Teams look for Kickbox alternatives when they want a lower price per address at monthly volume, a bulk API with webhooks, or prices published as fixed monthly plans. This page compares Kickbox with emailvalidation.io and lists other options. Competitor facts come from each vendor’s own pricing page, documentation or official code libraries, checked October 10–11, 2026.
Disclosure: we make emailvalidation.io, one of the alternatives on this page. Kickbox’s strengths are listed in their own section, and the sources are at the end.
Kickbox pricing (checked October 2026)
Kickbox sells pay-as-you-go verification credits. Its pricing page lists:
| Verifications | Price | Per address |
|---|---|---|
| 100 | Free | – |
| 500 | $5 | $0.01 |
| 1,000 | $10 | $0.01 |
| 2,500 | $25 | $0.01 |
| 5,000 | $40 | $0.008 |
| 10,000 | $70 | $0.007 |
| 25,000 | $150 | $0.006 |
| 50,000 | $275 | $0.0055 |
| 100,000 | $500 | $0.005 |
| 250,000 | $1,100 | $0.0044 |
| 500,000 | $1,800 | $0.0036 |
| 1,000,000 | $2,999 | $0.003 |
| More than 1 million | Custom pricing or volume discounts | – |
What else the pricing page and libraries say:
- Unknown results: if Kickbox can’t give a definitive result, it refunds the credit.
- Where it runs: verification and support are based in the US and the EU; Kickbox says it is GDPR-compliant and SOC 2 certified.
- Account: you “create a free account” to get an API key.
- Balance: every API response carries an
X-Kickbox-Balanceheader with your remaining credits, counted as “Daily + On Demand”.
Quick verdict
- Stay with Kickbox if your code already uses its
sendexquality score andreasonvalues, or if you want an official library for PHP, Node.js, Ruby or Python with a per-request timeout. - Choose emailvalidation.io if you verify every month through an API or in lists and want fixed monthly prices: $9.99 for 5,000 checks instead of $40 in Kickbox credits, and $94.99 for 100,000 instead of $500.
- Choose a credit-pack verifier such as Bouncer or MillionVerifier for one big list now and then, paid with credits that don’t expire.
Kickbox vs. emailvalidation.io side by side
| Row label | Kickbox | emailvalidation.io |
|---|---|---|
| 5,000 checks | $40 (credits) | $9.99 / month (Small) |
| 25,000 checks | $150 (credits) | $34.99 / month (Medium) |
| 100,000 checks | $500 (credits) | $94.99 / month (Large) |
| Price model | Pay-as-you-go credits; unknown results refunded | Monthly plans; yearly billing gives two months free |
| Free tier | 100 free verifications | 100 checks a month, 10 requests a minute, no credit card |
| Real-time API | Yes, timeout per request (default 6,000 ms) | Yes, GET /v1/info |
| Bulk | Batch API, up to 1 million addresses per request, optional callback URL; list upload in the app | Bulk API, up to 100,000 addresses per job, CSV/TXT upload, signed webhook |
| Result | result: deliverable, undeliverable, risky, unknown, plus reason | state plus reason, score 0–1 |
| Catch-all | accept_all flag on every check | Catch-all addresses come back deliverable with reason low_; catch_all field with catch_all=1 (Small plan and up) |
| Quality score | sendex, 0 to 1 | score, 0 to 1 |
| Other flags | role, free, disposable, did_you_mean | role, free, disposable, did_you_mean |
| Libraries | PHP, Node.js, Ruby, Python | JavaScript, Python, PHP SDKs, plus Ruby, Go, C#, R, Rust, Perl clients; MCP server |
The two APIs are close in shape: both return the address split into user and domain, the same three boolean flags and a typo suggestion. The differences sit in pricing, batch size and how catch-all domains are reported.
Where Kickbox is stronger
- A documented quality score. Kickbox’s
sendexscore (0 to 1, where 1 is best) is documented in every official library. Ourscoreworks the same way, but if you have tuned thresholds on Sendex, you will need to re-tune them. - A
riskyresult. Kickbox puts uncertain addresses into their ownriskyresult. We return catch-all addresses asdeliverablewith the reasonlow_deliverability, so you filter onreasoninstead ofstate. - Timeouts in the request. Each Kickbox library takes a
timeoutin milliseconds (default 6,000), useful on sign-up forms where a user is waiting. OurGET /v1/infotakes only the address and the optionalcatch_allflag. - Unknown results refunded. Kickbox refunds the credit when it can’t give a definitive result. We refund timeouts in bulk jobs when the job completes; single API calls that return a result count against your quota.
- Bigger batches. Kickbox’s batch API takes up to 1 million addresses in one request. Our bulk jobs take up to 100,000 each.
- Credits instead of a plan. A credit balance suits irregular volume. Our plans are monthly; for a one-off job you subscribe for a month and cancel.
Where emailvalidation.io is the better fit
Fixed monthly prices. Small covers 5,000 checks for $9.99 (0.20 cents each), Medium 25,000 for $34.99 (0.14 cents) and Large 100,000 for $94.99 (0.095 cents). The same volumes cost $40, $150 and $500 in Kickbox credits. Yearly billing gives two months free. The full table is on our email validation API pricing page.
Bulk jobs with webhooks. POST /v1/bulk takes up to 100,000 addresses as a JSON array or a CSV/TXT file of up to 25 MB. When the job completes, you get one signed webhook (HMAC-SHA256) and download JSON or a CSV with your original columns plus 15 result columns. Duplicates and invalid rows are free, timeouts are refunded when the job finishes, and a failed job is refunded in full. Large lists can take a day or longer, because checks are paced per receiving mail server. See email list cleaning service for the workflow.
Catch-all checks when you ask for them. Send catch_all=1 (Small plan and up) to get the catch_all field, for example on list cleaning but not on a sign-up form. Our guide to catch-all email covers what to do with those addresses.
Only successful calls count. Validation errors and server errors don’t use quota, and a 422 error names the field that caused it. The email validation API page shows the full request and response.
AI agents. A hosted MCP server lets Claude, Cursor and other agents check addresses and start bulk jobs.
What you give up compared with Kickbox: a separate risky result, the established Sendex score, a request timeout, refunded unknown results, batches above 100,000 addresses, and a credit balance instead of a monthly plan.
Moving from Kickbox
Kickbox result | emailvalidation.io state |
|---|---|
deliverable | deliverable (reason valid_mailbox) |
undeliverable | undeliverable (reasons such as invalid_mailbox, invalid_mx) |
risky with accept_all: true | deliverable, reason low_; catch_all: true with catch_all=1 |
unknown | unknown (reasons such as timeout, no_connect) |
Kickbox’s sendex becomes our score (also 0 to 1), and role, free, disposable and did_you_mean keep their names. Run the same 100 addresses through both services on the free plans and compare where they disagree before you switch.
Other Kickbox alternatives
Checked October 10–11, 2026, on each vendor’s own page:
- NeverBounce: $8 per 1,000 credits pay as you go, 100,000 for $400; Growth plan from $49 a month; credits expire after 12 months; 80+ integrations. See NeverBounce vs Kickbox and our NeverBounce alternative page.
- ZeroBounce: 5,000 credits for $69, 100,000 for $649; unknown results and duplicates are not charged; adds deliverability tools. Compare on our ZeroBounce alternative page.
- Bouncer: 5,000 credits for $35, 100,000 for $400; credits never expire; hosted in the EU. Details on Bouncer pricing.
- MillionVerifier: 10,000 credits for $39, 100,000 for $149, 1 million for $449; unknown and catch-all results are not charged; credits never expire. See MillionVerifier pricing.
Sources
Checked October 10, 2026: Kickbox Node.js library and Kickbox Python library (response fields, timeout, balance header, free account); Kickbox on GitHub (official libraries); ZeroBounce pricing FAQ; Bouncer pricing; emailvalidation.io pricing. Checked October 11, 2026: Kickbox pricing (price list, free verifications, unknown refunds, US and EU); Kickbox batch verification API (batch size, callback); NeverBounce pricing (pay-as-you-go volumes, Growth); MillionVerifier pricing slider.