# X402 Delivery Latency Check

> X402 Delivery Latency Check is a paid API for AI agents from api.delx.ai, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-15).

Validates observed delivery latency against a buyer-defined SLA threshold and returns an explicit accept/reject status with mismatch reasons

## Facts

- Endpoint: POST https://api.delx.ai/api/v1/x402/x402-delivery-latency-check
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/x402-delivery-latency-check-264a3ad3
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_vcQTDAhQMYLyceHPIi8uc

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-delivery-latency-check-264a3ad3 -d '<json body>'
```

Example prompt: Before I accept this delivery, check if the observed latency of 320 ms is within my maximum allowed threshold of 500 ms and tell me whether to accept or reject it.

## When to prefer this

Use this endpoint when you need a deterministic, bounded, in-memory latency SLA check without relying on any external data provider — specifically before accepting or paying for an x402 or agent delivery where delivery speed is a contractual requirement. Prefer this over custom code when you need versioned, auditable accept/reject evidence with normalized mismatch reasons for dispute resolution or automated pipeline gating.

## Known failure modes

- Missing required fields (latency_ms or maximum_ms not provided) resulting in a validation error
- Non-integer or negative values for latency_ms or maximum_ms causing input rejection
- Maximum_ms set to zero causing division or comparison edge-case errors
- Network timeout reaching the validation endpoint itself

## How this service works

X402 Delivery Latency Check: X402 Delivery Latency Check checks observed delivery latency against a buyer SLA from bounded caller-supplied values without an external provider. Call X402 Delivery Latency 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 Delivery Latency Check as versioned determ…

## Output

Returns a versioned, deterministic validation result including an explicit accept or reject status, contract-specific check outcomes, normalized evidence of the latency comparison, and human-readable mismatch reasons explaining why the delivery passed or failed the SLA threshold.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "latency_ms": {
   "type": "integer",
   "description": "Latency Ms supplied to X402 Delivery Latency Check; used only for this bounded calculation and processed in memory without retention."
  },
  "maximum_ms": {
   "type": "integer",
   "description": "Maximum Ms supplied to X402 Delivery Latency Check; used only for this bounded calculation and processed in memory without retention."
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "result": {
   "latency_ms": 120,
   "maximum_ms": 1000,
   "within_sla": true
  },
  "schema": "delx/util-x402-delivery-latency-check/v1",
  "status": "pass",
  "evidence": {
   "retained": false,
   "input_sha256": "03c9c90cd7fb858eb54622ab93888c5358b1c9a17f5cf97704f3515687d97231",
   "external_calls": 0
  },
  "operation": "delivery_contract:x402_delivery_latency_check"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/x402-delivery-latency-check-264a3ad3/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)