curl --request POST \
  --url https://api.tahsil.dev/banks/transactions/{id}/assignments \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --header 'x-company-id: <x-company-id>' \
  --data '
{
  "reference": {
    "source": "<string>",
    "entityType": "<string>",
    "externalId": "<string>",
    "label": "<string>"
  }
}
'

const options = {
  method: 'POST',
  headers: {
    'x-company-id': '<x-company-id>',
    Authorization: 'Bearer <token>',
    'Content-Type': 'application/json'
  },
  body: JSON.stringify({
    reference: {
      source: '<string>',
      entityType: '<string>',
      externalId: '<string>',
      label: '<string>'
    }
  })
};

fetch('https://api.tahsil.dev/banks/transactions/{id}/assignments', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://api.tahsil.dev/banks/transactions/{id}/assignments",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "POST",
  CURLOPT_POSTFIELDS => json_encode([
    'reference' => [
        'source' => '<string>',
        'entityType' => '<string>',
        'externalId' => '<string>',
        'label' => '<string>'
    ]
  ]),
  CURLOPT_HTTPHEADER => [
    "Authorization: Bearer <token>",
    "Content-Type: application/json",
    "x-company-id: <x-company-id>"
  ],
]);

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  echo $response;
}

{
  "status": true,
  "result": {
    "id": "64f000000000000000000001"
  }
}

{
  "status": false,
  "error": {
    "code": "AUTHENTICATION_REQUIRED",
    "message": "Authentication is required"
  }
}