Punycode Converter API

GET

Docs Get a free API key →

Convert international domain names and detect writing systems.

Convert between Unicode and Punycode for internationalized domain names (IDN).

Try it — live request, no key required

Request

GETapi.apiverve.com/v1/punycode?text=m%C3%BCnchen.de

Query parameters

textstring

Verification

Format

No key required to try it. Get a key to use it in your app.

Example

{
  "status": "ok",
  "error": null,
  "data": {
    "input": "münchen.de",
    "output": "xn--mnchen-3ya.de",
    "mode": "encode",
    "isIDN": true,
    "isDomain": true,
    "scripts": [
      "Latin"
    ],
    "mixedScript": false
  }
}

About the Punycode Converter API

Essential for working with international domain names containing non-ASCII characters like accents, Chinese, Arabic, or Cyrillic. It also detects homograph spoofing — flagging domain labels that mix writing systems (for example a Latin 'a' swapped for a visually identical Cyrillic one), the technique behind look-alike phishing domains.

What people use it for

Domain Registration: Verify and convert international domain names
Web Development: Handle IDN domains in applications
Email Systems: Process internationalized email addresses
Security: Detect homograph attacks using similar-looking Unicode characters

Ways to call it

One endpoint, many ways in — REST with JSON, XML, YAML and CSV, plus GraphQL and an MCP interface for AI agents.

JSON: Default REST response
XML: Markup format
YAML: Human-readable
CSV: Tabular export
GraphQL: Query language
MCP: For AI agents

View all integrations →

How it compares

Side by side with the tools people weigh Punycode Converter against — what each one is better at, in plain terms.

APIVerve vs MXToolbox →

Other ways to use Punycode Converter

Same data, same APIVerve account, same credit balance — one key works on all of them.

Give it to an AI agentConnect over MCP and your agent calls it as a native tool — Claude, Cursor, ChatGPT.on VerveKit

Questions.

Common questions about the Punycode Converter API.

Read the docs →

Which writing systems and languages can this convert?

It handles international domain names across major writing systems, including Cyrillic, Greek, Han, Arabic, and Latin with accents. Both encoding Unicode text to xn-- Punycode and decoding Punycode back to readable Unicode are supported for text inputs up to 1,000 characters.

How many domain conversions does the Free plan cover?

The Free plan covers 100 domain conversions each month at 2 credits per call. If you need higher volume, the Starter plan covers 100,000 conversions monthly, which works out to about $0.30 per 1,000 calls or $0.0003 per call.

Do I get mixed-script spoof detection on the Free plan?

No, the mixed-script flag and the internationalized domain validation flag are premium fields reserved for paid plans. Upgrading to Starter or above unlocks both fields so you can verify valid IDNs and detect when a domain mixes conflicting alphabets to mimic another site.

What happens if I pass a standard ASCII domain?

Standard ASCII domains pass through without errors. Because there are no internationalized characters, the scripts list returns empty and, on paid plans, the mixed-script indicator returns false.

How does the converter identify look-alike phishing domains?

Punycode Converter analyzes each label in a domain to see if it mixes distinct alphabets that no natural language combines, such as swapping a Latin letter for a visually identical Cyrillic character. On paid plans, when this pattern occurs, the mixedScript field flags the domain as a potential spoof.

Request parameters — GET /v1/punycode

Sent in the query string. Premium parameters are accepted on every plan but only take effect on plans that include them. Anything not listed here is dropped rather than passed through.

Required

Parameter	Type	Example	Description
`text`Required	string	`münchen.de`	Unicode text or domain to encode (max 1000 characters) length 0-1000

Optional

Parameter	Type	Example	Description
`mode`Optional	string	`encode`	Conversion mode `encodedecode` default encode

Example request

1
2

curl "https://api.apiverve.com/v1/punycode?text=m%C3%BCnchen.de&mode=encode" \
  -H "x-api-key: YOUR_API_KEY"

Authentication

Send your key in the x-api-key header. That is the only auth step — no token exchange, and no per-endpoint scope to configure.

Header	When	Value
`x-api-key`Required	Every request	Your API key. Header names are case-insensitive, so `X-API-Key` is the same header.
`Authorization`Alternate	Instead of the above	`Bearer <key>` — for clients that only expose bearer auth. Resolves to the same account and the same billing.

401 is the only auth verdict

A 401 means the key is missing, invalid or expired. A 403 means the key is valid but not permitted here — blocked by a key restriction or an IP allow-list. Running out of credits is a 429.

Response — GET /v1/punycode

Every APIVerve endpoint returns the same three top-level keys, so one response handler covers your whole integration: status, error and data. Only data changes shape.

Sample response

{
  "status": "ok",
  "error": null,
  "data": {
    "input": "münchen.de",
    "output": "xn--mnchen-3ya.de",
    "mode": "encode",
    "isIDN": true,
    "isDomain": true,
    "scripts": [
      "Latin"
    ],
    "mixedScript": false
  }
}

Response fields

Paths are relative to data. Premium fields are absent rather than zeroed on plans that do not include them, so check for presence instead of comparing to 0.

Field	Type	Example	Description
`input`	string	`"münchen.de"`	Original Unicode text provided for encoding conversion
`output`	string	`"xn--mnchen-3ya.de"`	Converted Punycode text with xn-- prefix format
`mode`	string	`"encode"`	Conversion mode used for the transformation operation
`isIDN`Premium	boolean	`true`	Indicates if result is valid internationalized domain name
`isDomain`	boolean	`true`	Whether the input was treated as a domain name (that is, it contained a dot) rather than a single label.
`scripts`	array	`[Latin]`	Writing systems (Latin, Cyrillic, Greek, Han, etc.) detected in the domain's non-ASCII labels. Empty for a plain ASCII domain; a single entry for a legitimate international domain
`mixedScript`Premium	boolean	`false`	True when a single domain label mixes writing systems in a way no real language does (e.g. Latin combined with Cyrillic) — the signature of a homograph / look-alike phishing domain. Legitimate combinations such as Japanese (Han + Hiragana/Katakana) are not flagged. Detects cross-script spoofs, not same-script look-alikes

Response headers

Every response carries your balance, so your own code always knows where it stands without polling anything. All four are exposed to browsers through CORS.

Header	What it carries
`x-api-remaining-credits`	Credits left in the current cycle
`x-api-credits-used`	Credits spent in the current cycle
`x-api-max-credits`	The allowance for the cycle
`x-api-version`	Version of the endpoint that answered

Errors

Read the HTTP status first, then error for the specific reason. The body names the parameter that has to change.

Status	Meaning	What to do
`400`	Input was rejected	Read `error`; it names the parameter that has to change.
`401`	Key missing or invalid	Check the header name and the key value.
`403`	Key valid, but not permitted here	A key restriction or an IP allow-list — never a bad key.
`429`	Rate limited, or out of credits	Read `error` to tell them apart, then back off or top up.

What a call costs — 2 credits per call

Credits are shared across every APIVerve API — one balance, one key, one bill. Failed requests never count against it, so a rejected input costs nothing.

Plan	Per month	Credits	Punycode Converter calls	Per 1,000 calls
Free	Free	200	100	Free
Starter	$29.99	200,000	100,000	$0.30
Pro	$99.99	1,000,000	500,000	$0.20
Mega	$299.99	4,000,000	2,000,000	$0.15

Calls are what the credits buy at this API's rate — spend them here, on any of the other APIs, or across both. Nothing is reserved per endpoint.

Compare all pricing tiers →

Call it from cURL — GET /v1/punycode

No SDK to install — this is a plain HTTPS call to /v1/punycode with your key in the x-api-key header. Swap in a real key and it runs as-is.

cURL

1
2

curl "https://api.apiverve.com/v1/punycode" \
  -H "x-api-key: YOUR_API_KEY"

Resources

GitHubapiverve/punycode-apiSource, issues and the examples this page is built from.ReferencePunycode Converter API docsEvery parameter, every response field, and the errors.ParametersWhat this call acceptsRequired and optional inputs, with example values.

Also published for

@apiverve/punycodenpm APIVerve.API.PunycodeConverterNuGet

Only the languages APIVerve ships a client for are listed — the rest call the endpoint directly over HTTPS.

Call it from Node.js — GET /v1/punycode

Install the Node.js SDK, then call the Punycode Converter API with your key. The client wraps the same HTTPS request, so anything it returns is what the endpoint returns.

Install — npm

npm install @apiverve/punycode

Node.js

const res = await fetch("https://api.apiverve.com/v1/punycode", {
  headers: { "x-api-key": "YOUR_API_KEY" },
});
const { data } = await res.json();
console.log(data);

Resources

npm@apiverve/punycodeThe published Node.js client, versioned and signed.GitHubapiverve/punycode-apiSource, issues and the examples this page is built from.ReferencePunycode Converter API docsEvery parameter, every response field, and the errors.ParametersWhat this call acceptsRequired and optional inputs, with example values.

Also published for

APIVerve.API.PunycodeConverterNuGet

Only the languages APIVerve ships a client for are listed — the rest call the endpoint directly over HTTPS.

Call it from Python — GET /v1/punycode

No SDK to install — this is a plain HTTPS call to /v1/punycode with your key in the x-api-key header. Swap in a real key and it runs as-is.

Python

import requests

res = requests.get(
    "https://api.apiverve.com/v1/punycode",
    headers={"x-api-key": "YOUR_API_KEY"},
)
print(res.json()["data"])

Resources

Also published for

@apiverve/punycodenpm APIVerve.API.PunycodeConverterNuGet

Only the languages APIVerve ships a client for are listed — the rest call the endpoint directly over HTTPS.

Call it from C# / .NET — GET /v1/punycode

Install the C# / .NET SDK, then call the Punycode Converter API with your key. The client wraps the same HTTPS request, so anything it returns is what the endpoint returns.

Install — NuGet

dotnet add package APIVerve.API.PunycodeConverter

C# / .NET

using var client = new HttpClient();
client.DefaultRequestHeaders.Add("x-api-key", "YOUR_API_KEY");

var json = await client.GetStringAsync("https://api.apiverve.com/v1/punycode");
Console.WriteLine(json);

Resources

NuGetAPIVerve.API.PunycodeConverterThe published C# / .NET client, versioned and signed.GitHubapiverve/punycode-apiSource, issues and the examples this page is built from.ReferencePunycode Converter API docsEvery parameter, every response field, and the errors.ParametersWhat this call acceptsRequired and optional inputs, with example values.

Also published for

@apiverve/punycodenpm

Only the languages APIVerve ships a client for are listed — the rest call the endpoint directly over HTTPS.

Call it from Go — GET /v1/punycode

No SDK to install — this is a plain HTTPS call to /v1/punycode with your key in the x-api-key header. Swap in a real key and it runs as-is.

req, _ := http.NewRequest("GET", "https://api.apiverve.com/v1/punycode", nil)
req.Header.Set("x-api-key", "YOUR_API_KEY")

res, _ := http.DefaultClient.Do(req)
defer res.Body.Close()
body, _ := io.ReadAll(res.Body)
fmt.Println(string(body))

Resources

Also published for

@apiverve/punycodenpm APIVerve.API.PunycodeConverterNuGet

Only the languages APIVerve ships a client for are listed — the rest call the endpoint directly over HTTPS.

Call it from PHP — GET /v1/punycode

No SDK to install — this is a plain HTTPS call to /v1/punycode with your key in the x-api-key header. Swap in a real key and it runs as-is.

PHP

$ch = curl_init("https://api.apiverve.com/v1/punycode");
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_HTTPHEADER, ["x-api-key: YOUR_API_KEY"]);

$response = curl_exec($ch);
echo $response;

Resources

Also published for

@apiverve/punycodenpm APIVerve.API.PunycodeConverterNuGet

Only the languages APIVerve ships a client for are listed — the rest call the endpoint directly over HTTPS.

Call it from Ruby — GET /v1/punycode

No SDK to install — this is a plain HTTPS call to /v1/punycode with your key in the x-api-key header. Swap in a real key and it runs as-is.

Ruby

require "net/http"

uri = URI("https://api.apiverve.com/v1/punycode")
req = Net::HTTP::Get.new(uri)
req["x-api-key"] = "YOUR_API_KEY"

res = Net::HTTP.start(uri.hostname, uri.port, use_ssl: true) { |h| h.request(req) }
puts res.body

Resources

Also published for

@apiverve/punycodenpm APIVerve.API.PunycodeConverterNuGet

Only the languages APIVerve ships a client for are listed — the rest call the endpoint directly over HTTPS.

Data Conversion

View all 33 →

All articles →

Extract Clean Content from Any WebpageTurn messy web pages into clean Markdown. Perfect for content migration, archiving, AI training data, and building read-later tools.Read

Generate PDFs from HTML with an APIConvert HTML to PDF programmatically. Tutorial covering invoices, reports, receipts, and certificates with code examples.Read

Automating Visual Testing With ScreenshotsCatch visual bugs before users do. Here's how to add screenshot-based testing to your workflow.Read

Punycode Converter API

Try it — live request, no key required

About the Punycode Converter API

What people use it for

Ways to call it

How it compares

Other ways to use Punycode Converter

Questions.

Request parameters — GET /v1/punycode

Required

Optional

Authentication

Response — GET /v1/punycode

Response fields

Response headers

Errors

What a call costs — 2 credits per call

Call it from cURL — GET /v1/punycode

Resources

Also published for

Call it from Node.js — GET /v1/punycode

Resources

Also published for

Call it from Python — GET /v1/punycode

Resources

Also published for

Call it from C# / .NET — GET /v1/punycode

Resources

Also published for

Call it from Go — GET /v1/punycode

Resources

Also published for

Call it from PHP — GET /v1/punycode

Resources

Also published for

Call it from Ruby — GET /v1/punycode

Resources

Also published for

Zero-code embed — one snippet, no backend

Changelog — Punycode Converter API

Data Conversion

Related articles

Ready to build with Punycode Converter? Start with 200 free credits — one key unlocks all 300+ APIs.

Explore the catalog