# BaseNFT Oracle x402 – NFT Ownership Verifier

> BaseNFT Oracle x402 – NFT Ownership Verifier is a paid API for AI agents from basenft-x402.vercel.app, paid per call via x402, $0.01/call, status unknown (last checked 2026-09-19).

Verifies whether a given wallet address holds tokens from a specified Base Mainnet NFT collection and returns ownership details including token count and block number.

## Facts

- Endpoint: GET https://basenft-x402.vercel.app/v1/verify-owner
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-19
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/basenft-oracle-x402-nft-ownership-verifier-064814f1
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_dQ4-a6ga26UGtVcJcs4Xl

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 basenft-oracle-x402-nft-ownership-verifier-064814f1
```

Example prompt: Check if the wallet 0x1234567890abcdef1234567890abcdef12345678 holds any NFTs from the Basenames collection on Base mainnet and tell me how many tokens they have.

## When to prefer this

Use this endpoint when you need real-time, on-chain verification of NFT ownership for a specific wallet on Base mainnet — particularly for Basenames or other Base-native collections. It is ideal for token-gating, airdrop eligibility checks, and holder authentication workflows where a simple true/false holder status plus token count is sufficient. Prefer this over general NFT APIs when you specifically need Base mainnet data with x402 micropayment-compatible access.

## Known failure modes

- Invalid wallet address format (not a valid 0x-prefixed 40-character hex address) returns a validation error
- Unknown or unsupported collection slug returns an error or empty collection metadata
- Network or RPC failure on Base mainnet may return a failed success flag
- Payment not completed via x402 protocol results in a 402 Payment Required response
- Rate limiting or service unavailability returns a 5xx error

## How this service works

Real-Time Base NFT Collection, Floor Price & Ownership Verification Oracle on Base Mainnet.

## Output

Returns a JSON object indicating whether the queried wallet is a holder (is_holder boolean), the number of tokens held (tokens_held integer), the block number at which the check was performed, the collection's contract address, metadata source, whether identity was verified, a timestamp (observed_at), and a success flag. Also surfaces any limitations associated with the lookup.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method",
    "queryParams"
   ],
   "properties": {
    "type": {
     "const": "http"
    },
    "method": {
     "const": "GET"
    },
    "queryParams": {
     "type": "object",
     "title": "OwnerRequest",
     "required": [
      "wallet"
     ],
     "properties": {
      "wallet": {
       "type": "string",
       "title": "Wallet",
       "pattern": "^0x[0-9a-fA-F]{40}$",
       "maxLength": 42,
       "minLength": 42
      },
      "collection": {
       "type": "string",
       "title": "Collection",
       "default": "basenames",
       "maxLength": 64,
       "minLength": 1
      }
     },
     "additionalProperties": false
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "properties": {
    "type": {
     "const": "json"
    },
    "example": {
     "type": "object",
     "required": [
      "success",
      "source",
      "wallet",
      "is_holder",
      "tokens_held",
      "block_number",
      "observed_at"
     ],
     "properties": {
      "source": {
       "type": "string"
      },
      "wallet": {
       "type": "string"
      },
      "network": {
       "const": "base-mainnet"
      },
      "success": {
       "type": "boolean"
      },
      "is_holder": {
       "type": "boolean"
      },
      "collection": {
       "type": "object",
       "required": [
        "address",
        "identity_verified",
        "metadata_source"
       ],
       "properties": {
        "name": {
         "type": [
          "string",
          "null"
         ]
        },
        "slug": {
         "type": [
          "string",
          "null"
         ]
        },
        "symbol": {
         "type": [
          "string",
          "null"
         ]
        },
        "address": {
         "type": "string",
         "pattern": "^0x[0-9a-fA-F]{40}$"
        },
        "metadata_source": {
         "enum": [
          "local_registry",
          "user_supplied_address"
         ]
        },
        "identity_verified": {
         "const": false
        }
       }
      },
      "limitations": {
       "type": "array",
       "items": {
        "type": "string"
       }
      },
      "observed_at": {
       "type": "string",
       "format": "date-time"
      },
      "tokens_held": {
       "type": "integer",
  
… (truncated)
```

## Response schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "address": {
   "type": "string"
  },
  "collection": {
   "type": "string"
  },
  "total_supply": {
   "type": "integer"
  },
  "floor_price_eth": {
   "type": "number"
  },
  "floor_price_usd": {
   "type": "number"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/basenft-oracle-x402-nft-ownership-verifier-064814f1/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from basenft-x402.vercel.app](https://www.zero.xyz/host/basenft-x402.vercel.app/llms.txt)