# Delx Commerce — EVM Nonce Replace Check

> Delx Commerce — EVM Nonce Replace Check 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).

Checks whether a proposed EVM transaction nonce targets any pending (stuck) nonces, enabling safe nonce replacement decisions before transaction submission.

## Facts

- Endpoint: POST https://commerce.delx.ai/api/v1/x402/evm-nonce-replace-check?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-nonce-replace-check-a0b6ff7b
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_aMRrbvL909UmZPqLBa04o

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-nonce-replace-check-a0b6ff7b -d '<json body>'
```

Example prompt: Check if proposed nonce 11 would replace any of my pending EVM transactions with nonces [8, 9, 10] — I want to know if it's safe to use before I broadcast a replacement.

## When to prefer this

Use this endpoint when an AI agent or wallet automation system needs to perform a zero-knowledge, verifiable preflight check before broadcasting a nonce-replacement EVM transaction. It is ideal when you need cryptographic evidence (SHA256 of inputs) that the check was performed without data retention or external calls — useful in auditable, trust-minimized agent pipelines. Prefer this over on-chain lookups when you need a fast, cheap ($0.001 USDC), off-chain computation with verifiable delivery guarantees via x402.

## Known failure modes

- Input array exceeds 256 items (maxItems constraint violated)
- Non-integer nonce values cause schema validation failure
- Missing required fields result in 400 Bad Request
- Payment not included or insufficient USDC results in 402 Payment Required
- Network timeout if Base or Solana payment rails are congested

## 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 containing the proposed nonce value, a boolean flag indicating whether it targets any pending nonce (targets_pending), a status field ('pass'), and an evidence object with a SHA256 hash of the inputs and confirmation that no data was retained and no external calls were made.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "pending_nonces": {
   "type": "array",
   "items": {
    "type": "integer"
   },
   "maxItems": 256,
   "description": "Pending Nonces supplied to EVM Nonce Replace Check; used only for this bounded calculation and processed in memory without retention."
  },
  "proposed_nonce": {
   "type": "integer",
   "description": "Proposed Nonce supplied to EVM Nonce Replace Check; used only for this bounded calculation and processed in memory without retention."
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "result": {
   "proposed_nonce": 11,
   "targets_pending": true
  },
  "schema": "delx/util-evm-nonce-replace-check/v1",
  "status": "pass",
  "evidence": {
   "retained": false,
   "input_sha256": "a3ab4cbc105327ec6bf99174fcfd83de2a8605ff927d8cd849aed39cba23d03e",
   "external_calls": 0
  },
  "operation": "evm_preflight:evm_nonce_replace_check"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/delx-commerce-evm-nonce-replace-check-a0b6ff7b/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)