Relationships API

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 relationships between websites that show what sites are linked together, by what and for how long.

Relationship API uses 1 API credit per 500 relationships.

The general access method is as follows -
https://api.builtwith.com/rv4/api.[xml|json|csv]?KEY=00000000-0000-0000-0000-000000000000&LOOKUP=[DOMAIN]

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 Domain Example

JSON Get Single Domain
https://api.builtwith.com/rv4/api.json?KEY=00000000-0000-0000-0000-000000000000&LOOKUP=builtwith.com

XML Get Single Domain
https://api.builtwith.com/rv4/api.xml?KEY=00000000-0000-0000-0000-000000000000&LOOKUP=hotelscombined.com

CSV Get Single Domain
https://api.builtwith.com/rv4/api.csv?KEY=00000000-0000-0000-0000-000000000000&LOOKUP=builtwith.com

TSV Get Single Domain
https://api.builtwith.com/rv4/api.Tsv?KEY=00000000-0000-0000-0000-000000000000&LOOKUP=builtwith.com

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
LOOKUPcnn.com
news.ycombinator.com
Domains and sub-domains work with the Relationship API (not internal pages)
Multi-Lookup Option
When doing RAW domain lookups, you can parse up to 16 domains at once as a CSV. For example cnn.com,about.com,builtwith.com - this dramatically improves throughput.
Yes
OFFSET500
The offset of pages for relationship results. next_offset in the response has the offset and more_results will be true.
No
IPyes
Load website IP data, this increases the amount of results considerably.
No
API Meta
NameExampleDescription
results24The total amount of relationship results for this lookup
max_per_page500The maximum amount of results we will bring back per lookup.
next_skip1500The number to provide as OFFSET parameter for next page of results if more_results is true.
more_resultstrueThis will be true if there's more results.
Responses
Format: Relationships[Relationship->Identifiers[Identifer]]
Relationship
Results is the top level response that identifies the lookup.
NameExampleDescription
Domainhotelscombined.comThe domain that was looked up.
IdentifiersIdentifier explained below.Explained below.
Identifier
Identifiers are the unique codes that are found on the domain and other domains that also have it.
NameExampleDescription
Typegoogle-analyticsThe type of identifier See all Types
Value454517The value of the identifier - typically the code of the identifier like an IP address or an account id.
First1368860400000The date we first detected this identifier in epoch ms.
Last1398860400000The date we last detected this identifier in epoch ms.
MatchesMatch explained below.Explain below.
Match
Matches are other domains that have this identifier.
NameExampleDescription
Domaincom-hotel.comThe domain name of the match.
First1398860400000The date we first detected this on the matched domain in epoch ms.
Last1418860400000The date we last detected this on the matched domain in epoch ms.
OverlaptrueIf this domain used the identifier at the same time as the lookup Domain.
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/rv4/api.json" +
                        "?KEY=00000000-0000-0000-0000-000000000000&LOOKUP=wayfair.com"),
};
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/rv4/api.json"
params = {
    'KEY': '00000000-0000-0000-0000-000000000000',
    'LOOKUP': 'wayfair.com'
}
response = requests.get(url, params=params)
print(response.json())
<?php
$url = "https://api.builtwith.com/rv4/api.json";
$params = array(
    'KEY' => '00000000-0000-0000-0000-000000000000',
    'LOOKUP' => 'wayfair.com'
);
$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/rv4/api.json?KEY=00000000-0000-0000-0000-000000000000&LOOKUP=wayfair.com';
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/rv4/api.json" +
                    "?KEY=00000000-0000-0000-0000-000000000000&LOOKUP=wayfair.com";
        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/rv4/api.json')
uri.query = URI.encode_www_form({
    'KEY' => '00000000-0000-0000-0000-000000000000',
    'LOOKUP' => 'wayfair.com'
})
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/rv4/api.json?KEY=00000000-0000-0000-0000-000000000000&LOOKUP=wayfair.com"
    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/rv4/api.json?KEY=00000000-0000-0000-0000-000000000000&LOOKUP=wayfair.com"
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.