isDisposable vs Kickbox
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. Kickbox is a paid service focused on deliverability verification. Here's an honest breakdown.
What is Kickbox?
Kickbox is a paid email verification service focused on deliverability. It verifies whether a mailbox actually exists via SMTP checks, scores list quality, and integrates with major ESPs to reduce bounce rates.
Feature comparison
| Feature | isDisposable | Kickbox |
|---|---|---|
| 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 npm/PyPI package — disposable detection runs offline with zero API calls.
- Free to start; no per-verification billing for the bundled blocklist.
- One-line synchronous check, ideal for blocking fake signups at the form.
- 160,000+ disposable domains bundled and continuously updated.
Where Kickbox wins
- Full SMTP-level mailbox verification — confirms an address can actually receive mail.
- Mature bulk list-cleaning workflow for marketing teams.
- Deliverability-focused scoring (Sendex) and ESP integrations.
Which should you choose?
Choose Kickbox if you are cleaning large marketing lists and need to confirm each mailbox is real and deliverable before a send.
Choose isDisposable if you want to block disposable and fake signups in real time, for free, without sending every signup to a third-party API. Many teams use both — isDisposable at the signup form, Kickbox 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 Kickbox?
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 Kickbox do that isDisposable does not?
Full SMTP-level mailbox verification — confirms an address can actually receive mail.
Should I switch from Kickbox to isDisposable?
If your goal is blocking disposable and fake signups, you want to block disposable and fake signups in real time, for free, without sending every signup to a third-party API. If you are cleaning large marketing lists and need to confirm each mailbox is real and deliverable before a send., Kickbox 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.