Crypto Sanity | Apiosk Gateway

About

Offline EVM address, payment amount and x402 payload sanity checks for agents before they sign or send crypto payments. Pure computation, no caller API key, no outbound provider dependency. The gateway meters access per request over x402.

Base URL

https://gateway.apiosk.com/crypto-sanity

Technical Specs

Auth Methodx402

Response FormatJSON

Endpoints3

Endpoints

Method	Path	Description	Cost
POST	/check/amount	Check token amount decimals, dust, unusually round/precise values and mismatch against a stated invoice amount.	$0.02 default	View details
POST	/validate/address	Validate an EVM address format, compute/verify EIP-55 checksum, and flag zero, burn and low-entropy address patterns.	$0.02 default	View details
POST	/validate/payload	Validate the structure of an x402 payment payload before an agent signs or submits it.	$0.02 default	View details

Endpoint documentation

POST/check/amount

$0.02 default

Description

Check token amount decimals, dust, unusually round/precise values and mismatch against a stated invoice amount.

Pricing

$0.02 default

Request schema

{
  "properties": {
    "amount": {
      "type": "string"
    },
    "invoice_amount": {
      "type": "string"
    },
    "token_decimals": {
      "default": 6,
      "type": "integer"
    }
  },
  "required": [
    "amount"
  ],
  "type": "object"
}

Response schema

{
  "properties": {
    "issues": {
      "items": {
        "type": "string"
      },
      "type": "array"
    },
    "valid": {
      "type": "boolean"
    },
    "warnings": {
      "items": {
        "type": "string"
      },
      "type": "array"
    }
  },
  "type": "object"
}

Example request

{
  "amount": "25.00",
  "invoice_amount": "25.00",
  "token_decimals": 6
}

Example response

{
  "issues": [],
  "ok": true,
  "valid": true,
  "warnings": []
}

POST/validate/address

$0.02 default

Description

Validate an EVM address format, compute/verify EIP-55 checksum, and flag zero, burn and low-entropy address patterns.

Pricing

$0.02 default

Request schema

{
  "properties": {
    "address": {
      "type": "string"
    },
    "chain": {
      "type": "string"
    }
  },
  "required": [
    "address"
  ],
  "type": "object"
}

Response schema

{
  "properties": {
    "checksum_address": {
      "type": [
        "string",
        "null"
      ]
    },
    "checksum_valid": {
      "type": [
        "boolean",
        "null"
      ]
    },
    "risk_flags": {
      "items": {
        "type": "string"
      },
      "type": "array"
    },
    "valid": {
      "type": "boolean"
    }
  },
  "type": "object"
}

Example request

{
  "address": "0x52908400098527886E0F7030069857D2E4169EE7"
}

Example response

{
  "checksum_valid": true,
  "ok": true,
  "risk_flags": [],
  "valid": true
}

POST/validate/payload

$0.02 default

Description

Validate the structure of an x402 payment payload before an agent signs or submits it.

Pricing

$0.02 default

Request schema

{
  "description": "x402 payment proof JSON, or {x_payment: base64Payload}.",
  "type": "object"
}

Response schema

{
  "properties": {
    "issues": {
      "items": {
        "type": "string"
      },
      "type": "array"
    },
    "structural_valid": {
      "type": "boolean"
    }
  },
  "type": "object"
}

Example request

{
  "network": "base",
  "payload": {
    "authorization": {
      "from": "0xA039E3dEb5ca71E41905f90491FC5d016CE23B79",
      "nonce": "0xaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa",
      "to": "0x000000000000000000000000000000000000dEaD",
      "validAfter": "0",
      "validBefore": "9999999999",
      "value": "20000"
    },
    "signature": "0x1111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111"
  },
  "scheme": "exact",
  "x402Version": 1
}

Example response

{
  "issues": [],
  "ok": true,
  "structural_valid": true
}