# skills.onesource.io Wallet Nonce Lookup

> skills.onesource.io Wallet Nonce Lookup is a paid API for AI agents from skills.onesource.io, paid per call via x402, $0.003000/call, status unknown (last checked 2026-09-13).

Fetches the current on-chain transaction nonce for a given Ethereum-compatible wallet address at a specified block.

## Facts

- Endpoint: GET https://skills.onesource.io/api/chain/nonce/0xd8da6bf26964af9d7eed9e03e53415d37aa96045
- Price: $0.003000/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-13
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/skills-onesource-io-aa670e7b
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_ECDZIr-3CqieAiTxNfjbE

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-aa670e7b
```

Example prompt: What is the current on-chain nonce for wallet 0xd8da6bf26964af9d7eed9e03e53415d37aa96045 on Ethereum mainnet at the latest block?

## When to prefer this

Use this endpoint when you need to programmatically determine the current transaction nonce for an Ethereum-compatible wallet on supported networks (ethereum, base, avax, sepolia, megaeth). Ideal for transaction construction, replay attack prevention checks, or auditing wallet activity count. Supports multiple block tags including latest, pending, and finalized.

## Known failure modes

- Invalid wallet address format returns validation error
- Unsupported network value returns enum mismatch error
- Invalid block reference (malformed hex) returns parsing error
- Network timeout or RPC node unavailability returns 5xx error
- Address with no transactions returns nonce of 0x0

## How this service works

Fetches the current nonce for a given wallet address on-chain.

## Output

Returns a hex-encoded nonce value (e.g. '0x678') representing the number of transactions sent from the wallet address, along with request metadata including the endpoint path and a unique request ID.

## Example request

```json
{
 "block": "latest",
 "network": "ethereum"
}
```

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "block": {
   "oneOf": [
    {
     "type": "integer",
     "minimum": 0
    },
    {
     "enum": [
      "latest",
      "pending",
      "earliest",
      "safe",
      "finalized"
     ],
     "type": "string"
    },
    {
     "type": "string",
     "pattern": "^0x[a-fA-F0-9]+$"
    }
   ]
  },
  "address": {
   "type": "string",
   "pattern": "^0x[a-fA-F0-9]{40}$"
  },
  "network": {
   "enum": [
    "ethereum",
    "sepolia",
    "avax",
    "megaeth",
    "megaeth-testnet",
    "base"
   ],
   "type": "string",
   "default": "ethereum"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "object",
 "required": [
  "data",
  "meta"
 ],
 "properties": {
  "data": {
   "type": "object",
   "required": [
    "nonce"
   ],
   "properties": {
    "nonce": {
     "type": "string"
    }
   }
  },
  "meta": {
   "type": "object",
   "required": [
    "endpoint",
    "request_id"
   ],
   "properties": {
    "endpoint": {
     "type": "string"
    },
    "request_id": {
     "type": "string"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/skills-onesource-io-aa670e7b/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)