# Saylor Innovations ABI Encode Call

> Saylor Innovations ABI Encode Call is a paid API for AI agents from saylorinnovations.com, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-27).

Encodes an EVM contract function call into ABI calldata and returns the 4-byte selector, computed locally without a node

## Facts

- Endpoint: GET https://saylorinnovations.com/api/chain/encode-call?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-27
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/saylor-innovations-abi-encode-call-e75d6e23
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_viPxCfq_NfW_JpX74CVpi

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 saylor-innovations-abi-encode-call-e75d6e23
```

Example prompt: Can you encode a contract call for the ERC-20 transfer function — signature is transfer(address,uint256) and the arguments are ["0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045", "1000000"] — I need the calldata and the 4-byte selector?

## When to prefer this

Choose this endpoint when you need to ABI-encode a contract call offline — without connecting to an Ethereum node or RPC provider — and want both the 4-byte selector and full calldata in one call. Ideal for constructing raw transactions, building multicall payloads, or verifying selectors without any web3 library dependency. Prefer over on-chain methods when speed and statelessness matter.

## Known failure modes

- Invalid or malformed function signature returns an error (e.g. missing parentheses or unsupported type)
- Mismatched argument count vs signature types causes encoding failure
- Malformed JSON array in args parameter causes parse error
- Unsupported ABI types (e.g. custom structs without tuple notation) may fail to encode
- Arguments with wrong types (e.g. string where uint256 expected) return encoding errors

## How this service works

Encode a contract call: give a function signature and a JSON array of arguments, get calldata and the 4-byte selector. Computed locally, no node needed.

## Output

Returns a JSON object containing the original function signature, the 4-byte selector (hex), the full ABI-encoded calldata (selector + encoded arguments), the calldata length in bytes, the parsed argument types array, a plain-language note explaining the result, and a source field describing how the data was computed locally.

## 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"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "signature",
      "args"
     ],
     "properties": {
      "args": {
       "type": "string",
       "description": "the arguments as a JSON array, for example [\"0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045\",\"1000000\"]"
      },
      "signature": {
       "type": "string",
       "description": "the function signature with types only, for example transfer(address,uint256)"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "json"
    },
    "example": {
     "type": "object",
     "required": [
      "signature",
      "selector",
      "calldata",
      "calldata_bytes",
      "note",
      "source"
     ],
     "properties": {
      "note": {
       "type": "string",
       "description": "plain-language reading of the result"
      },
      "source": {
       "type": "string",
       "description": "where the data was read from or how it was computed"
      },
      "calldata": {
       "type": "string",
       "description": "selector plus ABI-encoded arguments"
      },
      "selector": {
       "type": "string",
       "description": "4-byte function selector"
      },
      "signature": {
       "type": "string",
       "description": "the signature that was encoded"
      },
      "argument_types": {
       "type": [
        "array",
        "null"
       ],
       "description": "types parsed from the signature"
      },
      "calldata_bytes": {
       "type": "number",
       "description": "length of the calldata"
      }
     }
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/saylor-innovations-abi-encode-call-e75d6e23/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from saylorinnovations.com](https://www.zero.xyz/host/saylorinnovations.com/llms.txt)