# Ethereum Wallet Transaction Nonce Lookup

> Ethereum Wallet Transaction Nonce Lookup is a paid API for AI agents from skills.onesource.io, paid per call via x402, $0.003/call, status unknown (last checked 2026-09-15).

Returns the next transaction nonce (eth_getTransactionCount) for any Ethereum-compatible wallet address at a given block

## Facts

- Endpoint: GET https://skills.onesource.io/api/chain/nonce/:address
- Price: $0.003/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/skills-onesource-io-0a918a11
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_Od-WiE2Wewy7Jl5RYZyto

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability skills-onesource-io-0a918a11
```

Example prompt: What's the current nonce for Ethereum wallet 0x1234567890123456789012345678901234567890 on mainnet at the latest block — how many transactions has it sent so far?

## When to prefer this

Use this endpoint when you need the transaction nonce for an Ethereum-compatible wallet address, especially when constructing or broadcasting transactions, auditing wallet activity, or checking how many transactions an address has sent. Prefer this over raw RPC calls when you want a managed, pay-per-use API with multi-network support including Base, Avalanche, and testnets.

## Known failure modes

- Invalid address format (not a 40-char hex with 0x prefix) returns a validation error
- Unsupported network name returns an error (must be one of: ethereum, sepolia, avax, megaeth, megaeth-testnet, base)
- Invalid block tag or number returns an RPC error
- Address with no transaction history returns nonce 0x0
- RPC node unavailability may cause timeout or 5xx response
- Payment failure (402) if USDC balance is insufficient

## How this service works

Next transaction nonce for any Ethereum wallet via eth_getTransactionCount - how many txs it has sent

## Output

Returns a hex-encoded nonce value (e.g. '0x1a') representing how many transactions the wallet has sent, plus endpoint and request ID metadata. The nonce indicates the next sequence number to use for a new transaction from that address.

## Example request

```json
{
 "block": "latest",
 "address": "0x1234567890123456789012345678901234567890",
 "network": "ethereum"
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/skills-onesource-io-0a918a11/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from skills.onesource.io](https://www.zero.xyz/host/skills.onesource.io/llms.txt)