# X402 Refund Amount Check

> X402 Refund Amount Check is a paid API for AI agents from api.delx.ai, paid per call via x402, $0.001/call, status unknown (last checked 2026-10-21).

Validates that a requested refund raw amount does not exceed the original settled raw amount for an x402 transaction, returning an explicit acceptance or rejection with mismatch reasons.

## Facts

- Endpoint: POST https://api.delx.ai/api/v1/x402/x402-refund-amount-check?utm_source=zero.xyz
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-21
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/x402-refund-amount-check-25f59228
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_ep6W0Pf4t6cFKCf8GcumU

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 x402-refund-amount-check-25f59228 -d '<json body>'
```

Example prompt: Before processing this refund, check if the requested raw amount of 1000000 is valid against the original settled raw amount of 1500000 for this x402 transaction.

## When to prefer this

Use this endpoint when you need to validate x402 refund requests before processing or accepting them, specifically to ensure a requested refund does not exceed the original settled amount. Prefer this over manual comparisons when working within x402 or agent delivery workflows where auditability and explicit rejection reasons are required.

## Known failure modes

- Missing or malformed settled_raw or requested_raw inputs returns an error
- Non-numeric string values in either field may cause computation failure
- Values exceeding maxLength of 8192 characters are rejected
- Ambiguous or empty strings may produce indeterminate validation results

## How this service works

X402 Refund Amount Check: X402 Refund Amount Check compares requested refund raw amount with original settled amount from bounded caller-supplied values without an external provider. Call X402 Refund Amount Check before paying for or accepting an x402 or agent delivery assembled from caller-supplied challenge and result metadata. Returns contract-specific checks, normalized evidence, mismatch reasons, and an explicit acceptance or rejection status for X402 Refund Amount Check as versioned deter…

## Output

Returns an explicit acceptance or rejection status for the refund, along with normalized evidence of the comparison, contract-specific validation checks, and detailed mismatch reasons if the requested refund amount exceeds the settled amount.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "settled_raw": {
   "type": "string",
   "maxLength": 8192,
   "description": "Settled Raw supplied to X402 Refund Amount Check; used only for this bounded calculation and processed in memory without retention."
  },
  "requested_raw": {
   "type": "string",
   "maxLength": 8192,
   "description": "Requested Raw supplied to X402 Refund Amount Check; used only for this bounded calculation and processed in memory without retention."
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "result": {
   "drift_raw": "0",
   "actual_raw": "1000",
   "expected_raw": "1000",
   "within_tolerance": true
  },
  "schema": "delx/util-x402-refund-amount-check/v1",
  "status": "pass",
  "evidence": {
   "retained": false,
   "input_sha256": "8f2b3a0b094ceb2d8c75d4ce4b7f179347769e2b9645666d7c973aae510291f0",
   "external_calls": 0
  },
  "operation": "delivery_contract:x402_refund_amount_check"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/x402-refund-amount-check-25f59228/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.delx.ai](https://www.zero.xyz/host/api.delx.ai/llms.txt)