# X402 Refund Deadline Check

> X402 Refund Deadline 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).

Checks whether a refund request timestamp falls within a policy window, returning acceptance or rejection status with mismatch reasons

## Facts

- Endpoint: POST https://api.delx.ai/api/v1/x402/x402-refund-deadline-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-deadline-check-c23d4e27
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_ucTkQ855V-xg5BWqDDAX5

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-deadline-check-c23d4e27 -d '<json body>'
```

Example prompt: Before accepting this x402 refund request, check whether it falls within the allowed window: the payment settled at epoch 1718000000, the refund was requested at epoch 1718003600, and the policy window is 7200 seconds — is it still eligible?

## When to prefer this

Use this endpoint when you need a lightweight, deterministic, in-memory check of whether a refund request timestamp falls within a caller-defined policy window — especially in x402 payment or agent delivery flows where no external oracle or blockchain lookup is needed. Prefer it over custom logic when you want a normalized, versioned verdict with explicit mismatch reasons rather than writing your own timestamp arithmetic.

## Known failure modes

- Missing required fields (window_seconds, settled_at_epoch, or requested_at_epoch) result in a validation error
- Negative or zero window_seconds may produce unexpected results or an error
- Non-integer epoch values cause schema validation failures
- requested_at_epoch earlier than settled_at_epoch may be flagged as logically invalid
- Network timeout or service unavailability returns a 5xx error

## How this service works

X402 Refund Deadline Check: X402 Refund Deadline Check checks a refund request timestamp against a policy window from bounded caller-supplied values without an external provider. Call X402 Refund Deadline 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 Deadline Check as versioned deter…

## Output

Returns a structured verdict including: an explicit accept or reject status, normalized evidence about the timestamps, computed time difference versus the policy window, and mismatch reasons explaining why the request was rejected if applicable — all as versioned deterministic output.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "window_seconds": {
   "type": "integer",
   "description": "Window Seconds supplied to X402 Refund Deadline Check; used only for this bounded calculation and processed in memory without retention."
  },
  "settled_at_epoch": {
   "type": "integer",
   "description": "Settled At Epoch supplied to X402 Refund Deadline Check; used only for this bounded calculation and processed in memory without retention."
  },
  "requested_at_epoch": {
   "type": "integer",
   "description": "Requested At Epoch supplied to X402 Refund Deadline Check; used only for this bounded calculation and processed in memory without retention."
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "result": {
   "within_window": true,
   "elapsed_seconds": 3600
  },
  "schema": "delx/util-x402-refund-deadline-check/v1",
  "status": "pass",
  "evidence": {
   "retained": false,
   "input_sha256": "75b029c9b2e724be9e810d27a39f2fd8a936b5f84bafd8c79078d3272448753c",
   "external_calls": 0
  },
  "operation": "delivery_contract:x402_refund_deadline_check"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/x402-refund-deadline-check-c23d4e27/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)