# Lookproof CIDR Subnet Splitter

> Lookproof CIDR Subnet Splitter is a paid API for AI agents from api.lookproof.dev, paid per call via x402, $0.002/call, status unknown (last checked 2026-10-31).

Splits an IPv4 or IPv6 CIDR block into equal subnets of a specified longer prefix, returning up to 256 subnets in order

## Facts

- Endpoint: GET https://api.lookproof.dev/v1/ip/subnets?utm_source=zero.xyz
- Price: $0.002/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-31
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/lookproof-cidr-subnet-splitter-0ac2fe15
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_xWv42b3Jj1AiXGgxKOA33

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 lookproof-cidr-subnet-splitter-0ac2fe15
```

Example prompt: Split 192.0.2.0/24 into /26 subnets and list them all for me so I can plan which blocks to assign to each team.

## When to prefer this

Use this endpoint when an agent needs to enumerate subnets within a CIDR block for IP address planning, infrastructure layout, or subnet assignment tasks. It runs offline and is deterministic, making it ideal for planning workflows. It caps output at 256 subnets, so it is best suited for moderate splits; if a finer split is needed, restructure the request into smaller parent blocks first.

## Known failure modes

- Requested split produces more than 256 subnets — refused with an error before any computation
- Prefix length shorter than or equal to the CIDR prefix (no subdivision possible)
- Prefix length out of range (e.g. >32 for IPv4 or >128 for IPv6)
- Malformed CIDR notation in the cidr parameter
- Mismatched IP version between CIDR and prefix length

## How this service works

Check SPF, DMARC, DKIM, MTA-STS, DNSSEC and more, with results that explain what was found and why. Free browser checks and a pay-per-request API with x402.

## Output

An ordered list of up to 256 subnets derived from the input CIDR block, each expressed at the requested longer prefix length. Requests that would produce more than 256 subnets are rejected before any computation occurs. The response is computed offline without external DNS or routing lookups.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET",
      "HEAD",
      "DELETE"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "title": "SubnetsInput",
     "required": [
      "cidr",
      "prefix"
     ],
     "properties": {
      "cidr": {
       "type": "string",
       "title": "Cidr",
       "maxLength": 64,
       "minLength": 2
      },
      "prefix": {
       "type": "integer",
       "title": "Prefix",
       "maximum": 128,
       "minimum": 0
      }
     },
     "additionalProperties": false
    }
   },
   "additionalProperties": false
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/lookproof-cidr-subnet-splitter-0ac2fe15/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.lookproof.dev](https://www.zero.xyz/host/api.lookproof.dev/llms.txt)