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Saylor Innovations ABI Encode Call
x402
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
Price / call$0.01
Success—
StatusUnknown
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.
Example use cases
Build raw ERC-20 transfer calldata
“I need to manually construct a raw Ethereum transaction to call transfer on an ERC-20 token. The function signature is transfer(address,uint256) and the args are ["0xAbCd1234abcd1234abcd1234abcd1234AbCd1234", "500000000000000000"]. Can you give me the full calldata and selector?”
Verify function selector matches expected
“What is the 4-byte selector for the function signature approve(address,uint256)? I want to double-check it matches 0x095ea7b3 before I send a transaction.”
Encode multicall payload offline
“I'm building a multicall batch and need calldata for swapExactTokensForTokens(uint256,uint256,address[],address,uint256) with args ["1000000","990000",["0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48","0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2"],"0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045","1700000000"]. Compute it locally without hitting any node.”
Technical details
Endpoint
GEThttps://saylorinnovations.com/api/chain/encode-call?utm_source=zero.xyzWhen to prefer
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.
Side effects
- 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
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Tags
x402
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