Pro API Waitlist Now Open

Block fake signups in one line of code.

Detect and block disposable & temporary emails before they waste your AI credits, trial slots, and compute. Open-source npm package + real-time API. 150,000+ domains. Works offline.

$npm install @isdisposable/js

Join the waitlist for early access to the Pro API & analytics.

Every SaaS product has the same problem.

Fake users sign up with throwaway emails from services like Guerrilla Mail, 10MinuteMail, and Mailinator. They burn through your free tier, waste your AI credits, inflate your metrics, and never convert.

isDisposable stops them before they get in.

user_8912@guerrillamail.comBlocked
temp-guy@10minutemail.comBlocked
sarah.jenkins@acmecorp.comAllowed
throwaway123@mailinator.comBlocked

How it works

The open-source package ships with 150,000+ known disposable email domains and works completely offline — zero API calls, zero latency, zero cost.

Install the package

Drop-in npm package for any Node.js, Next.js, or Express project.

npm install @isdisposable/js

Add one line

Call the function in your signup flow before creating the user.

if (isDisposable(email)) throw new Error()

Fake signups blocked

Real users only. Instantly save money on compute and API calls.

Simple. Fast. Elegant.

One function, one line, returns a boolean. No config, no API key, no async, no setup. It works offline with the bundled 150k+ domain list.

basic.ts
import { isDisposable } from '@isdisposable/js';

isDisposable('test@mailinator.com');  // true
isDisposable('user@gmail.com');       // false
bulk.ts
// For bulk processing:
import { isDisposableBulk } from '@isdisposable/js';

isDisposableBulk([
'a@tempmail.com',
'b@gmail.com'
]); // [true, false]
For teams that need more

The Pro API

Catch domains that aren't on any static list yet. Real-time detection of NEW disposable services using advanced DNS analysis and risk scoring.

Real-time Detection

MX record fingerprinting catches new throwaway services instantly.

Risk Scoring (0-100)

Granular control over who gets access to your premium features.

Analytics Dashboard

See exactly how many fake signups were blocked and money saved.

Request early access