# Revoke Calldata Builder

> Revoke Calldata Builder is a paid API for AI agents from 402.com.tr, paid per call via x402, $0.02/call, status unknown (last checked 2026-09-13).

Builds the ready-to-sign revoke transaction (contract address + calldata for approve(spender,0)) and reads the live current allowance for a token/spender pair on Base.

## Facts

- Endpoint: GET https://402.com.tr/api/x402/revoke-builder
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-13
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/revoke-calldata-builder-4811f80d
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_qONgklK_PtxoaFjwacPvU

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 revoke-calldata-builder-4811f80d
```

Example prompt: Build me a revoke transaction for the USDC token contract 0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48 with spender 0x1111111254EEB25477B68fb85Ed929f73A960582 — and check what the current live allowance is for my wallet 0xYourWalletAddress.

## When to prefer this

Choose this endpoint when you already know which token/spender pair to revoke (e.g. after running approval-advisor) and need the exact signed-ready calldata plus a live allowance confirmation — it bridges the gap between identifying a risky approval and actually executing the revocation, saving you from manually encoding approve(spender,0) calldata.

## Known failure modes

- Invalid token contract address returns an error or zero response
- Invalid spender address format causes a 400-level error
- Token contract does not implement ERC-20 approve, causing calldata generation failure
- Wallet address omitted means live allowance cannot be read
- RPC read failure on Base may cause allowance lookup to timeout
- Unrecognized contract ABI may return malformed calldata

## How this service works

approval-advisor tells you WHAT to revoke; this builds the HOW: the ready-to-sign transaction (to + calldata) for approve(spender, 0) on a token, plus the live current allowance read from Base (flags unlimited, or 'already revoked'). Hand the result straight to a wallet or agent signer — the action half of approval hygiene.

## Output

Returns the destination contract address (to) and hex calldata encoding approve(spender, 0) ready for signing, plus the live current allowance value fetched from Base mainnet — flagged as unlimited if it equals max uint256, or marked as already revoked if it is zero.

## 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"
    },
    "pathParams": {
     "type": "object"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "token",
      "spender"
     ],
     "properties": {
      "token": {
       "type": "string",
       "description": "Token contract"
      },
      "wallet": {
       "type": "string",
       "description": "Your wallet (optional, reads live allowance)"
      },
      "spender": {
       "type": "string",
       "description": "Spender to revoke"
      }
     }
    }
   },
   "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/revoke-calldata-builder-4811f80d/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from 402.com.tr](https://www.zero.xyz/host/402.com.tr/llms.txt)