# DNS SOA Serial Compare

> DNS SOA Serial Compare 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).

Compares two DNS SOA serial numbers using RFC 1982 32-bit wraparound ordering to determine which is newer or equal

## Facts

- Endpoint: POST https://api.delx.ai/api/v1/x402/dns-soa-serial-compare
- 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/dns-soa-serial-compare-0e470b77
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_PDIFBstyw46rNIR9kzhgs

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 dns-soa-serial-compare-0e470b77 -d '<json body>'
```

Example prompt: Compare DNS SOA serial 2023010101 (current) against candidate serial 2023010102 and tell me if the candidate is newer using RFC 1982 32-bit wraparound ordering.

## When to prefer this

Use this endpoint when you need a stateless, deterministic, RFC 1982-compliant comparison of DNS SOA serials that correctly handles 32-bit wraparound — particularly when current or candidate serials are near the 2^32 boundary where naive integer comparison would give wrong results. Prefer over custom code when you need an auditable, versioned, pay-per-use computation with no server-side state retention.

## Known failure modes

- Missing or invalid integer inputs return an error response
- Values outside 32-bit unsigned integer range may produce unexpected results
- Ambiguous zone (difference exactly 2^31) returns advisory rather than definitive result

## How this service works

DNS SOA Serial Compare: DNS SOA Serial Compare compares SOA serials with 32-bit wraparound ordering from bounded caller-supplied values without an external provider. Call DNS SOA Serial Compare before accepting, caching, redirecting, or retrying a caller-supplied web response. Returns normalized web evidence, the computed finding, and an explicit pass or advisory status for DNS SOA Serial Compare as versioned deterministic JSON. Price: $0.001 USDC via x402 on Base. First-party, stateless, memor…

## Output

Returns a versioned deterministic JSON object containing: normalized evidence of the two input serials, the computed comparison finding (whether candidate is newer, equal, or older than current under RFC 1982 32-bit modular arithmetic), and an explicit pass or advisory status indicating whether the candidate serial should be accepted.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "current": {
   "type": "integer",
   "description": "Current supplied to DNS SOA Serial Compare; used only for this bounded calculation and processed in memory without retention."
  },
  "candidate": {
   "type": "integer",
   "description": "Candidate supplied to DNS SOA Serial Compare; used only for this bounded calculation and processed in memory without retention."
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "result": {
   "current": 2026080901,
   "candidate": 2026080902,
   "delta_mod_32": 1,
   "candidate_newer": true
  },
  "schema": "delx/util-dns-soa-serial-compare/v1",
  "status": "pass",
  "evidence": {
   "retained": false,
   "input_sha256": "9febd53cb6501e9bcda3f0c607a1384a0ce164c890676f9d5051bc3424e22c53",
   "external_calls": 0
  },
  "operation": "web_reliability:dns_soa_serial_compare"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/dns-soa-serial-compare-0e470b77/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)