Kickbox

What is Kickbox?

Email verification API built for deliverability-focused marketers. Verifies email addresses at point-of-capture to prevent fake, mistyped, and disposable emails from entering databases. Trusted by over 100,000 businesses.

Key features

Single & Bulk Verification

Verify individual addresses via API or upload lists up to 1 million emails via dashboard or batch API

Sendex Score

Proprietary 0-1 deliverability score that predicts inbox placement quality beyond binary valid/invalid

Real-time API

Verify emails at point of capture in account creation, mobile apps, newsletter signup, and reservation forms with instant responses

Typo Detection

Detects common email typos and returns 'did you mean' suggestions

Disposable Detection

Identifies disposable, role-based, and free email provider addresses

Inbox Placement Testing

Test email deliverability beyond verification

Email Threat Score

Separate product for additional deliverability intelligence

Batch Processing

Process up to 1 million emails in a single request with fast results

Kickbox pricing

Pay-as-you-go pricing with no monthly commitment. Free 100 verifications on signup. Volume discounts available. Unknown result credits returned to balance.

Plan	Price	What's included
Free	$0	100 verifications
Basic	$5	500 verifications
Standard	$10	1,000 verifications
Growth	$25	2,500 verifications
Professional	$40	5,000 verifications
Business	$80	10,000 verifications
Enterprise Tier 1	$200	25,000 verifications
Enterprise Tier 2	$400	50,000 verifications
Enterprise Tier 3	$800	100,000 verifications
Enterprise Tier 4	$1,500	250,000 verifications
Enterprise Tier 5	$2,500	500,000 verifications
Enterprise Tier 6	$4,000	1,000,000 verifications

Pros & cons

Pros

+ No monthly commitment—pure pay-as-you-go flexibility
+ High accuracy with 95% guaranteed
+ Transparent, cost-effective pricing scaled to usage
+ Sendex score provides nuanced deliverability rating beyond binary pass/fail
+ Developer-friendly with clean API and SDKs in Node.js, PHP, Python, and more
+ Fast real-time processing at point of capture
+ Supports verification of up to 1 million emails in batch
+ Credits returned for unknown results, allowing retry without additional cost
+ Wide integration ecosystem with ESPs including HubSpot, Mailchimp, Customer.io
+ Inbox placement testing included
+ Optional auto-recharge feature prevents API downtime
+ Discounts available for nonprofits, startups, and ESP partners

Cons

− No native sync with email platforms (unlike NeverBounce Sync)
− Smaller ecosystem of direct integrations compared to some competitors
− Deliverability consulting is an add-on cost

Who is Kickbox best for?

• Developers building email capture workflows and signup forms
• Small teams and startups starting with minimal cost via pay-as-you-go
• Marketing teams prioritizing data quality and nuanced deliverability scores
• SaaS platforms and mobile apps verifying emails at point of entry
• Teams syncing lists from HubSpot, Mailchimp, or other marketing platforms
• Companies focused on maintaining sender reputation and reducing bounce rates

Frequently asked questions

Is there a monthly commitment?

No. Kickbox offers pay-as-you-go pricing with no monthly subscription or annual contract required.

How are verification credits calculated?

Based on usage. Credits purchased are not bound to specific email lists and can be used across all Kickbox products (API, list verification, ESP integrations).

What are email verification credits?

Digital currency used to verify email addresses. One credit verifies one email address.

What does the Sendex Score measure?

A proprietary 0-1 deliverability score that predicts inbox placement quality and email engagement likelihood beyond a simple valid/invalid result.

What are the API limits?

25 parallel requests per IP and 8,000 requests per minute.

What results can the API return?

Deliverable, undeliverable, risky, and unknown. Unknown results return credits to your balance.