# Polygon Nonce Replacement Analyzer

> Polygon Nonce Replacement Analyzer is a paid API for AI agents from signalharness.ai, paid per call via x402, $0.015/call, status unknown (last checked 2026-09-13).

Analyzes Polygon PoS transaction sets to detect nonce gaps, replacement groups, and ordering anomalies from caller-supplied transaction data.

## Facts

- Endpoint: POST https://signalharness.ai/api/agent/services/polygon_nonce_replacement_analyze/invoke
- Price: $0.015/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-13
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/polygon-nonce-replacement-analyzer-c874bf7c
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_WlxFpq6jeMegFmG24cs9g

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 polygon-nonce-replacement-analyzer-c874bf7c -d '<json body>'
```

Example prompt: Analyze these Polygon transactions for nonce gaps or replacement groups — here's the raw transaction data as JSON: [{"from":"0xABC...","hash":"0x111...","nonce":"5","max_fee_per_gas":"120"},{"from":"0xABC...","hash":"0x222...","nonce":"5","max_fee_per_gas":"150"}]. Tell me if any are replacements of each other.

## When to prefer this

Use this endpoint when you have raw Polygon PoS transaction data (mainnet chain ID 137 or testnet 80002) and need to programmatically detect nonce gaps, identify replacement/speedup transaction pairs, or audit sequencing issues — all from caller-supplied data without requiring live RPC access. Prefer this over manual nonce inspection when processing batches of transactions or building agent workflows that need to classify stuck, dropped, or replaced Polygon transactions.

## Known failure modes

- Malformed or non-JSON request_json input returns a parse error
- Transactions from unsupported chain IDs (not 137 or 80002) may not be analyzed correctly
- Replacement status is never inferred without externally supplied evidence — warnings will be returned
- Empty transaction arrays return an analysis with no gaps or replacement groups detected
- Overly large inputs exceeding 65536 characters will be rejected

## How this service works

Explore 330 pay-per-call x402 API services and 27 agent-native digital products, with Base USDC pricing, secure Polar checkout, and free discovery.

## Output

Returns a structured analysis JSON containing identified nonce gaps (missing nonces in sequence), replacement groups (transactions sharing a nonce from the same sender), per-transaction metadata with index and gas fields, network context (accepted chain IDs, bridge model, protocol family), evidence scope label, analyzed network name, and any warnings such as inability to infer canonical replacement status without additional evidence.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "request_json": {
   "type": "string",
   "maxLength": 65536,
   "minLength": 2
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "replay": false,
  "result": {
   "warnings": [
    "Canonical replacement status is not inferred."
   ],
   "service_id": "polygon_nonce_replacement_analyze",
   "analysis_json": "{\"network_context\":{\"accepted_chain_ids\":[\"137\",\"80002\"],\"bridge_model\":\"root-child state sync plus checkpoint evidence\",\"completion_policy\":\"never inferred without supplied evidence\",\"protocol_family\":\"Polygon PoS\"},\"nonce_gaps\":[],\"replacement_groups\":[],\"transactions\":[{\"from\":\"0x0000000000000000000000000000000000000001\",\"hash\":\"0x1111111111111111111111111111111111111111111111111111111111111111\",\"index\":0,\"max_fee_per_gas\":\"120\",\"nonce\":\"1\"}]}",
   "evidence_scope": "caller_supplied_data",
   "analyzed_network": "polygon"
  },
  "status": "succeeded",
  "receipt": {
   "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
   "usage": [],
   "status": "succeeded",
   "network": "eip155:8453",
   "artifacts": [],
   "endedAtMs": 0,
   "latencyMs": 0,
   "paymentId": "example-payment",
   "receiptId": "example-receipt",
   "requestId": "example-request",
   "serviceId": "polygon_nonce_replacement_analyze",
   "executionId": "example-execution",
   "startedAtMs": 0,
   "amountAtomic": "15000",
   "resultSha256": "457aaa5e3cbbcf2ca40ed3ba06837462537b0ff07ee18087a8f7a548f18e33eb",
   "serviceVersion": "1.0.0",
   "settlementReference": "0x0000000000000000000000000000000000000000000000000000000000000000"
  },
  "artifacts": [],
  "requestId": "example-request",
  "executionId": "example-execution"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/polygon-nonce-replacement-analyzer-c874bf7c/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from signalharness.ai](https://www.zero.xyz/host/signalharness.ai/llms.txt)