ERC721, ERC1155) as introspected from the live Ethereum or Sepolia chain.
Example use cases
Example prompt
“What's the name, symbol, and decimals for the Ethereum contract at 0xdac17f958d2ee523a2206206994597c13d831ec7, and does it implement ERC20?”
Technical details
Endpoint
GEThttps://api.onesource.io/api/chain/contract/%7Baddress%7DWhen to prefer
Use this endpoint when you need to identify what token or contract is deployed at a specific Ethereum address — especially to resolve ERC20 token metadata (name, symbol, decimals) or determine whether a contract is an NFT (ERC721/ERC1155). Prefer it over generic JSON-RPC eth_call when you want structured, pre-parsed contract introspection without writing ABI calls yourself. Works on both Ethereum mainnet and Sepolia testnet without API keys.
Side effects
- Invalid address format (not a valid 0x-prefixed 40-char hex) returns a 400 error
- Address is an EOA (externally owned account), not a contract — returns empty or null metadata
- Contract does not implement standard name/symbol/decimals methods — partial or empty response
- Network unavailable or node sync issues — 503 or timeout
- Unsupported network value returns validation error
Input
{
"address": "0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48",
"network": "ethereum"
}Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Output
{
"data": {
"name": "USD Coin",
"symbol": "USDC",
"address": "0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48",
"is_erc20": false,
"is_erc165": false,
"is_erc721": false,
"is_erc1155": false,
"code_length": 2187,
"is_contract": true
},
"meta": {
"endpoint": "/api/chain/contract/0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48",
"request_id": "45dfac3eaad29bed"
}
}Schema · Response
{
"type": "json",
"example": {
"data": {
"name": "Tether USD",
"symbol": "USDT",
"address": "0xdac17f958d2ee523a2206206994597c13d831ec7",
"decimals": 6,
"is_erc20": true,
"is_erc165": false,
"is_erc721": false,
"interfaces": [
"ERC20"
],
"is_erc1155": false,
"code_length": 11075,
"is_contract": true
},
"meta": {
"endpoint": "/api/chain/contract/{address}",
"cost_usdc": "0.001",
"request_id": "00000000abcdef01",
"payment_chain": "base",
"payment_token": "USDC"
}
}
}Tags
x402
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