# Ozmium Portfolio Lookup – Base Address Token Balances

> Ozmium Portfolio Lookup – Base Address Token Balances is a paid API for AI agents from ozmium.org, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-14).

Returns all ERC-20 and native ETH holdings for a Base address with spam-screened balances and confidence-gated USD values (null when no reliable price exists)

## Facts

- Endpoint: GET https://ozmium.org/v1/portfolio/:address
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/ozmium-portfolio-lookup-base-address-token-balances-4de4bf5d
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_U8T4FobZ9Ev6juLMqVjGl

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 ozmium-portfolio-lookup-base-address-token-balances-4de4bf5d
```

Example prompt: What tokens does the Base wallet 0x3fC91A3afd70395Cd496C647d5a6CC9D4B2b7FAD hold, and what are they worth in USD?

## When to prefer this

Use this endpoint when you need a complete, spam-filtered snapshot of all ERC-20 and native ETH holdings for a specific Base mainnet address with honest USD valuations. Prefer it over generic blockchain explorers when you need machine-readable output with null-safety on prices (no fabricated zeros) suitable for automated agent workflows on the Base network.

## Known failure modes

- Invalid or malformed Ethereum address returns a 4xx error
- Address has no indexed activity on Base — returns an empty tokens array
- No reliable price feed for a token — usd field is null rather than 0
- Blockscout indexer lag may cause recently received tokens to be missing
- Payment failure (x402) if USDC balance is insufficient — call is not executed

## How this service works

Every ERC-20 + native ETH a Base address holds (Blockscout-indexed, spam-screened) with confidence-gated USD values: usd is null when no reliable price exists- NEVER a fabricated 0. GET /v1/portfolio/{address}.

## Output

A JSON object containing the queried address, network identifier, and an array of token objects each with a symbol, raw balance string, and a USD value (null if no reliable price is available — never a fabricated zero). Spam tokens are filtered out by the Blockscout indexer before the response is returned.

## 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"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET",
      "HEAD",
      "DELETE"
     ],
     "type": "string"
    },
    "pathParams": {
     "type": "object",
     "properties": {
      "address": {
       "type": "string"
      }
     }
    },
    "queryParams": {
     "type": "object",
     "properties": {}
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "properties": {
      "data": {
       "type": "object",
       "properties": {
        "tokens": {
         "type": "array",
         "items": {
          "type": "object",
          "properties": {
           "usd": {
            "type": "number"
           },
           "symbol": {
            "type": "string"
           },
           "balance": {
            "type": "string"
           }
          }
         }
        },
        "address": {
         "type": "string"
        }
       }
      },
      "network": {
       "type": "string"
      }
     }
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/ozmium-portfolio-lookup-base-address-token-balances-4de4bf5d/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from ozmium.org](https://www.zero.xyz/host/ozmium.org/llms.txt)