IP range to CIDR API
Summarises an IPv4 or IPv6 range into the fewest CIDR blocks that cover exactly the addresses from start to end; that is at most 62 blocks for IPv4 and 254 for IPv6. Both ends must have the same version and start must not be after end.
GET https://api.lookproof.dev/v1/ip/range-to-cidr
Updated 2026-10-09
Examples use the Base (eip155:8453) network.
Input
Query parameters.
| Name | Type | Required | Limits | Description |
|---|---|---|---|---|
start | string | Yes | 2–64 characters | The first address of the range. |
end | string | Yes | 2–64 characters | The last address of the range: same IP version as start and not before it. |
Example request
curl -i 'https://api.lookproof.dev/v1/ip/range-to-cidr?end=192.0.2.20&start=192.0.2.10'import asyncio
import os
from eth_account import Account
from x402 import x402Client
from x402.http.clients import x402HttpxClient
from x402.mechanisms.evm import EthAccountSigner
from x402.mechanisms.evm.exact import register_exact_evm_client
async def main() -> None:
signer = EthAccountSigner(Account.from_key(os.environ["EVM_PRIVATE_KEY"]))
client = register_exact_evm_client(x402Client(), signer, networks="eip155:8453")
async with x402HttpxClient(client) as http:
response = await http.get('https://api.lookproof.dev/v1/ip/range-to-cidr', params={'end': '192.0.2.20', 'start': '192.0.2.10'})
response.raise_for_status()
print(response.json())
asyncio.run(main())
import { wrapFetchWithPaymentFromConfig } from "@x402/fetch";
import { ExactEvmScheme } from "@x402/evm";
import { privateKeyToAccount } from "viem/accounts";
const account = privateKeyToAccount(process.env.EVM_PRIVATE_KEY);
const fetchWithPayment = wrapFetchWithPaymentFromConfig(fetch, {
schemes: [{ network: "eip155:8453", client: new ExactEvmScheme(account) }],
});
const response = await fetchWithPayment("https://api.lookproof.dev/v1/ip/range-to-cidr?end=192.0.2.20&start=192.0.2.10");
console.log(await response.json());
curl: unpaid request — returns 402 with the price (PAYMENT-REQUIRED). The Python and JavaScript clients pay it and send the request again. Only ordinary wallets (EOA) can pay; smart-contract wallets get a 402 without charge. See payments.
Example response
{
"checked_at": "2026-10-24T12:00:00Z",
"data": {
"cidrs": [
"192.0.2.10/31",
"192.0.2.12/30",
"192.0.2.16/30",
"192.0.2.20/32"
],
"end": "192.0.2.20",
"size": "11",
"start": "192.0.2.10",
"version": 4
},
"endpoint": "ip.range_to_cidr",
"findings": [],
"meta": {
"cache_hit": false,
"duration_ms": 42,
"fresh_until": "2026-10-24T12:05:00Z",
"observed_at": "2026-10-24T12:00:00Z",
"resolver": null,
"source": "offline"
},
"request_id": "req_aaaaaaaaaaaaaaaaaaaaaaaaaa",
"schema_version": "1.0",
"status": "ok"
}Response fields
| Field | Meaning |
|---|---|
request_id | Unique id of this request. Quote it when you contact support. |
endpoint | The endpoint id, for example mail.spf. |
schema_version | Version of the response format, currently 1.0. |
checked_at | When the check ran (ISO 8601, UTC). |
status | ok, info, warning or error from the worst finding, or unknown when the check was incomplete. unknown is not an error in the domain. |
data | The check's own data. Its fields are listed below. |
findings | What was found: code, severity, message, explanation and evidence. |
meta | Duration, cache use, resolver and how long the result stays fresh. |
Fields in data
| Field | Type |
|---|---|
start | string |
end | string |
version | one of 4, 6 |
size | string |
cidrs | array of string |
Status codes
| Status | Code | Meaning | Do you pay? |
|---|---|---|---|
| 200 | — | The result is delivered, also when it has negative findings. | Yes: charged once per payment; redelivery of the same payment is free |
| 402 | — | Payment is required, or the attached payment was refused. The body states the price. | No |
| 400 | bad_request | The request is malformed. | No |
| 409 | payment_in_progress, payment_bound_to_other_request | This payment is already being processed, or it is bound to a different request. No new payment is taken. | No |
| 422 | invalid_input | The input failed validation on a request that carries a payment; nothing is charged. Without a payment, invalid input gets a 402 whose error field names the problem. | No |
| 429 | rate_limited | Too many requests from this IP address or payer. | No |
| 502 | check_failed | The check could not be completed. | No |
| 503 | busy, unavailable, payments_unavailable | The service is busy or temporarily unavailable. | No |
| 504 | deadline_exceeded | The check ran out of time. | No |
Errors use the common error body. See errors.