# chain-erc20-allowance

> chain-erc20-allowance is a paid API for AI agents from chain.intel.rallylive.ca, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-02).

Returns the ERC-20 token allowance a wallet owner has granted to a spender, including whether the allowance is unlimited, across multiple EVM chains.

## Facts

- Endpoint: GET https://chain.intel.rallylive.ca/chain/allowance?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-02
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/chain-erc20-allowance-70e7e83f
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_KH4QQslIc25ERTzA6Z3-B

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 chain-erc20-allowance-70e7e83f
```

Example prompt: What's the USDC allowance that my wallet 0xAbC...123 has granted to the Uniswap router 0xDef...456 on Base — and is it unlimited?

## When to prefer this

Use this endpoint when you need to programmatically check ERC-20 spending approvals across Base and other major EVM chains in a single call. It is ideal for security audits, DeFi automation agents that need to verify approvals before executing swaps or deposits, and wallet monitoring tools that track unlimited approvals. Prefer this over a raw RPC call when you need a simple, paid-per-call API without managing your own node infrastructure across multiple chains.

## Known failure modes

- Invalid or malformed token/owner/spender address returns an error
- Unsupported chain prefix returns an error or empty result
- Contract address is not an ERC-20 token returns an unexpected result
- Network congestion or RPC issues may cause timeouts
- Missing required input parameters (token, owner, spender) returns validation error

## How this service works

ERC-20 allowance a wallet has granted a spender, and whether it is unlimited: send "token,owner,spender". Default chain Base; prefix another: ethereum:, arbitrum:, optimism:, polygon:, bsc:. $0.01 per call.

## Output

Returns the numeric allowance amount the owner wallet has approved for the spender to spend of the given ERC-20 token, plus a boolean or flag indicating whether the allowance is effectively unlimited (max uint256). Covers Base by default; other chains can be prefixed (ethereum:, arbitrum:, optimism:, polygon:, bsc:).

## 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"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "properties": {}
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/chain-erc20-allowance-70e7e83f/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from chain.intel.rallylive.ca](https://www.zero.xyz/host/chain.intel.rallylive.ca/llms.txt)