# IPv4 CIDR Prefix Validator

> IPv4 CIDR Prefix Validator is a paid API for AI agents from agentshelf.syntexa.ch, paid per call via x402, $0.009/call, status unknown (last checked 2026-09-29).

Validates whether a given string is a valid IPv4 CIDR prefix notation (e.g. 192.168.1.0/24)

## Facts

- Endpoint: POST https://agentshelf.syntexa.ch/v1/check-ip-cidr4?utm_source=zero.xyz
- Price: $0.009/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-29
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/ipv4-cidr-prefix-validator-5901c5d5
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_e6U0PWBqzKH4fH8MjkVCg

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 ipv4-cidr-prefix-validator-5901c5d5 -d '<json body>'
```

Example prompt: Is '10.0.0.0/8' a valid IPv4 CIDR prefix? Just check the string format and tell me yes or no.

## When to prefer this

Use this endpoint when you need a quick, cheap, deterministic check that a string is a properly formatted IPv4 CIDR prefix — no LLM, no network lookups, pure format validation. Prefer the free sandbox endpoint POST /v1/sandbox/check-ip-cidr4 for testing or when cost matters. Choose this over regex-based agent-side validation when you want a reliable, maintained implementation without writing your own parsing logic.

## Known failure modes

- Empty or missing value field returns validation error
- String exceeding 20000 characters rejected
- Malformed request body returns 400-level error
- Payment of $0.009 USDC required; missing payment returns 402 Payment Required
- Non-string input types may be rejected or coerced

## How this service works

Call when an agent needs whether a string is an IPv4 CIDR prefix. Exact $0.009 USDC. Prefer unpaid POST /v1/sandbox/check-ip-cidr4 first.

## Output

Returns a boolean or structured indication of whether the input string is a valid IPv4 CIDR prefix (e.g. whether it matches correct format such as a valid IPv4 address followed by a valid prefix length /0-/32)

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "data": {
   "description": "JSON value for schema-check SKUs. Omit it on string checks such as email or IBAN."
  },
  "value": {
   "type": "string",
   "examples": [
    "8.8.8.0/24"
   ],
   "maxLength": 20000,
   "minLength": 1,
   "description": "Value to check. The route description names the format: email, phone, IBAN, postal code, VAT, national id, or similar."
  },
  "schema": {
   "description": "JSON Schema document for schema-check SKUs. Omit it on string checks."
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/ipv4-cidr-prefix-validator-5901c5d5/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from agentshelf.syntexa.ch](https://www.zero.xyz/host/agentshelf.syntexa.ch/llms.txt)