> For clean Markdown of any page, append .md to the page URL.
> For a complete documentation index, see https://docs.coperniq.io/api-reference/vendors/create-vendor-project-link/llms.txt.
> For AI client integration (Claude Code, Cursor, etc.), connect to the MCP server at https://docs.coperniq.io/_mcp/server.

# Create Vendor-Project Link

POST https://api.coperniq.io/v1/projects/{project_id}/vendors/{vendor_id}

Associate a vendor with a project (many-to-many relationship).

A vendor can be linked to multiple projects and a project can have multiple vendors.


Reference: https://docs.coperniq.io/api-reference/vendors/create-vendor-project-link

## Authentication

- `x-api-key` header (required) — API Key authentication via header

## Request

### Path parameters

- `project_id` (string, required)
- `vendor_id` (string, required)

## Response

### 200

Vendor linked successfully to project

- `message` (string, optional)

## Errors

### 401 Unauthorized Error

Authentication failed

- `message` (string, optional)
- `code` (enum, optional)
  - Allowed values: `NOT_FOUND`

### 404 Not Found Error

Resource not found

- `message` (string, optional)
- `code` (enum, optional)
  - Allowed values: `NOT_FOUND`

## Examples

**Response**

```json
{
  "message": "Vendor linked successfully to project"
}
```

**SDK Code**

```python
import requests

url = "https://api.coperniq.io/v1/projects/project_id/vendors/vendor_id"

headers = {"x-api-key": "<apiKey>"}

response = requests.post(url, headers=headers)

print(response.json())
```

```javascript
const url = 'https://api.coperniq.io/v1/projects/project_id/vendors/vendor_id';
const options = {method: 'POST', headers: {'x-api-key': '<apiKey>'}};

try {
  const response = await fetch(url, options);
  const data = await response.json();
  console.log(data);
} catch (error) {
  console.error(error);
}
```

```go
package main

import (
	"fmt"
	"net/http"
	"io"
)

func main() {

	url := "https://api.coperniq.io/v1/projects/project_id/vendors/vendor_id"

	req, _ := http.NewRequest("POST", url, nil)

	req.Header.Add("x-api-key", "<apiKey>")

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := io.ReadAll(res.Body)

	fmt.Println(res)
	fmt.Println(string(body))

}
```

```ruby
require 'uri'
require 'net/http'

url = URI("https://api.coperniq.io/v1/projects/project_id/vendors/vendor_id")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Post.new(url)
request["x-api-key"] = '<apiKey>'

response = http.request(request)
puts response.read_body
```

```java
import com.mashape.unirest.http.HttpResponse;
import com.mashape.unirest.http.Unirest;

HttpResponse<String> response = Unirest.post("https://api.coperniq.io/v1/projects/project_id/vendors/vendor_id")
  .header("x-api-key", "<apiKey>")
  .asString();
```

```php
<?php
require_once('vendor/autoload.php');

$client = new \GuzzleHttp\Client();

$response = $client->request('POST', 'https://api.coperniq.io/v1/projects/project_id/vendors/vendor_id', [
  'headers' => [
    'x-api-key' => '<apiKey>',
  ],
]);

echo $response->getBody();
```

```csharp
using RestSharp;

var client = new RestClient("https://api.coperniq.io/v1/projects/project_id/vendors/vendor_id");
var request = new RestRequest(Method.POST);
request.AddHeader("x-api-key", "<apiKey>");
IRestResponse response = client.Execute(request);
```

```swift
import Foundation

let headers = ["x-api-key": "<apiKey>"]

let request = NSMutableURLRequest(url: NSURL(string: "https://api.coperniq.io/v1/projects/project_id/vendors/vendor_id")! as URL,
                                        cachePolicy: .useProtocolCachePolicy,
                                    timeoutInterval: 10.0)
request.httpMethod = "POST"
request.allHTTPHeaderFields = headers

let session = URLSession.shared
let dataTask = session.dataTask(with: request as URLRequest, completionHandler: { (data, response, error) -> Void in
  if (error != nil) {
    print(error as Any)
  } else {
    let httpResponse = response as? HTTPURLResponse
    print(httpResponse)
  }
})

dataTask.resume()
```

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