isDisposable vs NeverBounce
Both detect disposable email addresses — but they solve different problems. isDisposable is an open-source library and API for blocking fake signups in real time. NeverBounce is a paid service focused on deliverability verification. Here's an honest breakdown.
What is NeverBounce?
NeverBounce is a paid email verification service focused on bulk list cleaning and real-time mailbox verification. It confirms whether an address can receive mail and is used mainly by sales and marketing teams to cut bounce rates.
Feature comparison
| Feature | isDisposable | NeverBounce |
|---|---|---|
| Open source | ||
| Free tier | ||
| Offline / self-hosted check | ||
| No API key required (npm package) | ||
| Disposable / temporary email detection | ||
| Real-time MX / DNS checks | ||
| Full mailbox (SMTP) deliverability verification | ||
| Risk / confidence score | ||
| Bulk list cleaning |
full · partial · not available
Where isDisposable wins
- Open-source package — disposable detection runs offline, no API call per signup.
- Free to start; no per-verification credits for the bundled blocklist.
- Synchronous, dependency-free check built for the signup form.
- 160,000+ disposable domains bundled and continuously updated.
Where NeverBounce wins
- Bulk list cleaning at scale with deliverability guarantees.
- Real-time SMTP verification confirming a mailbox exists.
- Integrations with CRMs and marketing platforms.
Which should you choose?
Choose NeverBounce if you need to clean large contact lists and guarantee deliverability before a campaign.
Choose isDisposable if you want to block disposable signups in real time, for free, with code you control. Many teams use both — isDisposable at the signup form, NeverBounce for periodic list cleaning.
Try isDisposable in 60 seconds
npm install @isdisposable/jsimport { isDisposable } from '@isdisposable/js';
if (isDisposable(email)) {
throw new Error('Please use a permanent email address');
}Frequently asked questions
Is isDisposable a free alternative to NeverBounce?
Yes. isDisposable is open source. The npm and PyPI packages bundle 160,073+ disposable domains and run offline for free. A paid API tier adds live DNS checks and scoring, with a free plan to start.
What does NeverBounce do that isDisposable does not?
Bulk list cleaning at scale with deliverability guarantees.
Should I switch from NeverBounce to isDisposable?
If your goal is blocking disposable and fake signups, you want to block disposable signups in real time, for free, with code you control. If you need to clean large contact lists and guarantee deliverability before a campaign., NeverBounce remains a strong fit — the two tools also work well together.
Start blocking disposable signups
Free, open-source, and live in one line of code.