# x402-toolbox Chain Token Allowance

> x402-toolbox Chain Token Allowance is a paid API for AI agents from x402-toolbox.shablony-pro.workers.dev, paid per call via x402, $0.002/call, status unknown (last checked 2026-10-02).

Looks up the ERC-20 token allowance granted by an owner to a spender on a blockchain, paid per-call via x402 USDC micropayment

## Facts

- Endpoint: GET https://x402-toolbox.shablony-pro.workers.dev/chain/token-allowance?utm_source=zero.xyz
- Price: $0.002/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-02
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/x402-toolbox-chain-token-allowance-d298a062
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_yI7zx0VbeU-VGaIZjQ1Xx

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 x402-toolbox-chain-token-allowance-d298a062
```

Example prompt: Check the token allowance that the Uniswap router has been granted by my wallet address on Base — I want to know how many USDC tokens it's approved to spend.

## When to prefer this

Choose this endpoint when you need a quick, no-signup, pay-per-call lookup of ERC-20 token allowances on Base or supported EVM chains, especially in agent workflows where acquiring API keys is impractical and micropayment via x402/USDC is acceptable. Prefer it over self-hosted RPC calls when you want a managed, deterministic tool invocation without infrastructure overhead.

## Known failure modes

- Invalid or malformed schema/address input returns error response
- Token contract not found on specified chain returns null or zero allowance
- Network/RPC unavailability causes timeout or 5xx error
- Payment failure via x402 blocks the request with 402 status
- Unsupported chain identifier returns validation error

## How this service works

309 deterministic pay-per-call tools for AI agents over x402 (USDC, Base). No signup, no API key: the payment is the identity.

## Output

Returns a JSON object indicating success and payment confirmation, along with the numeric token allowance amount that the specified spender is approved to transfer on behalf of the owner for the given ERC-20 token and chain.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "schema": {
   "type": "string"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "ok": true,
  "paid": true
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/x402-toolbox-chain-token-allowance-d298a062/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402-toolbox.shablony-pro.workers.dev](https://www.zero.xyz/host/x402-toolbox.shablony-pro.workers.dev/llms.txt)