# ERC20/ERC721 Total Supply Lookup

> ERC20/ERC721 Total Supply Lookup is a paid API for AI agents from twin.unykorn.org, paid per call via x402, $0.003/call, status unknown (last checked 2026-10-01).

Returns the total token supply for a given ERC20 or ERC721 contract address on one of ten supported EVM chains

## Facts

- Endpoint: POST https://twin.unykorn.org/erc20-supply?utm_source=zero.xyz
- Price: $0.003/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-01
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/erc20-erc721-total-supply-lookup-c69fb287
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_KHsMYbnii4R0M8EzC5I0-

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 erc20-erc721-total-supply-lookup-c69fb287 -d '<json body>'
```

Example prompt: What is the total supply of the token at contract 0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48 on Ethereum?

## When to prefer this

Use this endpoint when you need a quick, pay-per-call lookup of a token's total supply across any of ten major EVM chains without running your own RPC infrastructure. Ideal for agents that need on-chain token metadata without a long-term API subscription. The x402 micropayment model ($0.003/call) makes it cost-effective for low-frequency or one-off queries.

## Known failure modes

- Invalid contract address format (not a valid 0x hex address) returns a validation error
- Unsupported chain name outside the allowed enum returns an error
- Contract address does not implement ERC20/ERC721 supply interface returns null or error
- Payment failure via x402 protocol results in 402 response and no data
- Network timeout or RPC node unavailability on the target chain

## How this service works

Total supply of an ERC20 or ERC721 contract — Genesis402 / UnyKorn Operator Network

## Output

Returns a JSON object containing: a boolean ok status, the supply type (erc20-supply), and a receipt object with the transaction hash, USD amount charged, receipt ID, and ISO8601 timestamp of when the data was generated.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "params": {
   "type": "object",
   "properties": {
    "chain": {
     "enum": [
      "ethereum",
      "base",
      "polygon",
      "arbitrum",
      "optimism",
      "bsc",
      "avalanche",
      "gnosis",
      "linea",
      "scroll"
     ],
     "type": "string"
    },
    "contract": {
     "type": "string",
     "pattern": "^0x[0-9a-fA-F]{40}$"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "ok": true,
  "type": "erc20-supply",
  "receipt": {
   "tx_hash": "0x<64hex>",
   "amount_usd": 0.003,
   "receipt_id": "g402-<16hex>"
  },
  "generated_at": "<iso8601>"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/erc20-erc721-total-supply-lookup-c69fb287/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from twin.unykorn.org](https://www.zero.xyz/host/twin.unykorn.org/llms.txt)