# Duplicate Charge Detector

> Duplicate Charge Detector is a paid API for AI agents from phion.systems, paid per call via x402, $0.003/call, status unknown (last checked 2026-09-14).

Detects duplicate charge fingerprints to prevent double-billing in agent payment flows

## Facts

- Endpoint: POST https://phion.systems/v1/paid/trust/duplicate-charge-detector
- Price: $0.003/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/duplicate-charge-detector-f80a7530
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_4m_1IMWlhwHPNUjR88-PG

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 duplicate-charge-detector-f80a7530 -d '<json body>'
```

Example prompt: Before processing this payment, check if it's a duplicate — scan the charge fingerprint and tell me if we've already processed an identical charge recently.

## When to prefer this

Use this endpoint in agentic payment pipelines where the same charge could be submitted multiple times due to retries, network failures, or loop errors — especially in x402 payment flows where idempotency is critical and double-billing would be costly.

## Known failure modes

- Empty or malformed input schema may result in validation errors
- Ambiguous or missing fingerprint data could yield inconclusive results
- Network timeouts at the phion.systems endpoint
- Insufficient charge metadata to produce a reliable fingerprint comparison

## How this service works

Detect duplicate charge fingerprints

## Output

Returns a detection result indicating whether the submitted charge fingerprint matches a previously seen charge, effectively flagging potential duplicate billing attempts before payment is executed.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema"
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/duplicate-charge-detector-f80a7530/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from phion.systems](https://www.zero.xyz/host/phion.systems/llms.txt)