curl --request POST \
  --url 'https://{domain}/wp-json/sagescreen/v1/wp-admin/admin-ajax.php?nonce=&action=upload_candidates_csv' \
  --header 'Content-Type: multipart/form-data' \
  --form action=upload_candidates_csv \
  --form 'nonce=<string>' \
  --form council_sage_id=123 \
  --form csvUploader='@example-file' \
  --form 'expiration_date=<string>' \
  --form 'email_from=<string>' \
  --form email_from_address=jsmith@example.com \
  --form email_reply_to=jsmith@example.com \
  --form 'email_subject=<string>' \
  --form 'email_header=<string>' \
  --form 'email_body=<string>'

import requests

url = "https://{domain}/wp-json/sagescreen/v1/wp-admin/admin-ajax.php?nonce=&action=upload_candidates_csv"

files = { "csvUploader": ("example-file", open("example-file", "rb")) }
payload = {
    "action": "upload_candidates_csv",
    "nonce": "<string>",
    "council_sage_id": "123",
    "expiration_date": "<string>",
    "email_from": "<string>",
    "email_from_address": "jsmith@example.com",
    "email_reply_to": "jsmith@example.com",
    "email_subject": "<string>",
    "email_header": "<string>",
    "email_body": "<string>"
}

response = requests.post(url, data=payload, files=files)

print(response.text)

const form = new FormData();
form.append('action', 'upload_candidates_csv');
form.append('nonce', '<string>');
form.append('council_sage_id', '123');
form.append('csvUploader', '<string>');
form.append('expiration_date', '<string>');
form.append('email_from', '<string>');
form.append('email_from_address', 'jsmith@example.com');
form.append('email_reply_to', 'jsmith@example.com');
form.append('email_subject', '<string>');
form.append('email_header', '<string>');
form.append('email_body', '<string>');

const options = {method: 'POST'};

options.body = form;

fetch('https://{domain}/wp-json/sagescreen/v1/wp-admin/admin-ajax.php?nonce=&action=upload_candidates_csv', 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://{domain}/wp-json/sagescreen/v1/wp-admin/admin-ajax.php?nonce=&action=upload_candidates_csv",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "POST",
  CURLOPT_POSTFIELDS => "-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"action\"\r\n\r\nupload_candidates_csv\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"nonce\"\r\n\r\n<string>\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"council_sage_id\"\r\n\r\n123\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"csvUploader\"; filename=\"example-file\"\r\nContent-Type: application/octet-stream\r\n\r\n<string>\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"expiration_date\"\r\n\r\n<string>\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"email_from\"\r\n\r\n<string>\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"email_from_address\"\r\n\r\njsmith@example.com\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"email_reply_to\"\r\n\r\njsmith@example.com\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"email_subject\"\r\n\r\n<string>\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"email_header\"\r\n\r\n<string>\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"email_body\"\r\n\r\n<string>\r\n-----011000010111000001101001--",
  CURLOPT_HTTPHEADER => [
    "Content-Type: multipart/form-data"
  ],
]);

$response = curl_exec($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://{domain}/wp-json/sagescreen/v1/wp-admin/admin-ajax.php?nonce=&action=upload_candidates_csv"

	payload := strings.NewReader("-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"action\"\r\n\r\nupload_candidates_csv\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"nonce\"\r\n\r\n<string>\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"council_sage_id\"\r\n\r\n123\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"csvUploader\"; filename=\"example-file\"\r\nContent-Type: application/octet-stream\r\n\r\n<string>\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"expiration_date\"\r\n\r\n<string>\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"email_from\"\r\n\r\n<string>\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"email_from_address\"\r\n\r\njsmith@example.com\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"email_reply_to\"\r\n\r\njsmith@example.com\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"email_subject\"\r\n\r\n<string>\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"email_header\"\r\n\r\n<string>\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"email_body\"\r\n\r\n<string>\r\n-----011000010111000001101001--")

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

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := io.ReadAll(res.Body)

	fmt.Println(string(body))

}

HttpResponse<String> response = Unirest.post("https://{domain}/wp-json/sagescreen/v1/wp-admin/admin-ajax.php?nonce=&action=upload_candidates_csv")
  .body("-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"action\"\r\n\r\nupload_candidates_csv\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"nonce\"\r\n\r\n<string>\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"council_sage_id\"\r\n\r\n123\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"csvUploader\"; filename=\"example-file\"\r\nContent-Type: application/octet-stream\r\n\r\n<string>\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"expiration_date\"\r\n\r\n<string>\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"email_from\"\r\n\r\n<string>\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"email_from_address\"\r\n\r\njsmith@example.com\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"email_reply_to\"\r\n\r\njsmith@example.com\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"email_subject\"\r\n\r\n<string>\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"email_header\"\r\n\r\n<string>\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"email_body\"\r\n\r\n<string>\r\n-----011000010111000001101001--")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://{domain}/wp-json/sagescreen/v1/wp-admin/admin-ajax.php?nonce=&action=upload_candidates_csv")

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

request = Net::HTTP::Post.new(url)
request.body = "-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"action\"\r\n\r\nupload_candidates_csv\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"nonce\"\r\n\r\n<string>\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"council_sage_id\"\r\n\r\n123\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"csvUploader\"; filename=\"example-file\"\r\nContent-Type: application/octet-stream\r\n\r\n<string>\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"expiration_date\"\r\n\r\n<string>\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"email_from\"\r\n\r\n<string>\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"email_from_address\"\r\n\r\njsmith@example.com\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"email_reply_to\"\r\n\r\njsmith@example.com\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"email_subject\"\r\n\r\n<string>\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"email_header\"\r\n\r\n<string>\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"email_body\"\r\n\r\n<string>\r\n-----011000010111000001101001--"

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