# Delx Commerce — DNS MX Priority Sort

> Delx Commerce — DNS MX Priority Sort is a paid API for AI agents from commerce.delx.ai, paid per call via x402, $0.001/call, status unknown (last checked 2026-10-02).

Sorts an array of DNS MX records by their priority values in ascending order, returning them ranked from highest to lowest preference.

## Facts

- Endpoint: POST https://commerce.delx.ai/api/v1/x402/dns-mx-priority-sort?utm_source=zero.xyz
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-02
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/delx-commerce-dns-mx-priority-sort-0a4b2d18
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_0JpJlClFcztGZ7yBN84TP

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 delx-commerce-dns-mx-priority-sort-0a4b2d18 -d '<json body>'
```

Example prompt: Sort these MX records by priority for me: [{"exchange":"mx1.example.com","priority":20},{"exchange":"mx2.example.com","priority":10}] — I need them ordered from most to least preferred so I know which mail server to try first.

## When to prefer this

Choose this endpoint when you need a fast, cheap, verifiable, stateless sort of DNS MX records with cryptographic evidence of non-retention — ideal for AI agents in email infrastructure workflows that require auditability and pay-per-use pricing without signup overhead.

## Known failure modes

- Empty or missing 'records' array returns zero-count result
- Records exceeding 256 items may be rejected (maxItems constraint)
- Individual record objects exceeding 128 properties may be rejected (maxProperties constraint)
- Malformed JSON input returns error response
- Payment failure (x402) blocks execution before processing

## How this service works

Pay-per-result APIs for agents. No signup. Exact price. Verifiable delivery. USDC on Base + Solana via x402.

## Output

Returns a JSON object with a sorted array of MX records (each containing 'exchange' and 'priority' fields), a count of records, status ('pass'), the operation name, and an evidence block confirming no external calls were made and no input data was retained (includes input SHA-256 hash for verifiability).

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "records": {
   "type": "array",
   "items": {
    "type": "object",
    "maxProperties": 128,
    "additionalProperties": true
   },
   "maxItems": 256,
   "description": "Records supplied to DNS MX Priority Sort; used only for this bounded calculation and processed in memory without retention."
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "result": {
   "count": 2,
   "records": [
    {
     "exchange": "mx1.example.com",
     "priority": 10
    },
    {
     "exchange": "mx2.example.com",
     "priority": 20
    }
   ]
  },
  "schema": "delx/util-dns-mx-priority-sort/v1",
  "status": "pass",
  "evidence": {
   "retained": false,
   "input_sha256": "8b3539e1e41d77579f810b455d097216ad210c5fa90b58563e75aef928e5684a",
   "external_calls": 0
  },
  "operation": "web_reliability:dns_mx_priority_sort"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/delx-commerce-dns-mx-priority-sort-0a4b2d18/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from commerce.delx.ai](https://www.zero.xyz/host/commerce.delx.ai/llms.txt)