curl --request POST \
  --url https://api.everhour.com/resource-planner/assignments \
  --header 'Content-Type: application/json' \
  --header 'X-Api-Key: <api-key>' \
  --data '
{
  "startDate": "2019-01-21",
  "endDate": "2019-02-01",
  "user": 79786,
  "project": "as:981141080110246",
  "task": "<string>",
  "client": 123,
  "type": "project",
  "time": 252000,
  "note": "<string>",
  "includeWeekends": true,
  "color": "<string>",
  "sendNotification": true,
  "forceOverride": true,
  "timeOffType": "<string>",
  "users": [
    79786,
    80012
  ],
  "reviewer": 123
}
'

import requests

url = "https://api.everhour.com/resource-planner/assignments"

payload = {
    "startDate": "2019-01-21",
    "endDate": "2019-02-01",
    "user": 79786,
    "project": "as:981141080110246",
    "task": "<string>",
    "client": 123,
    "type": "project",
    "time": 252000,
    "note": "<string>",
    "includeWeekends": True,
    "color": "<string>",
    "sendNotification": True,
    "forceOverride": True,
    "timeOffType": "<string>",
    "users": [79786, 80012],
    "reviewer": 123
}
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({
    startDate: '2019-01-21',
    endDate: '2019-02-01',
    user: 79786,
    project: 'as:981141080110246',
    task: '<string>',
    client: 123,
    type: 'project',
    time: 252000,
    note: '<string>',
    includeWeekends: true,
    color: '<string>',
    sendNotification: true,
    forceOverride: true,
    timeOffType: '<string>',
    users: [79786, 80012],
    reviewer: 123
  })
};

fetch('https://api.everhour.com/resource-planner/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.everhour.com/resource-planner/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([
    'startDate' => '2019-01-21',
    'endDate' => '2019-02-01',
    'user' => 79786,
    'project' => 'as:981141080110246',
    'task' => '<string>',
    'client' => 123,
    'type' => 'project',
    'time' => 252000,
    'note' => '<string>',
    'includeWeekends' => true,
    'color' => '<string>',
    'sendNotification' => true,
    'forceOverride' => true,
    'timeOffType' => '<string>',
    'users' => [
        79786,
        80012
    ],
    'reviewer' => 123
  ]),
  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;
}

package main

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

func main() {

	url := "https://api.everhour.com/resource-planner/assignments"

	payload := strings.NewReader("{\n  \"startDate\": \"2019-01-21\",\n  \"endDate\": \"2019-02-01\",\n  \"user\": 79786,\n  \"project\": \"as:981141080110246\",\n  \"task\": \"<string>\",\n  \"client\": 123,\n  \"type\": \"project\",\n  \"time\": 252000,\n  \"note\": \"<string>\",\n  \"includeWeekends\": true,\n  \"color\": \"<string>\",\n  \"sendNotification\": true,\n  \"forceOverride\": true,\n  \"timeOffType\": \"<string>\",\n  \"users\": [\n    79786,\n    80012\n  ],\n  \"reviewer\": 123\n}")

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

	req.Header.Add("X-Api-Key", "<api-key>")
	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://api.everhour.com/resource-planner/assignments")
  .header("X-Api-Key", "<api-key>")
  .header("Content-Type", "application/json")
  .body("{\n  \"startDate\": \"2019-01-21\",\n  \"endDate\": \"2019-02-01\",\n  \"user\": 79786,\n  \"project\": \"as:981141080110246\",\n  \"task\": \"<string>\",\n  \"client\": 123,\n  \"type\": \"project\",\n  \"time\": 252000,\n  \"note\": \"<string>\",\n  \"includeWeekends\": true,\n  \"color\": \"<string>\",\n  \"sendNotification\": true,\n  \"forceOverride\": true,\n  \"timeOffType\": \"<string>\",\n  \"users\": [\n    79786,\n    80012\n  ],\n  \"reviewer\": 123\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://api.everhour.com/resource-planner/assignments")

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

request = Net::HTTP::Post.new(url)
request["X-Api-Key"] = '<api-key>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"startDate\": \"2019-01-21\",\n  \"endDate\": \"2019-02-01\",\n  \"user\": 79786,\n  \"project\": \"as:981141080110246\",\n  \"task\": \"<string>\",\n  \"client\": 123,\n  \"type\": \"project\",\n  \"time\": 252000,\n  \"note\": \"<string>\",\n  \"includeWeekends\": true,\n  \"color\": \"<string>\",\n  \"sendNotification\": true,\n  \"forceOverride\": true,\n  \"timeOffType\": \"<string>\",\n  \"users\": [\n    79786,\n    80012\n  ],\n  \"reviewer\": 123\n}"

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

{
  "days": 10,
  "endDate": "2019-02-01",
  "id": 41827,
  "project": "as:981141080110246",
  "startDate": "2019-01-21",
  "time": 252000,
  "type": "project",
  "user": 79786
}