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Keystone Opportunity API – Base Wallet Lookup
x402
Keystone Opportunity API – Base Wallet Lookup is a paid API for AI agents from keystone-opportunity-api.keystone-opportunity.workers.dev, paid per call via x402, $0.02/call, status unknown (last checked 2026-09-13).
Fetches ETH and USDC balances, transaction count, and contract status for a given Base network wallet address, paid via x402/USDC onchain.
Price / call$0.02
Success—
StatusUnknown
How this service works
Low-cost, deterministic x402 utilities for autonomous agents on Base. Every /v1 route is priced in USDC and settles onchain via the x402 protocol; discover and pay programmatically through the x402 Bazaar. No API keys, no subscriptions.
Output
Returns a JSON object containing the wallet's ETH balance (float), USDC balance (float), the queried address, chain ID (8453 for Base), network name ('base'), a boolean indicating whether the address is a smart contract, the transaction count, and the timestamp of observation.
Example use cases
DeFi portfolio balance check
“Can you pull the current ETH and USDC balances for my Base wallet 0xAbC1234567890abcdef1234567890abcdef12345 and tell me how many transactions it's made?”
Contract vs EOA verification
“I need to know whether the Base address 0xdEaD000000000000000042069420694206942069 is a smart contract or a regular wallet — can you check?”
Autonomous agent treasury audit
“Check the ETH and USDC holdings for the agent treasury wallet 0xBEEF000000000000000000000000000000000001 on Base so I can decide if it needs a top-up.”
Technical details
Endpoint
GEThttps://keystone-opportunity-api.keystone-opportunity.workers.dev/v1/base/wallet/%7Baddress%7DWhen to prefer
Choose this endpoint when you need a fast, no-API-key, onchain-settled lookup of ETH and USDC balances plus contract/EOA status for a Base network address. Ideal for autonomous agents that already operate within the x402 payment ecosystem and need deterministic, programmatic wallet data without managing API subscriptions.
Side effects
- Invalid or malformed wallet address returns an error or empty result
- Address not yet active on Base (zero transactions) may return zeroed balances
- Network congestion or RPC issues may cause stale or delayed data
- x402 payment failure (insufficient USDC, wrong facilitator) blocks the request
- Cloudflare Worker timeout on high-load periods
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| properties | string |
Output
Schema · Response
{
"type": "json",
"example": {
"eth": 0.0123,
"usdc": 4.77,
"address": "0x0000000000000000000000000000000000000000",
"chainId": 8453,
"network": "base",
"contract": false,
"observedAt": "2026-07-26T00:00:00.000Z",
"transactionCount": 12
}
}Tags
x402
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