Best email verifiers for SaaS signups
Fake signups come from throwaway domains, typos and made-up addresses. Eight verifiers ranked on signup-time checks, flags returned and cost per check.
How this was compared
Disclosure: ZapBounce is our product. Figures were read from each vendor's own pages in September 2026, and the criteria below were applied to every entry, ours included.
The short version
- What one call returns at signup: the mailbox result plus separate flags for disposable, role and free-provider addresses.
- A typo suggestion, so a real user who typed gmial.com is asked to fix it instead of being turned away.
- A test mode that never bills, so your engineers can wire the form without spending credits.
- Billing for unknown results, since a signup check runs on every form submit.
- Free allowance and published price per check, read from each vendor's own pages in September 2026.
- Disclosure: ZapBounce is our product, and the same criteria were applied to it.
At a glance
| 10,000 addresses | Credit expiry | Bills unknowns | |
|---|---|---|---|
| ZapBounce | $25 | Credits never expire | No |
| Xverify | $70 | Not stated anywhere we could find | No |
| Kickbox | $70 | Credits expire one year from purchase | No |
| Verifalia | $49.90 at Standard quality | Purchased credits never expire; daily free credits expire each day | Not stated |
| EmailHippo | Behind their pricing calculator | Not on their public pages | Not stated |
| QuickEmailVerification | $60 one-time | One-time credits never expire; daily subscription credits reset and do not roll over | No |
| ZeroBounce | Subscription only | Credits roll over while the subscription is active | Not stated |
| Emailable | $0.0076 an address at the 5,000 entry, 15% off on a subscription | Credits never expire | No |
Vendor figures read from their own pricing pages in September 2026. Confirm before purchase, because prices move.
The ranking
Best first, with the situation each one fits.
ZapBounce
Disclosure: ZapBounce is our product. Your backend sends the address to POST /v1/verify and gets back valid, invalid, catch_all or unknown, plus disposable, role and free_provider flags and a did_you_mean suggestion. The disposable flag reads an open-source domain list merged with our own additions and refreshed weekly.
- Best for:
- SaaS teams that want to block throwaway domains and catch typos at the form, with 100 free checks a month and sandbox keys that never bill. See the API reference and the signup validation guide.
Xverify
Xverify aims its real-time validation at lead generation and form fraud, and runs a fresh lookup on every request rather than serving a cached answer.
- Best for:
- Lead-generation forms that also validate phone numbers and postal addresses.
- Less suited to:
- Long free testing, since its free allowance is 100 verifications, one time.
Kickbox
Kickbox refunds unknowns and adds a Sendex quality score to each address. Its 10,000 tier costs $70, read on kickbox.com on 24 September 2026.
- Best for:
- Teams that want a quality score to weigh a signup, not only a result.
- Less suited to:
- Credits bought ahead of a launch, since they expire one year from purchase.
Verifalia
Verifalia reports why an address failed and sells three check depths that cost 1, 2 and 4 credits an address.
- Best for:
- Developers who want to choose how hard each check pushes.
- Less suited to:
- High-volume forms on a small free allowance, which is 25 checks a day and resets at midnight GMT.
EmailHippo
EmailHippo is a British verification business with ISO 27001 behind it, and it sells fraud scoring as a separate product above verification.
- Best for:
- Teams buying fraud scoring and verification from one vendor.
- Less suited to:
- Buyers who want a volume price on the page, since volume sits behind a calculator.
QuickEmailVerification
QuickEmailVerification gives 100 free credits a day and states plainly that it does not charge for unknowns.
- Best for:
- Low-traffic signup forms that fit inside a daily free allowance.
- Less suited to:
- Rolling unused daily credits forward, since daily subscription credits reset.
ZeroBounce
ZeroBounce pairs verification with inbox placement, blacklist monitoring and activity data.
- Best for:
- Teams that want signup checks and deliverability tools on one account.
- Less suited to:
- Pay-as-you-go at 10,000 checks, which ZeroBounce sells as a subscription only.
Emailable
Emailable refunds duplicates and unknowns, and its credits never expire.
- Best for:
- Products with steady signup volume that buy credits in bulk.
- Less suited to:
- Early-stage products, since purchases start at 5,000 credits.
Why ZapBounce ranks first
How to choose
- Flags returned: ZapBounce returns disposable, role and free_provider as separate flags beside the result, so you can block throwaway domains and still accept a Gmail signup. Decide which flags your form acts on before you compare prices.
- Free allowance: Verifalia gives 25 checks a day and Xverify 100 once (read September 2026). ZapBounce gives 100 free checks every month with no card.
- Credit expiry: Kickbox credits expire one year from purchase (read 24 September 2026). ZapBounce credits never expire, so a slow month does not waste what you bought.
- Entry cost: Emailable starts at 5,000 credits. ZapBounce starts at $5 for 1,000, so a small launch buys only the checks it needs.
Questions people ask
How do I stop fake signups on a SaaS trial?
Check each address when the form is submitted, before the account is created. Block invalid results and disposable domains, ask the user to fix a suggested typo, and keep your email confirmation step for everyone else. ZapBounce returns all of that in one POST /v1/verify call.
Should I block free email providers like Gmail at signup?
Only if you sell to companies and want a work address. ZapBounce returns free_provider as a flag, so you choose per form whether to block, warn or accept.
What does a signup check cost?
ZapBounce charges $5 per 1,000 checks, $25 for 10,000, and gives 100 free checks a month. Unknown results and sandbox calls are never billed.
Does verification replace email confirmation?
No. Verification tells you the mailbox exists before you create the account, and confirmation proves the person signing up can read it. Run the check first and keep the confirmation email.
Run the same sample through two of them
100 free checks a month, no card. Compare how many addresses each one declined to judge, which matters more than either accuracy claim.