curl --request POST \
  --url https://sandbox.api.fin.com/v2/customers/{customer_id}/business/attach \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "formation_documents": [
    {
      "type": "EVIDENCE_OF_DIRECTORS_AND_CONTROLLERS",
      "description": "Certificate of Incorporation",
      "files": [
        {
          "uri": "/AbAcQ4hn_0652746727637.pdf"
        }
      ]
    },
    {
      "type": "REGISTRATION_DOCUMENT",
      "description": "Business registration doc",
      "files": [
        {
          "uri": "/AbAcQ4hn_0652746727638.pdf"
        }
      ]
    }
  ],
  "ownership_documents": [
    {
      "type": "PROOF_OF_SIGNATORY_AUTHORITY",
      "description": "Shareholder Registry",
      "files": [
        {
          "uri": "/XyZ123mn_0652746727639.pdf"
        }
      ]
    }
  ],
  "supporting_documents": [
    {
      "type": "PROOF_OF_SOURCE_OF_FUNDS",
      "files": [
        {
          "uri": "/PoAdef45_0652746727640.pdf"
        }
      ]
    },
    {
      "type": "PROOF_OF_ADDRESS",
      "files": [
        {
          "uri": "/PoAdef45_0652746727641.pdf"
        }
      ]
    }
  ],
  "tos_policies_value": "6955e70b-f9f3-4076-b1ce-5c897085dd24"
}
'

const url = 'https://sandbox.api.fin.com/v2/customers/{customer_id}/business/attach';
const options = {
  method: 'POST',
  headers: {Authorization: 'Bearer <token>', 'Content-Type': 'application/json'},
  body: JSON.stringify({
    formation_documents: [
      {
        type: 'EVIDENCE_OF_DIRECTORS_AND_CONTROLLERS',
        description: 'Certificate of Incorporation',
        files: [{uri: '/AbAcQ4hn_0652746727637.pdf'}]
      },
      {
        type: 'REGISTRATION_DOCUMENT',
        description: 'Business registration doc',
        files: [{uri: '/AbAcQ4hn_0652746727638.pdf'}]
      }
    ],
    ownership_documents: [
      {
        type: 'PROOF_OF_SIGNATORY_AUTHORITY',
        description: 'Shareholder Registry',
        files: [{uri: '/XyZ123mn_0652746727639.pdf'}]
      }
    ],
    supporting_documents: [
      {
        type: 'PROOF_OF_SOURCE_OF_FUNDS',
        files: [{uri: '/PoAdef45_0652746727640.pdf'}]
      },
      {type: 'PROOF_OF_ADDRESS', files: [{uri: '/PoAdef45_0652746727641.pdf'}]}
    ],
    tos_policies_value: '6955e70b-f9f3-4076-b1ce-5c897085dd24'
  })
};

fetch(url, options)
  .then(res => res.json())
  .then(json => console.log(json))
  .catch(err => console.error(err));

HttpResponse<String> response = Unirest.post("https://sandbox.api.fin.com/v2/customers/{customer_id}/business/attach")
  .header("Authorization", "Bearer <token>")
  .header("Content-Type", "application/json")
  .body("{\n  \"formation_documents\": [\n    {\n      \"type\": \"EVIDENCE_OF_DIRECTORS_AND_CONTROLLERS\",\n      \"description\": \"Certificate of Incorporation\",\n      \"files\": [\n        {\n          \"uri\": \"/AbAcQ4hn_0652746727637.pdf\"\n        }\n      ]\n    },\n    {\n      \"type\": \"REGISTRATION_DOCUMENT\",\n      \"description\": \"Business registration doc\",\n      \"files\": [\n        {\n          \"uri\": \"/AbAcQ4hn_0652746727638.pdf\"\n        }\n      ]\n    }\n  ],\n  \"ownership_documents\": [\n    {\n      \"type\": \"PROOF_OF_SIGNATORY_AUTHORITY\",\n      \"description\": \"Shareholder Registry\",\n      \"files\": [\n        {\n          \"uri\": \"/XyZ123mn_0652746727639.pdf\"\n        }\n      ]\n    }\n  ],\n  \"supporting_documents\": [\n    {\n      \"type\": \"PROOF_OF_SOURCE_OF_FUNDS\",\n      \"files\": [\n        {\n          \"uri\": \"/PoAdef45_0652746727640.pdf\"\n        }\n      ]\n    },\n    {\n      \"type\": \"PROOF_OF_ADDRESS\",\n      \"files\": [\n        {\n          \"uri\": \"/PoAdef45_0652746727641.pdf\"\n        }\n      ]\n    }\n  ],\n  \"tos_policies_value\": \"6955e70b-f9f3-4076-b1ce-5c897085dd24\"\n}")
  .asString();

import requests

url = "https://sandbox.api.fin.com/v2/customers/{customer_id}/business/attach"

payload = {
    "formation_documents": [
        {
            "type": "EVIDENCE_OF_DIRECTORS_AND_CONTROLLERS",
            "description": "Certificate of Incorporation",
            "files": [{ "uri": "/AbAcQ4hn_0652746727637.pdf" }]
        },
        {
            "type": "REGISTRATION_DOCUMENT",
            "description": "Business registration doc",
            "files": [{ "uri": "/AbAcQ4hn_0652746727638.pdf" }]
        }
    ],
    "ownership_documents": [
        {
            "type": "PROOF_OF_SIGNATORY_AUTHORITY",
            "description": "Shareholder Registry",
            "files": [{ "uri": "/XyZ123mn_0652746727639.pdf" }]
        }
    ],
    "supporting_documents": [
        {
            "type": "PROOF_OF_SOURCE_OF_FUNDS",
            "files": [{ "uri": "/PoAdef45_0652746727640.pdf" }]
        },
        {
            "type": "PROOF_OF_ADDRESS",
            "files": [{ "uri": "/PoAdef45_0652746727641.pdf" }]
        }
    ],
    "tos_policies_value": "6955e70b-f9f3-4076-b1ce-5c897085dd24"
}
headers = {
    "Authorization": "Bearer <token>",
    "Content-Type": "application/json"
}

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

print(response.text)

package main

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

func main() {

	url := "https://sandbox.api.fin.com/v2/customers/{customer_id}/business/attach"

	payload := strings.NewReader("{\n  \"formation_documents\": [\n    {\n      \"type\": \"EVIDENCE_OF_DIRECTORS_AND_CONTROLLERS\",\n      \"description\": \"Certificate of Incorporation\",\n      \"files\": [\n        {\n          \"uri\": \"/AbAcQ4hn_0652746727637.pdf\"\n        }\n      ]\n    },\n    {\n      \"type\": \"REGISTRATION_DOCUMENT\",\n      \"description\": \"Business registration doc\",\n      \"files\": [\n        {\n          \"uri\": \"/AbAcQ4hn_0652746727638.pdf\"\n        }\n      ]\n    }\n  ],\n  \"ownership_documents\": [\n    {\n      \"type\": \"PROOF_OF_SIGNATORY_AUTHORITY\",\n      \"description\": \"Shareholder Registry\",\n      \"files\": [\n        {\n          \"uri\": \"/XyZ123mn_0652746727639.pdf\"\n        }\n      ]\n    }\n  ],\n  \"supporting_documents\": [\n    {\n      \"type\": \"PROOF_OF_SOURCE_OF_FUNDS\",\n      \"files\": [\n        {\n          \"uri\": \"/PoAdef45_0652746727640.pdf\"\n        }\n      ]\n    },\n    {\n      \"type\": \"PROOF_OF_ADDRESS\",\n      \"files\": [\n        {\n          \"uri\": \"/PoAdef45_0652746727641.pdf\"\n        }\n      ]\n    }\n  ],\n  \"tos_policies_value\": \"6955e70b-f9f3-4076-b1ce-5c897085dd24\"\n}")

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

	req.Header.Add("Authorization", "Bearer <token>")
	req.Header.Add("Content-Type", "application/json")

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

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

	fmt.Println(string(body))

}

{
  "data": {}
}

{
  "status": 400,
  "message": "Validation failed",
  "data": {}
}

{
  "message": "Authentication failed"
}

{
  "message": "Resource not found"
}

{
  "message": "<string>",
  "errors": [
    {}
  ]
}