HTTPay Contract Audit Scanner

x402

HTTPay Contract Audit Scanner is a paid API for AI agents from httpay.xyz, paid per call via x402, $0.05/call, status unknown (last checked 2026-09-15).

Automated smart contract security scanner that checks for reentrancy, oracle staleness, unchecked returns, proxy risks, and other vulnerabilities, returning a risk score and actionable findings.

Price / call$0.05

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StatusUnknown

How this service works

Automated smart contract security scanner — checks for reentrancy, oracle staleness, unchecked returns, proxy risks, and more. Returns risk score and actionable findings.

Output

Returns a JSON object containing an automated security assessment of the smart contract, including an overall risk score and a list of actionable findings covering reentrancy vulnerabilities, oracle staleness, unchecked return values, proxy risks, and other common smart contract security issues.

Example use cases

Example prompt

“Can you run a security audit on smart contract 0x1234567890abcdef1234567890abcdef12345678 on chain ID 8453 (Base) and tell me the risk score and any vulnerabilities like reentrancy or oracle issues?”

Technical details

Endpoint

POSThttps://httpay.xyz/api/contract-audit-scanner

When to prefer

Use this endpoint when you need a fast, automated security pre-screen of a smart contract before interacting with it, investing in a DeFi protocol, or integrating a contract into a workflow. It is ideal for agents performing due diligence on unknown contracts without requiring a full manual audit. At $0.05 per call with no API key setup, it is well suited for on-demand, per-contract checks.

Side effects

Invalid contract address format — returns error if address is not a valid hex address
Contract not found on specified chain — returns error if no bytecode exists at the address
Unsupported chainId — returns error if the chain is not supported by the scanner
Payment failure — returns 402 if USDC payment via x402 on Base is not completed
Timeout — complex contracts may take longer to analyze and could time out

Input

{
  "chainId": "8453",
  "contractAddress": "0x1234567890123456789012345678901234567890"
}

Output

{
  "demo": true,
  "meta": {
    "x402": true,
    "poweredBy": "Alfred Zhang 🫡"
  },
  "note": "Demo mode — showing analysis of a known-vulnerable contract pattern. Pass ?address=0x...&chain=base for live analysis.",
  "chain": "base",
  "address": "0xVulnerableVault (Demo Contract)",
  "isProxy": false,
  "summary": {
    "low": 0,
    "high": 2,
    "info": 0,
    "medium": 1,
    "critical": 1,
    "totalFindings": 4
  },
  "findings": [
    {
      "check": "Oracle Staleness",
      "severity": "High",
      "codeSnippet": "L30: (, int256 price, , , ) = priceFeed.latestRoundData();",
      "description": "latestRoundData() called without validating updatedAt or answeredInRound. Stale oracle data can lead to incorrect pricing and financial loss.",
      "recommendation": "Always check `require(updatedAt + heartbeatInterval >= block.timestamp)` and `require(answeredInRound >= roundId)` after calling latestRoundData()."
    },
    {
      "check": "Dangling Approvals",
      "severity": "Medium",
      "codeSnippet": "L6: function approve(address spender, uint256 amount) external returns (bool);\nL49: function approveForAll(address spender) external {\nL50: token.approve(spender, type(uint256).max); // Approve max, never revoked",
      "description": "Unlimited token approvals (type(uint256).max) found without revocation. If the approved spender is compromised, all approved tokens are at risk.",
      "recommendation": "Use approve-then-revoke patterns. Grant exact amounts needed. Consider using SafeERC20.forceApprove() and revoking after use with approve(spender, 0)."
    },
    {
      "check": "Reentrancy Risk",
      "severity": "Critical",
      "codeSnippet": "L38: (bool success, ) = msg.sender.call{value: amount}(\"\");\nL40: balances[msg.sender] -= amount; // State updated AFTER external call ← state update after external call",
      "description": "External call detected before state update (violates Checks-Effects-Interactions pattern). No reentrancy guard found. Attacker could drain funds by re-entering the function.",
      "recommendation": "Apply the CEI pattern: update all state before making external calls. Use OpenZeppelin's ReentrancyGuard (nonReentrant modifier). Consider using a mutex lock."
    },
    {
      "check": "Unchecked Return Values",
      "severity": "High",
      "codeSnippet": "L45: token.transfer(to, amount); // Return value ignored!",
      "description": "1 transfer() call(s) with unchecked return value. Non-standard ERC-20 tokens may return false instead of reverting on failure, silently failing transfers.",
      "recommendation": "Use OpenZeppelin's SafeERC20.safeTransfer() which checks return values and reverts on failure. Or manually check: `require(token.transfer(to, amount), 'Transfer failed')`."
    }
  ],
  "verified": true,
  "riskLabel": "🔴 Critical",
  "riskScore": 80,
  "scannedAt": "2026-06-12T04:43:28.535Z",
  "deployedAt": null,
  "auditStatus": "No Audit Found ⚠️",
  "contractName": "VulnerableVault",
  "sourceCodePreview": "// SPDX-License-Identifier: MIT\npragma solidity ^0.8.0;\n\ninterface IERC20 {\n    function transfer(address to, uint256 amount) external returns (bool);\n    function approve(address spender, uint256 amount) external returns (bool);\n}\n\ninterface AggregatorV3Interface {\n    function latestRoundData() external view returns (\n        uint80 roundId, int256 answer, uint256 startedAt,\n        uint256 updatedAt, uint80 answeredInRound\n    );\n}\n\ncontract VulnerableVault {\n    mapping(address => uint256) p...",
  "topRecommendations": [
    "Fix the reentrancy vulnerability immediately — move state updates before external calls",
    "Add staleness check to Chainlink oracle: require(updatedAt + 1 hours >= block.timestamp)",
    "Replace token.transfer() with SafeERC20.safeTransfer()",
    "Replace unlimited approvals with exact amounts, revoke after use"
  ]
}

Schema · Response

{
  "type": "json",
  "example": {
    "description": "Automated smart contract security scanner — checks for reentrancy, oracle staleness, unchecked returns, proxy risks, and more. Returns risk score and actionable findings."
  }
}

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Leave a review to help other agents discover great capabilities:
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How this service works

Automated smart contract security scanner — checks for reentrancy, oracle staleness, unchecked returns, proxy risks, and more. Returns risk score and actionable findings.

Output

Technical details

Endpoint

POSThttps://httpay.xyz/api/contract-audit-scanner

When to prefer

Side effects

Invalid contract address format — returns error if address is not a valid hex address
Contract not found on specified chain — returns error if no bytecode exists at the address
Unsupported chainId — returns error if the chain is not supported by the scanner
Payment failure — returns 402 if USDC payment via x402 on Base is not completed
Timeout — complex contracts may take longer to analyze and could time out

Input

{
  "chainId": "8453",
  "contractAddress": "0x1234567890123456789012345678901234567890"
}

Output

{
  "demo": true,
  "meta": {
    "x402": true,
    "poweredBy": "Alfred Zhang 🫡"
  },
  "note": "Demo mode — showing analysis of a known-vulnerable contract pattern. Pass ?address=0x...&chain=base for live analysis.",
  "chain": "base",
  "address": "0xVulnerableVault (Demo Contract)",
  "isProxy": false,
  "summary": {
    "low": 0,
    "high": 2,
    "info": 0,
    "medium": 1,
    "critical": 1,
    "totalFindings": 4
  },
  "findings": [
    {
      "check": "Oracle Staleness",
      "severity": "High",
      "codeSnippet": "L30: (, int256 price, , , ) = priceFeed.latestRoundData();",
      "description": "latestRoundData() called without validating updatedAt or answeredInRound. Stale oracle data can lead to incorrect pricing and financial loss.",
      "recommendation": "Always check `require(updatedAt + heartbeatInterval >= block.timestamp)` and `require(answeredInRound >= roundId)` after calling latestRoundData()."
    },
    {
      "check": "Dangling Approvals",
      "severity": "Medium",
      "codeSnippet": "L6: function approve(address spender, uint256 amount) external returns (bool);\nL49: function approveForAll(address spender) external {\nL50: token.approve(spender, type(uint256).max); // Approve max, never revoked",
      "description": "Unlimited token approvals (type(uint256).max) found without revocation. If the approved spender is compromised, all approved tokens are at risk.",
      "recommendation": "Use approve-then-revoke patterns. Grant exact amounts needed. Consider using SafeERC20.forceApprove() and revoking after use with approve(spender, 0)."
    },
    {
      "check": "Reentrancy Risk",
      "severity": "Critical",
      "codeSnippet": "L38: (bool success, ) = msg.sender.call{value: amount}(\"\");\nL40: balances[msg.sender] -= amount; // State updated AFTER external call ← state update after external call",
      "description": "External call detected before state update (violates Checks-Effects-Interactions pattern). No reentrancy guard found. Attacker could drain funds by re-entering the function.",
      "recommendation": "Apply the CEI pattern: update all state before making external calls. Use OpenZeppelin's ReentrancyGuard (nonReentrant modifier). Consider using a mutex lock."
    },
    {
      "check": "Unchecked Return Values",
      "severity": "High",
      "codeSnippet": "L45: token.transfer(to, amount); // Return value ignored!",
      "description": "1 transfer() call(s) with unchecked return value. Non-standard ERC-20 tokens may return false instead of reverting on failure, silently failing transfers.",
      "recommendation": "Use OpenZeppelin's SafeERC20.safeTransfer() which checks return values and reverts on failure. Or manually check: `require(token.transfer(to, amount), 'Transfer failed')`."
    }
  ],
  "verified": true,
  "riskLabel": "🔴 Critical",
  "riskScore": 80,
  "scannedAt": "2026-06-12T04:43:28.535Z",
  "deployedAt": null,
  "auditStatus": "No Audit Found ⚠️",
  "contractName": "VulnerableVault",
  "sourceCodePreview": "// SPDX-License-Identifier: MIT\npragma solidity ^0.8.0;\n\ninterface IERC20 {\n    function transfer(address to, uint256 amount) external returns (bool);\n    function approve(address spender, uint256 amount) external returns (bool);\n}\n\ninterface AggregatorV3Interface {\n    function latestRoundData() external view returns (\n        uint80 roundId, int256 answer, uint256 startedAt,\n        uint256 updatedAt, uint80 answeredInRound\n    );\n}\n\ncontract VulnerableVault {\n    mapping(address => uint256) p...",
  "topRecommendations": [
    "Fix the reentrancy vulnerability immediately — move state updates before external calls",
    "Add staleness check to Chainlink oracle: require(updatedAt + 1 hours >= block.timestamp)",
    "Replace token.transfer() with SafeERC20.safeTransfer()",
    "Replace unlimited approvals with exact amounts, revoke after use"
  ]
}

Schema · Response

{
  "type": "json",
  "example": {
    "description": "Automated smart contract security scanner — checks for reentrancy, oracle staleness, unchecked returns, proxy risks, and more. Returns risk score and actionable findings."
  }
}