Comparison
Verimail vs Kickbox
Two email verification APIs for the form, side by side: what one call returns, what it costs, and how each handles an address the mail server will not confirm.
Every Kickbox fact on this page was read from Kickbox's own pages:
Kickbox is an email verification service from J2 Martech Corp, a Ziff Davis company, with a single-verification API, a batch API, list verification, deliverability consulting and native integrations with marketing platforms. Verimail is an email verification API and file verifier from Verimail Ltd, built around one rule: a result is a conclusive verdict with its reason, or an honest unknown that costs nothing.
Both check an address's syntax, its domain and its mailbox with the receiving mail server, and both answer with one of four results: deliverable, undeliverable, risky or unknown. This page is for a developer choosing an API to validate addresses as they are typed into a signup, checkout or lead form. Every fact about Kickbox comes from the pages linked above; check them before you decide.
What one call returns
| Verimail | Kickbox | |
|---|---|---|
| Request | POST or GET https://api.verimail.io/v3/verify with a Bearer key; one call, one answer | GET https://api.kickbox.com/v2/verify?email=…&apikey=…; EU-only accounts call api.eu.kickbox.com |
| Result buckets | verdict: deliverable, undeliverable, risky, unknown | result: deliverable, undeliverable, risky, unknown |
| Reason with every result | Yes: reason, a named reason, each defined on the result codes page | Yes: reason, one of 11 values, e.g. accepted_email, rejected_email, low_deliverability, no_connect, timeout |
| Score | None. A verdict and its reason; nothing to threshold | Sendex, a quality score from 0 to 1 |
| Suggested action | suggested_action on every answer: accept, accept_and_confirm or reject | Not a field. The docs describe tagging, flagging or rejecting on result |
| Flags | flags: disposable, role_account, free_provider, catch_all | role, free, disposable, accept_all |
| Typo suggestion | did_you_mean | did_you_mean |
| Catch-all domains | risky, reason domain_catch_all. A random address and yours are both tested, so a full or dead mailbox on a catch-all domain still gets its own verdict. Billed | accept_all: true; accept-all, disposable and role addresses are classified as risky |
| The mail server's reply | On request (evidence=true): the SMTP exchange step by step, the MX host, TLS and timings | Not returned |
| Timeout | timeout in milliseconds, 1,000 to 45,000, default 45,000. On expiry: verdict unknown, reason timeout, not billed | timeout in milliseconds, default 6,000, maximum 30,000. On expiry: result unknown, reason timeout |
| When the server won't answer | verdict unknown with the server's reason (greylisted, timeout, no_greeting, relay_blocked…). Not billed, and the response says so | result unknown when no response could be obtained from the recipient's mail server; the docs suggest retrying after about 5 minutes. Unknowns do not count against the balance |
| Billing in the response | billed: true or false on every answer | Not a field |
Pricing
One-off packs in US dollars, from each pricing page. Kickbox's API product page shows higher figures for some packs than its pricing page; the pricing page is used here.
| Verimail | Kickbox | |
|---|---|---|
| Model | Pay-as-you-go packs and monthly plans; one credit pool for the API and files | Pay-as-you-go packs; volume discounts on request; auto-recharge |
| Free tier | 100 verifications a month, no card, renewing monthly | 100 verifications |
| Smallest purchase | 1,000 credits, $4 | 500 credits, $5 |
| 1,000 credits | $4 | $10 |
| 10,000 credits | $20 ($2 per 1,000) | $70 ($7 per 1,000) |
| 100,000 credits | $100 ($1 per 1,000) | $500 ($5 per 1,000) |
| 1,000,000 credits | $500 ($0.50 per 1,000), or $299 a month on the Enterprise plan ($0.30 per 1,000) | $2,999 ($3 per 1,000) |
| Monthly plans | Starter $15 (10,000 a month), Professional $79 (100,000), Enterprise $299 (1,000,000) | None listed on the pricing page |
| Credits expire | Never | to verify Not stated on the pricing page |
| Unknown results | Not billed. Neither are syntax errors, and in files duplicates | Not billed: "if we can't provide a definitive result to you, we'll refund the credit" |
Fit for a signup, checkout or lead form
| Verimail | Kickbox | |
|---|---|---|
| Real-time single check | Yes: one HTTP call, the verdict in the response | Yes: one HTTP call |
| Lists | File upload in the dashboard, any size, same rules; no batch endpoint on the public API | List upload in the app, and a Batch Verification API (up to 1 million addresses per job, per the product page) |
| Client libraries | None. Plain HTTP; snippets in curl, Node, Python, PHP and Go in the docs | Official Node.js, PHP, Python and Ruby; community Java, Go and .NET |
| Test mode | None. The free key's 100 a month serve for testing | Sandbox mode with a separate sandbox key |
| Integrations | None | 28 listed, including HubSpot, Mailchimp, Salesforce and Zapier |
| Data handling | Addresses sent to the API are kept only in a 30-day request log; uploaded files and results are deleted 30 days after upload. Verimail Ltd, UK; DPA on request | GDPR and SOC 2 stated on the pricing page; EU-only accounts available. Retention period: to verify |
Where the two are the same
- The same four result buckets, each with a named reason.
- Disposable, role and free-provider flags, and a suggested correction for typos.
- A per-request timeout in milliseconds, and an unknown when it runs out.
- Neither charges for an unknown result.
Where Kickbox has more
- Official client libraries, a sandbox mode, a batch API and native integrations with marketing platforms.
- A quality score (Sendex) if you want one number to threshold on.
- SOC 2 certification stated, and an EU-only account option.
Where Verimail differs
- The mail server's own reply on request, so a rejected user can be explained from the response.
- A
billedfield and a suggested action in every answer. - A longer timeout ceiling (45 s against 30 s) for the flows that can wait.
- A free tier that renews monthly, monthly plans, and a lower price per thousand at every pack size in the table.
Prices and features change; Kickbox's pages linked above are the source of truth. If something here is out of date, tell us and we will fix it. Other comparisons: Verimail vs Emailable,Verimail vs Verifalia.