ERC20 balance API for AI agent

$0.002 USDC per call on Base · No signup · No API key · x402 v2

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What it does

Read ERC20 balances and EVM chain data. Query token balances, allowances, and basic onchain state for any EVM address on Base and Ethereum mainnet. No node required.

Data source: Base + Ethereum RPC

How to call (for AI agents)

No account. No API key. Every endpoint speaks x402 v2:

Call the endpoint → you get 402 Payment Required with the price
Pay $0.002 USDC on Base (eip155:8453)
Retry with the X-PAYMENT header → 200 with JSON

curl -X POST "https://api.mekongtradeintel.com/chain/api/chain" \
  -H "Content-Type: application/json" \
  -d '{   "address": "0x198f3895551B309fF5C5F59e690FB0823d10EA93",   "token": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913" }'

Input

Param	Type	Description
`address`	string (body JSON)	Wallet or contract address 0x...
`token`	string (body JSON, optional)	ERC20 contract address; omit for native balance

Example request & response

Request

{
  "address": "0x198f3895551B309fF5C5F59e690FB0823d10EA93",
  "token": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913"
}

Response

{
  "address": "0x198f...EA93",
  "token": "USDC",
  "balance": "0.068",
  "decimals": 6,
  "network": "eip155:8453"
}

Payment

x402 v2 · exact scheme · USDC 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Base (eip155:8453).
Facilitators: Coinbase CDP and PayAI (no API key needed for either).

FAQ

Which networks are supported?
Base (eip155:8453) and Ethereum mainnet (eip155:1).

Can I batch multiple addresses?
One address per call. Batch by making parallel calls.

Is this real-time?
Reads the latest finalized block, typically <15s behind head.

Do I need an API key?
No. This API uses x402: call the endpoint, receive a 402 Payment Required with the price, pay in USDC on Base, and retry with proof of payment. No signup, no API key, no account.

Which facilitators are supported?
Both Coinbase CDP and PayAI facilitators are supported for x402 v2 exact payments on Base (eip155:8453).

What if my payment is too low?
The facilitator verifies the on-chain amount against the price. If underpaid, you get 402 again; pay the full amount and retry.

More APIs for AI agents

Part of the x402 API Collection — 37 pay-per-call endpoints, $0.0008–$1.50/call. Full catalog: https://api.mekongtradeintel.com/.well-known/x402 · pricing