curl --request POST \
  --url https://kourio.app/v1/templates/preview \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "blocks": [
    {
      "type": "heading",
      "runs": [
        {
          "text": "<string>",
          "bold": true,
          "italic": true,
          "color": "<string>",
          "href": "<string>"
        }
      ]
    }
  ],
  "fromName": "",
  "subject": "",
  "previewText": "",
  "style": {
    "pageBackground": "#F4F4F5",
    "pagePadding": 32,
    "bodyBackground": "#FFFFFF",
    "bodyText": "#18181B",
    "bodyBorderColor": "#E4E4E7",
    "accent": "#2F5CD8",
    "width": 600,
    "padding": 34,
    "radius": 12,
    "border": 1
  },
  "variables": {}
}
'

import requests

url = "https://kourio.app/v1/templates/preview"

payload = {
    "blocks": [
        {
            "type": "heading",
            "runs": [
                {
                    "text": "<string>",
                    "bold": True,
                    "italic": True,
                    "color": "<string>",
                    "href": "<string>"
                }
            ]
        }
    ],
    "fromName": "",
    "subject": "",
    "previewText": "",
    "style": {
        "pageBackground": "#F4F4F5",
        "pagePadding": 32,
        "bodyBackground": "#FFFFFF",
        "bodyText": "#18181B",
        "bodyBorderColor": "#E4E4E7",
        "accent": "#2F5CD8",
        "width": 600,
        "padding": 34,
        "radius": 12,
        "border": 1
    },
    "variables": {}
}
headers = {
    "Authorization": "Bearer <token>",
    "Content-Type": "application/json"
}

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

print(response.text)

const options = {
  method: 'POST',
  headers: {Authorization: 'Bearer <token>', 'Content-Type': 'application/json'},
  body: JSON.stringify({
    blocks: [
      {
        type: 'heading',
        runs: [
          {
            text: '<string>',
            bold: true,
            italic: true,
            color: '<string>',
            href: '<string>'
          }
        ]
      }
    ],
    fromName: '',
    subject: '',
    previewText: '',
    style: {
      pageBackground: '#F4F4F5',
      pagePadding: 32,
      bodyBackground: '#FFFFFF',
      bodyText: '#18181B',
      bodyBorderColor: '#E4E4E7',
      accent: '#2F5CD8',
      width: 600,
      padding: 34,
      radius: 12,
      border: 1
    },
    variables: {}
  })
};

fetch('https://kourio.app/v1/templates/preview', 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://kourio.app/v1/templates/preview",
  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([
    'blocks' => [
        [
                'type' => 'heading',
                'runs' => [
                                [
                                                                'text' => '<string>',
                                                                'bold' => true,
                                                                'italic' => true,
                                                                'color' => '<string>',
                                                                'href' => '<string>'
                                ]
                ]
        ]
    ],
    'fromName' => '',
    'subject' => '',
    'previewText' => '',
    'style' => [
        'pageBackground' => '#F4F4F5',
        'pagePadding' => 32,
        'bodyBackground' => '#FFFFFF',
        'bodyText' => '#18181B',
        'bodyBorderColor' => '#E4E4E7',
        'accent' => '#2F5CD8',
        'width' => 600,
        'padding' => 34,
        'radius' => 12,
        'border' => 1
    ],
    'variables' => [
        
    ]
  ]),
  CURLOPT_HTTPHEADER => [
    "Authorization: Bearer <token>",
    "Content-Type: application/json"
  ],
]);

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

curl_close($curl);

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

package main

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

func main() {

	url := "https://kourio.app/v1/templates/preview"

	payload := strings.NewReader("{\n  \"blocks\": [\n    {\n      \"type\": \"heading\",\n      \"runs\": [\n        {\n          \"text\": \"<string>\",\n          \"bold\": true,\n          \"italic\": true,\n          \"color\": \"<string>\",\n          \"href\": \"<string>\"\n        }\n      ]\n    }\n  ],\n  \"fromName\": \"\",\n  \"subject\": \"\",\n  \"previewText\": \"\",\n  \"style\": {\n    \"pageBackground\": \"#F4F4F5\",\n    \"pagePadding\": 32,\n    \"bodyBackground\": \"#FFFFFF\",\n    \"bodyText\": \"#18181B\",\n    \"bodyBorderColor\": \"#E4E4E7\",\n    \"accent\": \"#2F5CD8\",\n    \"width\": 600,\n    \"padding\": 34,\n    \"radius\": 12,\n    \"border\": 1\n  },\n  \"variables\": {}\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))

}

HttpResponse<String> response = Unirest.post("https://kourio.app/v1/templates/preview")
  .header("Authorization", "Bearer <token>")
  .header("Content-Type", "application/json")
  .body("{\n  \"blocks\": [\n    {\n      \"type\": \"heading\",\n      \"runs\": [\n        {\n          \"text\": \"<string>\",\n          \"bold\": true,\n          \"italic\": true,\n          \"color\": \"<string>\",\n          \"href\": \"<string>\"\n        }\n      ]\n    }\n  ],\n  \"fromName\": \"\",\n  \"subject\": \"\",\n  \"previewText\": \"\",\n  \"style\": {\n    \"pageBackground\": \"#F4F4F5\",\n    \"pagePadding\": 32,\n    \"bodyBackground\": \"#FFFFFF\",\n    \"bodyText\": \"#18181B\",\n    \"bodyBorderColor\": \"#E4E4E7\",\n    \"accent\": \"#2F5CD8\",\n    \"width\": 600,\n    \"padding\": 34,\n    \"radius\": 12,\n    \"border\": 1\n  },\n  \"variables\": {}\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://kourio.app/v1/templates/preview")

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

request = Net::HTTP::Post.new(url)
request["Authorization"] = 'Bearer <token>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"blocks\": [\n    {\n      \"type\": \"heading\",\n      \"runs\": [\n        {\n          \"text\": \"<string>\",\n          \"bold\": true,\n          \"italic\": true,\n          \"color\": \"<string>\",\n          \"href\": \"<string>\"\n        }\n      ]\n    }\n  ],\n  \"fromName\": \"\",\n  \"subject\": \"\",\n  \"previewText\": \"\",\n  \"style\": {\n    \"pageBackground\": \"#F4F4F5\",\n    \"pagePadding\": 32,\n    \"bodyBackground\": \"#FFFFFF\",\n    \"bodyText\": \"#18181B\",\n    \"bodyBorderColor\": \"#E4E4E7\",\n    \"accent\": \"#2F5CD8\",\n    \"width\": 600,\n    \"padding\": 34,\n    \"radius\": 12,\n    \"border\": 1\n  },\n  \"variables\": {}\n}"

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

{
  "data": {
    "fromName": "<string>",
    "subject": "<string>",
    "previewText": "<string>",
    "html": "<string>",
    "text": "<string>",
    "missingVariables": [
      "<string>"
    ],
    "usedVariables": [
      "<string>"
    ],
    "issues": [
      "<string>"
    ]
  }
}

{
  "error": {
    "code": "<string>",
    "message": "<string>",
    "requestId": "<string>",
    "details": [
      {}
    ]
  }
}

{
  "error": {
    "code": "<string>",
    "message": "<string>",
    "requestId": "<string>",
    "details": [
      {}
    ]
  }
}

{
  "error": {
    "code": "<string>",
    "message": "<string>",
    "requestId": "<string>",
    "details": [
      {}
    ]
  }
}