# Delx Commerce EVM Calldata Selector Extract

> Delx Commerce EVM Calldata Selector Extract is a paid API for AI agents from commerce.delx.ai, paid per call via x402, $0.001/call, status unknown (last checked 2026-10-01).

Extracts the 4-byte function selector from raw EVM calldata and validates its basic structure

## Facts

- Endpoint: POST https://commerce.delx.ai/api/v1/x402/evm-calldata-selector-extract?utm_source=zero.xyz
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-01
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/delx-commerce-evm-calldata-selector-extract-80442095
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_MH1bo5-aKUmpprNh_avRE

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 delx-commerce-evm-calldata-selector-extract-80442095 -d '<json body>'
```

Example prompt: Can you extract the 4-byte function selector from this EVM calldata and tell me if it's valid: 0xa9059cbb0000000000000000000000001111111111111111111111111111111111111111?

## When to prefer this

Choose this endpoint when you need a fast, verifiable, privacy-preserving way to extract the function selector from EVM calldata without setting up local ABI parsing infrastructure. It is ideal for agent workflows that need to preflight or audit transaction calldata before submission, especially when verifiable evidence (SHA256, no-retention proof, zero external calls) is required for audit trails. It costs only $0.001 USDC per call, requires no signup, and supports x402 micropayment flows natively.

## Known failure modes

- Malformed or non-hex calldata string causes validation failure
- Calldata exceeding 8192 character limit is rejected
- Empty calldata input returns shape_valid: false
- Missing required calldata field returns a 4xx error
- Payment not included or insufficient USDC causes HTTP 402 response

## How this service works

Pay-per-result APIs for agents. No signup. Exact price. Verifiable delivery. USDC on Base + Solana via x402.

## Output

Returns a JSON object with the extracted 4-byte function selector, total byte count of the calldata, a boolean indicating whether the calldata shape is valid, and an evidence block including whether input was retained (always false), the SHA256 hash of the input for verifiability, and the count of external calls made (always 0).

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "calldata": {
   "type": "string",
   "maxLength": 8192,
   "description": "Calldata supplied to EVM Calldata Selector Extract; used only for this bounded calculation and processed in memory without retention."
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "result": {
   "calldata": "0xa9059cbb0000000000000000000000001111111111111111111111111111111111111111",
   "selector": "0xa9059cbb",
   "byte_count": 36,
   "shape_valid": true
  },
  "schema": "delx/util-evm-calldata-selector-extract/v1",
  "status": "pass",
  "evidence": {
   "retained": false,
   "input_sha256": "1048e8d74a53c6ea3249086735deac2cb24ee3dd131a3852df0439253301d8de",
   "external_calls": 0
  },
  "operation": "evm_preflight:evm_calldata_selector_extract"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/delx-commerce-evm-calldata-selector-extract-80442095/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from commerce.delx.ai](https://www.zero.xyz/host/commerce.delx.ai/llms.txt)