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Ethereum Portfolio Balance Lookup (ETH + ERC-20)
x402
Ethereum Portfolio Balance Lookup (ETH + ERC-20) is a paid API for AI agents from agentshelf.syntexa.ch, paid per call via x402, $0.003/call, status unknown (last checked 2026-10-30).
Fetches native ETH balance plus up to 20 ERC-20 token balances for a given Ethereum mainnet address using Multicall3 batch reads.
Price / call$0.003
Success—
StatusUnknown
How this service works
Call when an agent needs native ETH plus up to 20 ERC-20 balances for one Ethereum address. Send address and an optional tokens list; omit tokens for Circle USDC. Multicall3 batches the reads. Read-only. No spend. Send JSON {"address":"0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045","tokens":["0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48"]}. Exact $0.003 USDC on Base. Try unpaid POST /v1/sandbox/eth-portfolio first.
Output
Returns the native ETH balance alongside balances for each specified ERC-20 token contract address (defaulting to Circle USDC if no token list is provided) for the queried Ethereum mainnet address, batched via Multicall3 for efficiency.
Example use cases
DeFi portfolio snapshot before rebalancing
“Can you check the ETH and USDC balances for wallet 0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045 so I know what I'm working with before I decide how to rebalance?”
Airdrop eligibility balance check
“I need to verify whether address 0xAb5801a7D398351b8bE11C439e05C5B3259aeC9B holds at least some USDC at 0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48 and also its ETH balance — can you pull that up?”
Multi-token treasury audit
“Pull the balances for ETH plus these three tokens — USDC 0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48, DAI 0x6B175474E89094C44Da98b954EedeAC495271d0F, and WETH 0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2 — for our treasury wallet 0x742d35Cc6634C0532925a3b844Bc454e4438f44e.”
Technical details
Endpoint
POSThttps://agentshelf.syntexa.ch/v1/eth-portfolio?utm_source=zero.xyzWhen to prefer
Choose this endpoint when you need to read native ETH plus multiple ERC-20 balances for a single Ethereum mainnet address in one efficient batched call. It is particularly well-suited for portfolio snapshots, treasury audits, or pre-transaction checks where you want both ETH and up to 20 tokens at once without making separate RPC calls. Prefer this over generic blockchain RPC endpoints when you want a simple JSON API without managing node infrastructure.
Side effects
- Invalid or malformed Ethereum address returns an error
- Empty token array is rejected — must omit or provide at least one address
- More than 20 ERC-20 addresses in the tokens list is rejected
- Invalid ERC-20 contract address may return zero balance or error
- Payment of exactly $0.003 USDC on Base must succeed; underpayment rejects the call
- Sandbox endpoint (/v1/sandbox/eth-portfolio) available for unpaid testing
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| tokens | array | Up to 20 ERC-20 addresses. Example: ["0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48"]. Omit the field for Circle USDC. An empty list is rejected. |
| address | string | Holder on Ethereum mainnet. Example: 0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045. Returns native ETH plus ERC-20 balances. EIP-55 or all one case. |
Tags
x402
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