IDN converter API

Maps the name with UTS 46 and checks every label with IDNA2008 (RFC 5891-5893): disallowed characters, hyphen, context and bidi rules, lengths, and letters from mixed scripts in one label, a homograph risk. Returns both forms per label. Nothing is looked up.

GET https://api.lookproof.dev/v1/dns/idn

Updated 2026-10-09

Examples use the Base (eip155:8453) network.

Input

Query parameters.

Name	Type	Required	Limits	Description
`name`	string	Yes	1–1024 characters	A domain name in Unicode or ASCII form, e.g. bücher.example.com.

Example request

curl -i 'https://api.lookproof.dev/v1/dns/idn?name=b%C3%BCcher.example.com'

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/dns/idn', params={'name': 'bücher.example.com'})
        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/dns/idn?name=b%C3%BCcher.example.com");
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": {
    "ascii": "xn--bcher-kva.example.com",
    "is_idn": true,
    "labels": [
      {
        "ascii": "xn--bcher-kva",
        "is_idn": true,
        "scripts": [
          "Latin"
        ],
        "unicode": "bücher"
      },
      {
        "ascii": "example",
        "is_idn": false,
        "scripts": [
          "Latin"
        ],
        "unicode": "example"
      },
      {
        "ascii": "com",
        "is_idn": false,
        "scripts": [
          "Latin"
        ],
        "unicode": "com"
      }
    ],
    "name": "bücher.example.com",
    "problems": [],
    "unicode": "bücher.example.com",
    "valid": true
  },
  "endpoint": "dns.idn",
  "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
`name`	string
`ascii`	string or null
`unicode`	string or null
`is_idn`	boolean
`valid`	boolean
`labels`	array of IdnLabel
`problems`	array of IdnProblem

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.

Findings this endpoint can return

Internationalised names (3)

Error IDN_INVALID The name is not a valid internationalised domain name.
Warning IDN_MIXED_SCRIPT A label mixes letters from different scripts, a homograph risk.
Info IDN_NOT_IDN The name is plain ASCII and has no internationalised labels.

IDN converter API

Input

Example request

Example response

Response fields

Fields in data

Status codes

Findings this endpoint can return

Fields in `data`