ContactLint vs ZeroBounce, NeverBounce, Kickbox and Bouncer
The decision: do you need to know that a mailbox exists, or do you need to catch bad addresses cheaply before you save or send? ContactLint does the second. It checks syntax, DNS/MX records, disposable domains, role addresses and common typos. It does not connect to mail servers, so it cannot confirm that a mailbox exists or detect catch-all domains.
The short answer
- Choose ContactLint if you want to stop typos, fake domains, throwaway addresses and role inboxes at a signup form, in a CRM import or from an AI agent, at about $1 to $2 per 1,000 checks.
- Choose ZeroBounce, NeverBounce, Kickbox or Bouncer if you are about to email an old or bought list and need each mailbox checked, or you need catch-all detection.
- Switching is not worth it if you already pay for mailbox verification and your volume is small. The saving is a few dollars.
The same job in each: checking one signup email
With ContactLint: send POST /v1/email/validate with {"email": "..."} and your key. The answer comes back in one call with a verdict (valid, risky, invalid or unknown), the MX records it found, the disposable, role and free-provider flags, and a did_you_mean suggestion when the domain looks like a typo of a major provider. A failed DNS lookup returns unknown and the check is given back.
With a mailbox verifier: you send the address to their real-time API and they also test the mailbox, which can catch addresses where the domain is fine but the person does not exist. That extra step is what the higher price pays for. See each vendor's documentation for its exact request and result codes.
Decision table
| Decision | ContactLint | ZeroBounce | NeverBounce | Kickbox | Bouncer |
|---|---|---|---|---|---|
| Checks that the mailbox exists | No. Syntax, DNS/MX, disposable, role and typo checks only | Sold as email validation (pricing) | Sold as email verification (pricing) | Sold as email verification (pricing) | Sold as email verification (pricing) |
| Smallest purchase | 5,000 checks for $9 | $39 for 2,000 (FAQ) | $8 per 1,000 (pricing) | 500 for $5 (tiers) | 1,000 for $8 (FAQ) |
| 5,000 checks, one time | $9 | Not listed | $40 at $8 per 1,000 | $40 | Not listed |
| 100,000 checks, one time | $99 | Not listed | Not listed | $500 | $400 |
| Unknown results charged? | No, when DNS lookup fails the check is given back | No (FAQ) | Not listed | No, credit refunded (pricing) | No (pricing) |
| Credits expire? | No expiry stated in our terms; unused credits refundable within 14 days | Never while on ONE; otherwise rules may apply (FAQ) | 12 months after purchase (pricing) | Not listed | Never (pricing) |
| Free to start | 100 checks per month per key | Not listed on the page we read | Free start offered, amount not listed | 100 free (tiers) | 100 free credits (pricing) |
| Typo suggestions | Yes, did_you_mean for major providers | Not listed | Yes, "gmai to gmail" (pricing) | Not listed | Not listed |
| MCP server for AI agents | Yes, /mcp | Not listed | Not listed | Not listed | Not listed |
| Phone validation on the same key | Yes | Not listed | Not listed | Not listed | Not listed |
Competitor prices read from each vendor's public pricing page on October 16, 2026. Prices change; follow the links for current terms. "Not listed" means the page we read did not state it, not that the vendor lacks it.
One priced scenario: 5,000 signups a month
ContactLint: the first 100 checks each month are free, then one 5,000 pack ($9) covers the rest of the month with checks to spare. Kickbox lists 5,000 verifications at $40 and NeverBounce lists $8 per 1,000, so $40. ZeroBounce's minimum purchase is $39 for 2,000. Bouncer starts at $8 for 1,000. Neither ZeroBounce nor Bouncer listed a 5,000 price on the pages we read.
What switching involves
Get a free key at /signup, replace one HTTP call, and map verdicts: treat invalid as reject, risky as review or ask the user (show did_you_mean), valid as accept, unknown as retry later. You can keep a mailbox verifier for large list cleans and use ContactLint at the form.
How we made this page
Written by the ContactLint team. Competitor facts were read from each vendor's public pricing page on October 16, 2026 and are linked next to each claim; we did not test their APIs. ContactLint facts come from our own pricing page and API spec. We will update this page when prices change.