React Native
Mailgun Send Send HTML Email with Attachments and HTML Images

Sends an HTML email with images and attachments.
Chilkat React Native Downloads

React Native
import { BinData, Http, HttpRequest, HttpResponse, JsonObject, StringBuilder } from '@chilkat/react-native'

async function chilkatExample() {
  // This example assumes the Chilkat API to have been previously unlocked.
  // See Global Unlock Sample for sample code.

  const http = new Http();

  http.login = 'api';
  http.password = 'sending_api_key';  // Replace with your actual sending API key.

  const req = new HttpRequest();
  req.httpVerb = 'POST';
  req.path = '/v3/YOUR_DOMAIN_NAME/messages';
  req.contentType = 'multipart/form-data';

  // Change YOUR_DOMAIN_NAME to something like "mg.your-domain.com".
  req.addParam('from', 'Your Name <mailgun@YOUR_DOMAIN_NAME>');
  req.addParam('to', 'Joe Example <joe@example.com>');
  req.addParam('subject', 'Hello Joe Example');
  req.addParam('html', '<html><body><b>This is the HTML body</b><br><img src="cid:cidStarfish.jpg"></body></html>');

  // An a attachd file
  const bd = new BinData();
  try {
    bd.loadFile('qa_data/hamlet.zip');
  } catch {
    console.log('Failed to load file attachment.');
    return;
  }

  req.addBdForUpload('attachment', 'hamlet.zip', bd, 'application/zip');

  // add an image as CID
  try {
    bd.loadFile('qa_data/jpg/starfish.jpg');
  } catch {
    console.log('Failed to load HTML image.');
    return;
  }

  req.addBdForUpload('inline', 'cidStarfish.jpg', bd, 'image/jpeg');

  const resp = new HttpResponse();
  try {
    await http.httpSReqAsync('api.mailgun.net', 443, true, req, resp);
  } catch {
    console.log(http.lastErrorText);
    return;
  }

  const sbResponseBody = new StringBuilder();
  resp.getBodySb(sbResponseBody);
  const jResp = new JsonObject();
  jResp.loadSb(sbResponseBody);
  jResp.emitCompact = false;

  console.log('Response Body:');
  console.log(jResp.emit());

  const respStatusCode = resp.statusCode;
  console.log(`Response Status Code = ${respStatusCode}`);
  if (respStatusCode >= 400) {
    console.log('Response Header:');
    console.log(resp.header);
    console.log('Failed.');
    return;
  }

  // Sample JSON response:
  // (Sample code for parsing the JSON response is shown below)

  // {
  //   "id": "<20210429234809.1.2D550E1C94D3D98F@sandbox0e542e4c577f4bbb98c8bf6b6bca727b.mailgun.org>",
  //   "message": "Queued. Thank you."
  // }

  // Sample code for parsing the JSON response...
  // Use the following online tool to generate parsing code from sample JSON:
  // Generate Parsing Code from JSON

  const id = jResp.stringOf('id');
  const message = jResp.stringOf('message');
}