@isdisposable/js

Stop fake signups. One line of code.

Open-source email validation that catches disposable emails before they waste your time. 161,000+ domains. Zero dependencies.

Install

npm install @isdisposable/js

Quick Start

import { isDisposable } from '@isdisposable/js';

isDisposable('[email protected]'); // true
isDisposable('[email protected]');      // false

That's it. Synchronous, offline, zero config.

Bulk Check

import { isDisposableBulk } from '@isdisposable/js';

isDisposableBulk(['[email protected]', '[email protected]']);
// [true, false]

Why isDisposable?

| Feature | isDisposable | mailchecker | disposable-email-domains | |---------|-------------|-------------|--------------------------| | Domains | 161,000+ | 55,000 | 5,000 | | Simple boolean API | Yes | Yes | No (just a list) | | Zero dependencies | Yes | No | N/A | | TypeScript | Yes | Partial | N/A | | Hosted API with scoring | Yes | No | No | | Actively maintained | Yes | Sporadic | Sporadic |

Framework Examples

Next.js Server Action

'use server';
import { isDisposable } from '@isdisposable/js';

export async function signup(formData: FormData) {
  const email = formData.get('email') as string;

  if (isDisposable(email)) {
    return { error: 'Please use a real email address' };
  }

  // Continue with signup...
}

Express Middleware

import express from 'express';
import { isDisposable } from '@isdisposable/js';

const app = express();
app.use(express.json());

app.post('/signup', (req, res, next) => {
  if (isDisposable(req.body.email)) {
    return res.status(400).json({ error: 'Please use a real email address' });
  }
  next();
});

Better Auth Integration

import { betterAuth } from 'better-auth';
import { isDisposable } from '@isdisposable/js';

export const auth = betterAuth({
  databaseHooks: {
    user: {
      create: {
        before: async (user) => {
          if (isDisposable(user.email)) {
            return false; // Block signup
          }
          return user;
        },
      },
    },
  },
});

Supabase Edge Function

import { isDisposable } from '@isdisposable/js';

Deno.serve(async (req) => {
  const { email } = await req.json();

  if (isDisposable(email)) {
    return new Response(
      JSON.stringify({ error: 'Disposable emails not allowed' }),
      { status: 400, headers: { 'Content-Type': 'application/json' } }
    );
  }

  return new Response(JSON.stringify({ ok: true }));
});

API Mode (Enhanced Detection)

For real-time DNS/MX checks, risk scoring (0-100), and domain age analysis, use the hosted API:

import { createIsDisposable } from '@isdisposable/js';

const checker = createIsDisposable({
  apiKey: 'isd_live_xxxxx', // Get one at https://isdisposable.com
});

const result = await checker.check('[email protected]');
// {
//   disposable: true,
//   email: "[email protected]",
//   domain: "mailinator.com",
//   score: 95,
//   reason: "blocklist_match",
//   mx_valid: true,
//   domain_age_days: 4380,
//   cached: false
// }

// Bulk check (up to 100 emails)
const results = await checker.checkBulk([
  '[email protected]',
  '[email protected]',
]);

The API client automatically falls back to offline detection if the API is unreachable.

How It Works

1. Offline mode (default): Checks against a bundled blocklist of 161,000+ known disposable email domains. Instant, synchronous, zero network calls.

2. API mode (optional): Adds real-time DNS/MX record validation, domain age checks via RDAP, and a composite risk score from 0-100. Requires an API key from isdisposable.com.

API

isDisposable(email: string): boolean

Synchronous check. Returns true if the email domain is disposable.

isDisposableBulk(emails: string[]): boolean[]

Synchronous bulk check. Returns array of booleans.

isDomainDisposable(domain: string): boolean

Check a domain directly (without an email address).

createIsDisposable(config): ApiClient

Create an API client for enhanced detection.

Config options:

| Option | Type | Default | Description | |--------|------|---------|-------------| | apiKey | string | — | Your API key from isdisposable.com | | apiUrl | string | https://isdisposable.com | API base URL | | timeout | number | 5000 | Request timeout in ms | | cache | boolean | true | Enable response caching | | cacheTTL | number | 3600 | Cache TTL in seconds |

Contributing

Found a domain that should be blocked? Open an issue or PR on the GitHub repo with the domain name. We review and update the blocklist regularly.

License

MIT

Built by Junaid Shaukat. Dashboard and API at isdisposable.com.

Part of the isDisposable ecosystem. feedback and contact here --> [email protected]