Blockchain Data · x402

Solidity ABI calldata encoder — encode canonical typed values for an EVM smart-contract…

Solidity ABI calldata encoder — encode canonical typed values for an EVM smart-contract function call, with an optional selector and exact 256-bit integers.

by chain-tools.use.x402atlas.com · discovered, not yet claimed by its owner · updated 2026-10-06

Mirrored from Coinbase's public x402 Bazaar. The description is the provider's own text and has not been reviewed here; the payment requirements are copied as published.

What it does

Solidity ABI calldata encoder — encode canonical typed values for an EVM smart-contract function call, with an optional selector and exact 256-bit integers.

Tags: abi-encode · solidity-abi · evm · blockchain-development · offline-computation · bazaar

Use with an agent

Discover. Agents find this listing with GET https://bazaar.saylorinnovations.com/discovery/search?query=…, the MCP tool search_resources, or /discovery/resources.
Inspect. Fetch /resources/28637.json for the price and payment options.
Pay. Call GET https://chain-tools.use.x402atlas.com/evm/abi-encode. The provider answers 402 with its payment requirements. An x402 client signs one of the options below and retries with PAYMENT-SIGNATURE.
Execute. The provider returns 200 with the data. Agent Bazaar is not in the request path and never sees your payment.

For humans

You don't need an account or an API key; you need a wallet holding a small amount of USDC on Base, Polygon, Arbitrum One, Solana, and an x402-capable client (see the examples below). Call the endpoint unpaid first to see exactly what it asks for.

Pricing & payment

Price: $0.005 / request
Protocol: x402 v2
Auth: No account or API key. Pay per request.
Networks: Base, Polygon, Arbitrum One, Solana
Calls (30d): 3 · 2 unique payers (third-party data from the public x402 Bazaar)

x402 payment requirements

Scheme	Network	Asset	Amount	Pay to	Timeout
exact	Base eip155:8453	USDC	$0.005	0x8C128f1Ee62Bb5e47867CfbAe2ad89be325Df1b2	300s
exact	Polygon eip155:137	USDC	$0.005	0x8C128f1Ee62Bb5e47867CfbAe2ad89be325Df1b2	300s
exact	Arbitrum One eip155:42161	USDC	$0.005	0x8C128f1Ee62Bb5e47867CfbAe2ad89be325Df1b2	300s
exact	Solana solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp	USDC	$0.005	ASt6xvRyQ7ntERsmcYVMdLqZvz1GEN8Fzexzq62tXrNQ	300s

accepts[] (raw JSON)

[
  {
    "scheme": "exact",
    "network": "eip155:8453",
    "payTo": "0x8C128f1Ee62Bb5e47867CfbAe2ad89be325Df1b2",
    "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
    "amount": "5000",
    "amountUsd": 0.005,
    "maxTimeoutSeconds": 300
  },
  {
    "scheme": "exact",
    "network": "eip155:137",
    "payTo": "0x8C128f1Ee62Bb5e47867CfbAe2ad89be325Df1b2",
    "asset": "0x3c499c542cEF5E3811e1192ce70d8cC03d5c3359",
    "amount": "5000",
    "amountUsd": 0.005,
    "maxTimeoutSeconds": 300
  },
  {
    "scheme": "exact",
    "network": "eip155:42161",
    "payTo": "0x8C128f1Ee62Bb5e47867CfbAe2ad89be325Df1b2",
    "asset": "0xaf88d065e77c8cC2239327C5EDb3A432268e5831",
    "amount": "5000",
    "amountUsd": 0.005,
    "maxTimeoutSeconds": 300
  },
  {
    "scheme": "exact",
    "network": "solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp",
    "payTo": "ASt6xvRyQ7ntERsmcYVMdLqZvz1GEN8Fzexzq62tXrNQ",
    "asset": "EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v",
    "amount": "5000",
    "amountUsd": 0.005,
    "maxTimeoutSeconds": 300
  }
]

Schemas

Output schema (JSON Schema)

{
  "properties": {
    "example": {
      "additionalProperties": false,
      "properties": {
        "_atlas": {
          "additionalProperties": false,
          "description": "Atlas documentation and related-route metadata added after deployment",
          "properties": {
            "docs": {
              "description": "Documentation URL for this bridge",
              "format": "uri",
              "maxLength": 512,
              "type": "string"
            },
            "related": {
              "description": "Bounded related Atlas routes",
              "items": {
                "additionalProperties": false,
                "description": "One related Atlas route",
                "properties": {
                  "bridge": {
                    "description": "Related bridge name",
                    "maxLength": 64,
                    "type": "string"
                  },
                  "docs": {
                    "description": "Related bridge documentation URL",
                    "format": "uri",
                    "maxLength": 512,
                    "type": "string"
                  },
                  "summary": {
                    "description": "Short capability summary",
                    "maxLength": 256,
                    "type": "string"
                  },
                  "url": {
                    "description": "Related route URL",
                    "format": "uri",
                    "maxLength": 512,
                    "type": "string"
                  }
                },
                "required": [
                  "bridge",
                  "url",
                  "docs",
                  "summary"
                ],
                "type": "object"
              },
              "maxItems": 3,
              "type": "array"
            }
          },
          "required": [
            "docs"
          ],
          "type": "object"
        },
        "algorithm_version": {
          "const": "solidity-abi-v1",
          "description": "Pinned Solidity ABI grammar and byte contract",
          "type": "string"
        },
        "data": {
          "description": "Complete encoded bytes, including selector when requested",
          "pattern": "^0x(?:[0-9a-f]{2})*$",
          "type": "string"
        },
        "function_signature": {
          "description": "Canonical signature when selector included",
          "type": "string"
        },
        "include_selector": {
          "description": "Whether data begins with selector",
          "type": "boolean"
        },
        "operation": {
          "const": "abi-encode",
          "description": "Stable route operation",
          "type": "string"
        },
        "payload": {
          "description": "Selector-free canonical ABI payload",
          "pattern": "^0x(?:[0-9a-f]{2})*$",
          "type": "string"
        },
        "selector": {
          "description": "Four-byte selector when included",
          "pattern": "^0x(?:[0-9a-f]{2})*$",
          "type": "string"
        },
        "types": {
          "description": "Canonical ABI types",
          "items": {
            "description": "Canonical Solidity ABI type",
            "type": "string"
          },
          "type": "array"
        },
        "values": {
          "description": "Normalized values in exact type order",
          "items": {
            "description": "Normalized exact JSON representation"
          },
          "type": "array"
        },
        "warnings": {
          "description": "Always empty for deterministic offline computation",
          "items": {
            "description": "Warning",
            "type": "string"
          },
          "maxItems": 0,
          "type": "array"
        }
      },
      "required": [
        "operation",
        "algorithm_version",
        "types",
        "values",
        "include_selector",
        "payload",
        "data",
        "warnings"
      ],
      "type": "object"
    },
    "type": {
      "type": "string"
    }
  },
  "required": [
    "type"
  ],
  "type": "object"
}

Example shape — generated from the schema, not a captured live response

{
  "example": {
    "_atlas": {
      "docs": "https://example.com",
      "related": [
        {
          "bridge": "string",
          "docs": "https://example.com",
          "summary": "string",
          "url": "https://example.com"
        }
      ]
    },
    "algorithm_version": "string",
    "data": "string",
    "function_signature": "string",
    "include_selector": true,
    "operation": "string",
    "payload": "string",
    "selector": "string",
    "types": [
      "string"
    ],
    "values": [
      "value"
    ],
    "warnings": [
      "string"
    ]
  },
  "type": "string"
}

Examples

curl

curl "https://chain-tools.use.x402atlas.com/evm/abi-encode"
# -> 402 Payment Required, accepts[] lists how to pay
# retry with a PAYMENT-SIGNATURE (or PAYMENT header) once paid

JavaScript

const res = await fetch("https://chain-tools.use.x402atlas.com/evm/abi-encode");
if (res.status === 402) {
  const { accepts } = await res.json();
  // pay one of accepts[] via an x402 client, then retry with the payment header
}

Python

import httpx
res = httpx.get("https://chain-tools.use.x402atlas.com/evm/abi-encode")
if res.status_code == 402:
    accepts = res.json()["accepts"]
    # pay one of accepts[] via an x402 client, then retry with the payment header

Details

Provider: chain-tools.use.x402atlas.com
Endpoint: https://chain-tools.use.x402atlas.com/evm/abi-encode
Machine-readable: /resources/28637.json