curl --request POST \
  --url https://api.jusfy.dev/calculators/api/calculadoras/inss \
  --header 'Content-Type: application/json' \
  --header 'x-api-key: <api-key>' \
  --data '
{
  "double_refund": false,
  "installments": [
    {
      "id": 1,
      "date": "2021-01-10",
      "amount": 1200
    },
    {
      "id": 2,
      "date": "2021-02-10",
      "amount": 1200
    },
    {
      "id": 3,
      "date": "2021-03-10",
      "amount": 1200
    }
  ],
  "correction_differences_index_id": 6,
  "interest_differences": 1,
  "agreement": true
}
'

import requests

url = "https://api.jusfy.dev/calculators/api/calculadoras/inss"

payload = {
    "double_refund": False,
    "installments": [
        {
            "id": 1,
            "date": "2021-01-10",
            "amount": 1200
        },
        {
            "id": 2,
            "date": "2021-02-10",
            "amount": 1200
        },
        {
            "id": 3,
            "date": "2021-03-10",
            "amount": 1200
        }
    ],
    "correction_differences_index_id": 6,
    "interest_differences": 1,
    "agreement": True
}
headers = {
    "x-api-key": "<api-key>",
    "Content-Type": "application/json"
}

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

print(response.text)

const options = {
  method: 'POST',
  headers: {'x-api-key': '<api-key>', 'Content-Type': 'application/json'},
  body: JSON.stringify({
    double_refund: false,
    installments: [
      {id: 1, date: '2021-01-10', amount: 1200},
      {id: 2, date: '2021-02-10', amount: 1200},
      {id: 3, date: '2021-03-10', amount: 1200}
    ],
    correction_differences_index_id: 6,
    interest_differences: 1,
    agreement: true
  })
};

fetch('https://api.jusfy.dev/calculators/api/calculadoras/inss', 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.jusfy.dev/calculators/api/calculadoras/inss",
  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([
    'double_refund' => false,
    'installments' => [
        [
                'id' => 1,
                'date' => '2021-01-10',
                'amount' => 1200
        ],
        [
                'id' => 2,
                'date' => '2021-02-10',
                'amount' => 1200
        ],
        [
                'id' => 3,
                'date' => '2021-03-10',
                'amount' => 1200
        ]
    ],
    'correction_differences_index_id' => 6,
    'interest_differences' => 1,
    'agreement' => true
  ]),
  CURLOPT_HTTPHEADER => [
    "Content-Type: application/json",
    "x-api-key: <api-key>"
  ],
]);

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

curl_close($curl);

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