IP-to-ASN-and-Whois-API/README.md

IP-to-ASN Lookup API (fast hehe)

This API allows you to lookup the ASN, country, country name, and provider name for a given IPv4 or IPv6 address.

Base URL

https://cdn.t-w.dev/whois?ip={IP}&locale={locale}

• locale (optional) – de, en, or both (default: both)

---

Request

Method

• GET or POST

Parameters

Name	Type	Required	Description
ip	string	Yes	IPv4 or IPv6 address to query
locale	string	No	Language for country_name: de, en, both

---

Response

Success (200)

Field	Type	Description
ip	string	The queried IP address
asn	string	Autonomous System Number
country	string	2-letter country code of the ASN
country_name	string	Localized country name (locale applied)
description	string	Cleaned provider name (normalized)
logo	string	Provider logo (not all)

Example:

{
  "ip": "8.8.8.8",
  "asn": "15169",
  "country": "US",
  "country_name": "United States / Vereinigte Staaten",
  "description": "Google",
  "logo": "https://cdn.t-w.dev/img/Google.webp"
}

Error (400+)

Field	Type	Description
error	string	Description of the problem

Possible errors:

{ "error": "Missing 'ip' parameter" }

{ "error": "Invalid IP address" }

{ "error": "ASN not found for given IP" }

---

API Flow

flowchart TD
    A[Client Request] --> B{IP parameter provided?}
    B -- No --> C[Return Error: Missing 'ip' parameter]
    B -- Yes --> D{IP valid?}
    D -- No --> E[Return Error: Invalid IP address]
    D -- Yes --> F[Lookup IP in ASN database]
    F --> G{ASN found?}
    G -- Yes --> H[Return JSON with ip, asn, country, country_name, description, logo]
    G -- No --> I[Return Error: ASN not found]