NexMailPro JavaScript SDK

Official standalone JavaScript and TypeScript SDK for the NexMailPro email verification API.

Features

• TypeScript-first API with full typings
• Browser and Node.js support
• ESM and CommonJS builds
• Zero runtime dependencies
• Typed API and transport errors
• Single email verification plus bulk verification helpers

Installation

npm install @nexmailpro/sdk

Requirements

• Node.js 18+ for native fetch
• Any modern browser with the Fetch API
• Older Node.js runtimes can work if you pass a custom fetch implementation

Quick Start

import { NexMailProClient } from "@nexmailpro/sdk";

const client = new NexMailProClient({
  apiKey: 'YOUR_API_KEY',
});

const result = await client.verifyEmail('[email protected]');

console.log(result.data.status);
console.log(result.meta?.credits_charged);

CommonJS

const { NexMailProClient } = require('@nexmailpro/sdk');

const client = new NexMailProClient({
  apiKey: process.env.NEXMAILPRO_API_KEY,
});

client.verifyEmail('[email protected]').then((result) => {
  console.log(result.data);
});

Browser Use

The SDK works in browsers, but long-lived API keys should only be used in trusted environments such as internal tools, browser extensions, or apps that proxy requests through your backend.

A runnable browser example is included in examples/browser/index.html.

API

new NexMailProClient(options)

interface NexMailProOptions {
  apiKey: string;
  baseUrl?: string;
  timeoutMs?: number;
  headers?: HeadersInit;
  fetch?: typeof fetch;
  userAgent?: string;
}

Defaults:

• baseUrl: https://nexmailpro.com
• timeoutMs: 15000

verifyEmail(email, payload?, requestOptions?)

Verifies a single email by calling:

POST https://nexmailpro.com/api/v1/verify/email

const response = await client.verifyEmail('[email protected]', {
  source: 'signup-form',
});

Response shape:

{
  success: true,
  message: 'Verification completed',
  data: {
    email: '[email protected]',
    status: 'valid',
    sub_status: 'deliverable',
    score: 90,
    is_syntax_valid: true,
    has_mx: true,
    domain_exists: true
  },
  meta: {
    credits_charged: 1
  }
}

Bulk Helpers

The SDK also exposes typed wrappers for the currently documented bulk endpoints:

• createBulkVerification(input)
• getBulkVerificationStatus(uuid)
• startBulkVerification(uuid)
• getBulkVerificationResults(uuid, query?)

Examples:

const bulk = await client.createBulkVerification({
  title: 'May newsletter',
  emails: ['[email protected]', '[email protected]'],
  smtpMode: 'safe',
});

const status = await client.getBulkVerificationStatus(bulk.data.uuid);

CSV uploads are supported with Blob, File, Uint8Array, ArrayBuffer, or raw CSV strings.

Error Handling

import {
  NexMailProClient,
  NexMailProApiError,
  NexMailProTransportError,
} from '@nexmailpro/sdk';

try {
  await client.verifyEmail('bad-email');
} catch (error) {
  if (error instanceof NexMailProApiError) {
    console.error(error.status, error.code, error.response);
  } else if (error instanceof NexMailProTransportError) {
    console.error(error.message);
  }
}

Examples

• examples/node-esm.mjs
• examples/node-cjs.cjs
• examples/browser/index.html

Development

npm install
npm run build
npm test
npm pack

License

MIT