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x402 Pre-Trade Check
x402
x402 Pre-Trade Check is a paid API for AI agents from x402-gateway-production-1f21.up.railway.app, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-10).
Performs a pre-trade readiness check by verifying token allowances, balances, and approval status for a given wallet address and spender before executing an on-chain trade or payment.
Price / call$0.01
Success—
StatusUnknown
How this service works
Pre-trade context bundle for autonomous crypto agents: wallet balances, ERC-20 allowance to a spender, current gas/base fee, realtime price, 24h statistics and best bid/ask spread. Use immediately before swaps, recurring payments or automated execution. This endpoint provides data only and never submits a trade.
Output
Returns a JSON object with a status field (e.g. 'ready') indicating whether the wallet is pre-cleared for the trade, including allowance and balance validation results for the specified token contract, spender, and product on the target network.
Example use cases
Pre-swap allowance check on Base
“Before I do the swap, can you verify that my wallet 0xAbC1234567890abcdef1234567890abcdef123456 has enough allowance set for spender 0xDEF987654321fedcba9876543210fedcba987654 on token contract 0x833589fcd6edb6e08f4c7c32d4f71b54bda02913 on Base for product USDC-ETH?”
DeFi bot pre-trade readiness check
“My trading bot needs to verify that wallet 0x1111222233334444555566667777888899990000 is approved to let spender 0xAAAABBBBCCCCDDDDEEEEFFFF0000111122223333 move token 0x4200000000000000000000000000000000000006 on Base before it executes the BTC-USD trade — can you run that pre-trade check?”
Ethereum allowance verification before payment
“Check if wallet 0x9999888877776666555544443333222211110000 has given approval to spender 0xCCCCDDDDEEEEFFFF0000111122223333AAAABBBB for token contract 0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48 on Ethereum for product ID PAY-USD, and also check balances for tokens 0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48 and 0xdAC17F958D2ee523a2206206994597C13D831ec7.”
Technical details
Endpoint
POSThttps://x402-gateway-production-1f21.up.railway.app/agent/pretrade?utm_source=zero.xyzWhen to prefer
Use this endpoint when an AI agent or automated trading system needs to confirm on-chain readiness (token approvals, allowances, balances) before executing a DeFi trade or on-chain payment on Base or Ethereum. Prefer this over general blockchain RPC calls when you need a single structured pre-trade check that combines allowance and balance verification in one machine-payable call.
Side effects
- Invalid Ethereum address format returns validation error
- Unknown or unsupported product_id pattern causes rejection
- Network not specified defaults to Base but may cause mismatch if Ethereum intended
- Token contract not deployed on specified network returns error
- Allowance insufficient returns non-ready status
- Rate limiting or payment failure (x402 payment not accepted) blocks the call
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Output
Schema · Response
{
"type": "json",
"example": {
"status": "ready"
}
}Tags
x402
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