A Kickbox alternative built for developers
MailRambo verifies email addresses with one API call and answers with a strict yes/no plus the reason. Catch-alls and unverifiable mailboxes count as no, so bad addresses never reach your sender reputation.
Why switch from Kickbox
- 10,000 verifications for $29 instead of $70.
- A free allowance every month (50) instead of a one-time 100.
- SPF, DKIM, DMARC and domain grade in the same call with ?detail=full.
What you get with MailRambo
- 100 free verifications every month, with the API on every plan including Free.
- Plans from $5/month for 1,000 checks, or packs from $9 that never expire.
- Free instant checks for signup forms:
mode=fastcatches typos, disposable domains and domains with no mail server in under a second, at no cost. - Free repeats: checking the same address again within 24 hours costs nothing.
- Free test keys (
mr_test_) return canned answers so you can build without spending credits. - Domain intelligence: add
?detail=fullfor grade, SPF, DKIM, DMARC, BIMI and PTR in the same call. - Developer basics done right: public OpenAPI spec, Idempotency-Key on batches, refunds when the provider fails.
At a glance
| MailRambo | Kickbox | |
|---|---|---|
| Free tier | 100 verifications every month, API included | 100 free verifications (one-time) |
| Entry price | $5/mo for 1,000, or $9 for 2,000 (never expire) | $5 for 500; $10 for 1,000 |
| ~10,000 verifications | $29 for 10,000 (never expire) | $70 for 10,000 |
| Credit expiry | Pack credits never expire | Check their site |
| Catch-all addresses | Answered as not deliverable (reason: catch_all) | Check their site |
| API answer format | Strict yes/no + reason code | Check their site |
| Free test / sandbox mode | Yes - free mr_test_ keys with canned answers | Check their site |
| Public OpenAPI spec | Yes - public /v1/openapi.json | Check their site |
| Domain auth data (SPF/DKIM/DMARC) | Yes - SPF, DKIM, DMARC, BIMI, PTR via ?detail=full | Check their site |
| Retry-safe batch requests | Yes - Idempotency-Key on batches | Check their site |
| Free instant check for signup forms | Yes - mode=fast: free, under 1s (syntax, typos, MX, disposable) | Check their site |
| Free repeat checks | Yes - same address within 24h is free | Check their site |
Kickbox details from their pricing page, checked September 2026. Prices change; confirm on their site.
Kickbox is still a good choice if SOC 2 compliance paperwork is a hard requirement for your procurement process today.
Switching from Kickbox
Point your code at /v1/verify and map Kickbox's results to a single boolean:
| Kickbox result | MailRambo |
|---|---|
deliverable | deliverable: true |
undeliverable | false (mailbox_not_found) |
risky (accept_all) | false (catch_all) |
unknown | false (unverifiable) |
const res = await fetch("https://www.mailrambo.com/v1/verify", {
method: "POST",
headers: {
Authorization: `Bearer ${process.env.MAILRAMBO_KEY}`,
"Content-Type": "application/json",
},
body: JSON.stringify({ email }),
});
const { deliverable, reason } = await res.json();
if (!deliverable) reject(reason); // "catch_all", "disposable", "mailbox_not_found", ...Build it with a free mr_test_ key first - no credits used. API reference · OpenAPI spec
Frequently asked questions
Is MailRambo cheaper than Kickbox?
For most volumes, yes. MailRambo starts at $5/month for 1,000 verifications, and 10,000 costs $29 as a pack that never expires. Check Kickbox's pricing page for their current rates; we last checked in September 2026.
How do I migrate from Kickbox to MailRambo?
Swap the endpoint and map Kickbox's statuses to MailRambo's deliverable true/false. Most integrations take under an hour, and free test keys let you try it without spending credits.
How does MailRambo handle catch-all addresses?
They count as not deliverable, with reason catch_all. Catch-all servers accept every address during the check, so the mailbox can't be confirmed and many of those messages bounce later.
Is there a free plan?
Yes: 100 verifications every month, with full API access and free test keys.
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Run these checks from your code
Verify addresses at signup, clean lists and read SPF/DKIM/DMARC with one API call. 100 free verifications a month, test keys that cost nothing, and the API on every plan.