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Account Nonce
x402
Account Nonce is a paid API for AI agents from x402-echo-service.onrender.com, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-14).
Returns the current transaction count (nonce) for a Base blockchain address, optionally including pending mempool transactions.
Price / call$0.001
Success—
StatusUnknown
How this service works
Read the transaction count of an address on Base. POST {"address":"0x..."} with an optional {"pending":true} to include the mempool. Returns the nonce an agent should use for its next transaction.
Output
Returns the nonce (transaction count) as an integer representing how many transactions the address has sent. If pending:true is passed, the count includes unconfirmed transactions currently in the mempool, giving the correct nonce for a new transaction to be submitted immediately after any pending ones.
Example use cases
Pre-flight check before signing transaction
“Before I submit a new transaction from 0xAbC123..., what nonce should I use? Include pending transactions so I don't accidentally reuse one.”
Diagnosing stuck pending transactions
“I think I have a stuck pending transaction on Base from 0xDef456... — can you check the confirmed nonce and the pending nonce so I can figure out what's stuck?”
Auditing wallet transaction history
“How many transactions has wallet 0x789Ghi... ever sent on Base? I want the confirmed count, not including anything still in the mempool.”
Technical details
Endpoint
POSThttps://x402-echo-service.onrender.com/chain/nonceWhen to prefer
Use this endpoint when an agent needs to construct and sign a raw transaction on Base and must determine the correct nonce to avoid nonce conflicts or transaction rejection. Prefer over manual RPC calls when you need a simple, paid-per-use REST interface without managing a Base node or Web3 library. The pending:true flag is especially valuable when multiple transactions are being submitted in quick succession.
Side effects
- Invalid or malformed Ethereum address returns an error response
- Address not found on Base (zero transactions) returns 0, which is valid and not an error
- Network or RPC errors from the Base node may cause timeouts or 5xx responses
- Missing required 'address' field returns a 400-level validation error
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| address | string | |
| pending | boolean |
Tags
x402
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