# Arbitrum NFT Balance (balanceOf)

> Arbitrum NFT Balance (balanceOf) is a paid API for AI agents from agent-data-tools.revmesh2074.workers.dev, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-24).

Returns the number of ERC-721 NFTs a wallet holds in a specific collection on Arbitrum One, plus the collection name and symbol.

## Facts

- Endpoint: GET https://agent-data-tools.revmesh2074.workers.dev/arb/nft-balance?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-24
- Activations on Zero: 0
- Provider: agent-data-tools.revmesh2074.workers.dev
- Website: https://agent-data-tools.revmesh2074.workers.dev
- Canonical page: https://www.zero.xyz/c/agent-data-tools-revmesh2074-workers-dev-arbitrum-nft-balance-balanceof-bbe0d3b8
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_MZGRm3hfemTLI3P9lTR-J

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 agent-data-tools-revmesh2074-workers-dev-arbitrum-nft-balance-balanceof-bbe0d3b8
```

Example prompt: Check how many NFTs wallet 0xAbC...123 holds in the Arbitrum ERC-721 collection at contract 0xDef...456 — I need to know if they qualify for token-gated access.

## When to prefer this

Use this endpoint when you need the aggregate NFT count a wallet holds in a given ERC-721 collection on Arbitrum One — ideal for token-gating checks, holder verification, and dashboard displays. If you need to find who owns a specific token ID rather than a count, use the arb_nft_owner endpoint instead. Prefer this over generic blockchain RPC calls when you also want the collection name and symbol alongside the balance in one call.

## Known failure modes

- 404 — contract address not found on Arbitrum One (not charged)
- 422 — contract exists but does not implement ERC-721 interface (not charged)
- Invalid 0x address format may cause a 400 or error response
- Network/RPC timeout from Arbitrum node
- Wallet has zero balance — returns balance: '0', not an error

## How this service works

How many NFTs of one ERC-721 collection a wallet holds on Arbitrum One (balanceOf), with the collection's name and symbol. Use to check a holder before a token-gated action or to see whether a wallet still holds a collection; for who holds one token id use arb_nft_owner. Both inputs are 0x addresses; a missing contract is 404, a contract that is not ERC-721 422, both uncharged.

## Output

Returns a JSON object with the wallet's NFT balance (as a string), the collection's name and symbol, the chain name ('arbitrum'), the chainId (42161), and the queried wallet and contract addresses. A 404 means the contract does not exist; a 422 means the contract exists but is not ERC-721; neither error is charged.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "required": [
  "contract",
  "address"
 ],
 "properties": {
  "address": {
   "type": "string",
   "description": "0x wallet address"
  },
  "contract": {
   "type": "string",
   "description": "0x ERC-721 collection contract address"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "name": {
   "type": "string"
  },
  "chain": {
   "type": "string"
  },
  "symbol": {
   "type": "string"
  },
  "address": {
   "type": "string"
  },
  "balance": {
   "type": "string"
  },
  "chainId": {
   "type": "number"
  },
  "contract": {
   "type": "string"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/agent-data-tools-revmesh2074-workers-dev-arbitrum-nft-balance-balanceof-bbe0d3b8/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from agent-data-tools.revmesh2074.workers.dev](https://www.zero.xyz/host/agent-data-tools.revmesh2074.workers.dev/llms.txt)