curl --request POST \
  --url https://{your-subdomain}.neetoinvoice.com/api/external/v1/projects/{project_id}/project_users \
  --header 'Content-Type: application/json' \
  --header 'X-Api-Key: <x-api-key>' \
  --data '
{
  "project_user": {
    "user_id": "5a2de667-243b-4da3-b090-b698a03d98da",
    "role": "regular_user",
    "hourly_rate": 75.5
  },
  "email": "john@example.com"
}
'

import requests

url = "https://{your-subdomain}.neetoinvoice.com/api/external/v1/projects/{project_id}/project_users"

payload = {
    "project_user": {
        "user_id": "5a2de667-243b-4da3-b090-b698a03d98da",
        "role": "regular_user",
        "hourly_rate": 75.5
    },
    "email": "john@example.com"
}
headers = {
    "X-Api-Key": "<x-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': '<x-api-key>', 'Content-Type': 'application/json'},
  body: JSON.stringify({
    project_user: {
      user_id: '5a2de667-243b-4da3-b090-b698a03d98da',
      role: 'regular_user',
      hourly_rate: 75.5
    },
    email: 'john@example.com'
  })
};

fetch('https://{your-subdomain}.neetoinvoice.com/api/external/v1/projects/{project_id}/project_users', 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://{your-subdomain}.neetoinvoice.com/api/external/v1/projects/{project_id}/project_users",
  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([
    'project_user' => [
        'user_id' => '5a2de667-243b-4da3-b090-b698a03d98da',
        'role' => 'regular_user',
        'hourly_rate' => 75.5
    ],
    'email' => 'john@example.com'
  ]),
  CURLOPT_HTTPHEADER => [
    "Content-Type: application/json",
    "X-Api-Key: <x-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://{your-subdomain}.neetoinvoice.com/api/external/v1/projects/{project_id}/project_users"

	payload := strings.NewReader("{\n  \"project_user\": {\n    \"user_id\": \"5a2de667-243b-4da3-b090-b698a03d98da\",\n    \"role\": \"regular_user\",\n    \"hourly_rate\": 75.5\n  },\n  \"email\": \"john@example.com\"\n}")

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

	req.Header.Add("X-Api-Key", "<x-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://{your-subdomain}.neetoinvoice.com/api/external/v1/projects/{project_id}/project_users")
  .header("X-Api-Key", "<x-api-key>")
  .header("Content-Type", "application/json")
  .body("{\n  \"project_user\": {\n    \"user_id\": \"5a2de667-243b-4da3-b090-b698a03d98da\",\n    \"role\": \"regular_user\",\n    \"hourly_rate\": 75.5\n  },\n  \"email\": \"john@example.com\"\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://{your-subdomain}.neetoinvoice.com/api/external/v1/projects/{project_id}/project_users")

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

request = Net::HTTP::Post.new(url)
request["X-Api-Key"] = '<x-api-key>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"project_user\": {\n    \"user_id\": \"5a2de667-243b-4da3-b090-b698a03d98da\",\n    \"role\": \"regular_user\",\n    \"hourly_rate\": 75.5\n  },\n  \"email\": \"john@example.com\"\n}"

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

{
  "project_user": {
    "id": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
    "user_id": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
    "role": "<string>",
    "hourly_rate": 123,
    "name": "<string>",
    "email": "jsmith@example.com",
    "time_zone": "<string>"
  }
}