API Credit Usage

You need to login or signup to use the BuiltWith API. After logging in your actual API key will be shown here.

Introduction

Get XML and JSON results of websites that are using specific IP addresses, Google Analytics Tags and more.

The general access method is as follows -
https://api.builtwith.com/tag1/api.[xml|json]?KEY=00000000-0000-0000-0000-000000000000&LOOKUP=[ATTRIBUTE-TYPE]-[CODE]

Authentication

You must provide your API key in each lookup. Our endpoints are HTTPS only, providing key encryption. Never expose your API key.

Your API Key is
00000000-0000-0000-0000-000000000000

Get Tag Example

XML Get Single Attribute
https://api.builtwith.com/tag1/api.xml?KEY=00000000-0000-0000-0000-000000000000&LOOKUP=IP-98.158.194.127

JSON Get Single Attribute
https://api.builtwith.com/tag1/api.json?KEY=00000000-0000-0000-0000-000000000000&LOOKUP=CA-PUB-1894893914772263

Reference
Parameters
The following GET parameters can be supplied for lookups
NameExamplesRequired
KEY00000000-0000-0000-0000-000000000000
This is your key, use this for lookups.
Yes
LOOKUPIP-98.158.194.127
CA-PUB-1894893914772263
Attributes that you'd like to lookup - the list of attribute types is available at https://api.builtwith.com/tag1/api.xml?TYPES=true (json)

Multi-Lookup Option
You can lookup 16 attributes at a time - seperate them with a comma. For example IP-98.158.194.127,CA-PUB-1894893914772263 - this dramatically improves throughput.
Yes
Responses
Format: Tag1[Identifiers->Identifier[Match]]
Identifier
Identifier is the sub-option in the identifers array.
NameExampleDescription
ValueIP-98.158.194.127The tag that was looked up.
IdentifersIdentifier explained below.Explained below.
Match
Matches are other domains that have this identifier.
NameExampleDescription
Domaintjoos.comThe domain name of the match.
First2013-03-26T13:00:00ZThe date we first detected this tag.
Last2025-01-13T14:00:00ZThe date we last detected this tag.
Code Examples

Here are implementation examples in different programming languages for making API requests:

var client = new HttpClient();
var request = new HttpRequestMessage
{
    Method = HttpMethod.Get,
    RequestUri = new Uri("https://api.builtwith.com/tag1/api.json" +
                        "?KEY=00000000-0000-0000-0000-000000000000&LOOKUP=CA-PUB-1894893914772263"),
};
using (var response = await client.SendAsync(request))
{
    response.EnsureSuccessStatusCode();
    var body = await response.Content.ReadAsStringAsync();
    Console.WriteLine(body);
}
import requests
url = "https://api.builtwith.com/tag1/api.json"
params = {
    'KEY': '00000000-0000-0000-0000-000000000000',
    'LOOKUP': 'CA-PUB-1894893914772263'
}
response = requests.get(url, params=params)
print(response.json())
<?php
$url = "https://api.builtwith.com/tag1/api.json";
$params = array(
    'KEY' => '00000000-0000-0000-0000-000000000000',
    'LOOKUP' => 'CA-PUB-1894893914772263'
);
$url_with_params = $url . '?' . http_build_query($params);
$response = file_get_contents($url_with_params);
$data = json_decode($response, true);
print_r($data);
?>
const https = require('https');
const url = 'https://api.builtwith.com/tag1/api.json?KEY=00000000-0000-0000-0000-000000000000&LOOKUP=CA-PUB-1894893914772263';
https.get(url, (res) => {
    let data = '';
    res.on('data', (chunk) => {
        data += chunk;
    });
    res.on('end', () => {
        console.log(JSON.parse(data));
    });
}).on('error', (err) => {
    console.log('Error: ' + err.message);
});
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
public class BuiltWithAPI {
    public static void main(String[] args) throws Exception {
        String url = "https://api.builtwith.com/tag1/api.json" +
                    "?KEY=00000000-0000-0000-0000-000000000000&LOOKUP=CA-PUB-1894893914772263";
        URL obj = new URL(url);
        HttpURLConnection con = (HttpURLConnection) obj.openConnection();
        con.setRequestMethod("GET");
        BufferedReader in = new BufferedReader(
            new InputStreamReader(con.getInputStream()));
        String inputLine;
        StringBuffer response = new StringBuffer();
        while ((inputLine = in.readLine()) != null) {
            response.append(inputLine);
        }
        in.close();
        System.out.println(response.toString());
    }
}
require 'net/http'
require 'uri'
require 'json'
uri = URI('https://api.builtwith.com/tag1/api.json')
uri.query = URI.encode_www_form({
    'KEY' => '00000000-0000-0000-0000-000000000000',
    'LOOKUP' => 'CA-PUB-1894893914772263'
})
response = Net::HTTP.get_response(uri)
data = JSON.parse(response.body)
puts data
package main
import (
    "fmt"
    "io/ioutil"
    "net/http"
)
func main() {
    url := "https://api.builtwith.com/tag1/api.json?KEY=00000000-0000-0000-0000-000000000000&LOOKUP=CA-PUB-1894893914772263"
    resp, err := http.Get(url)
    if err != nil {
        panic(err)
    }
    defer resp.Body.Close()
    body, err := ioutil.ReadAll(resp.Body)
    if err != nil {
        panic(err)
    }
    fmt.Println(string(body))
}
curl -X GET "https://api.builtwith.com/tag1/api.json?KEY=00000000-0000-0000-0000-000000000000&LOOKUP=CA-PUB-1894893914772263"
Special Domains

We maintain two lists of use for you when looking up domains. Ignore lists and BuiltWith Suffix lists.

Ignore List
This is our own internal list of domains we do not index. They are either blocked, contains too many misleading technologies or too many subdomains with user generated content.

BuiltWith Suffix List
This is based on the Public Suffix List but includes many additional entries for companies with subdomains that should be considered top level domains. This list provides us with better visibility for internal websites for example it brings northernbeaches.nsw.gov.au to the top level over nsw.gov.au.

Ignore Domains (XML, JSON or TXT)
https://api.builtwith.com/ignoresv1/api.json
Suffix Domains (XML, JSON or TXT)
https://api.builtwith.com/suffixv1/api.json
Error Codes

Note error messages in this format cannot be guaranteed, your implementation should also consider non-200 response codes as errors. The Lookup property will be null (json) or not provided (xml) if the error is server related. View all potential well-formed error codes.

Terms of Use

Our standard terms cover the use all of our APIs.

In general, you can use the API to enhance your product in many ways. The only limitation is you cannot resell the data as-is or provide duplicate functionality to builtwith.com and its associated services.