Kickbox API

Beginner's Pick Email / No Auth Required Beginner HTTPS CORS
Free to Use
71 B
Measured Score 0 50 100 Speed 19/30 Consistency 20/20 Security 18/20 Browser access 10/15 Transparency 4/15 TESTED 2026-08-10

Overview

Kickbox provides a free, no-auth email verification endpoint that checks whether an email address is deliverable by performing syntax validation, domain MX lookup, and disposable address detection. The open endpoint at open.kickbox.com requires no API key and returns a quick binary verdict, while paid plans offer deeper SMTP verification. It is commonly used in form validation to catch bad emails at point of entry.

Beginner Tip

Kickbox open endpoint needs no API key — just append an email address to the URL and you get an immediate JSON response. It is one of the easiest ways to add basic email validation to a signup form without any registration.

Measurement Record

What actually happened when we called this API from our own infrastructure. Every value below was recorded by the request, not copied from the provider's documentation.

Request
GET https://open.kickbox.com/v1/disposable/[email protected]
Result
HTTP 200 · application/json · 19 bytes
Response time
201 ms (median of 3) · fastest 199 ms
Transport
TLSv1.3 · TLS_AES_128_GCM_SHA256 · certificate issued by Amazon
Browser CORS
Allowed — Access-Control-Allow-Origin: https://apisscore.com
Recorded
2026-08-10

Fields Returned

Top-level fields present in the response we captured, with the type and value we actually received.

Field Type Value received
disposable boolean true

Captured Response

Captured from a real request to https://open.kickbox.com/v1/disposable/[email protected] on 2026-08-10. Long arrays and nested objects are truncated to keep the shape readable.

JSON Response · Captured
{
  "disposable": true
}

Field Reference

disposable True if the email domain is a known temporary or disposable email provider

Implementation Example

Calls a real endpoint of this API. Replace any placeholder credentials with your own key.

Request
const url = "https://open.kickbox.com/v1/disposable/[email protected]";
const response = await fetch(url);
if (!response.ok) throw new Error(`Request failed: ${response.status}`);
const data = await response.json();
console.log(data);

What Can You Build?

Note: These code examples are AI-generated and unverified. Always refer to the official API documentation for accurate usage.

Common Errors & Troubleshooting

Generated guidance based on this API's documentation, not observed by us. Treat it as a starting point and check against the provider's own error reference.

Response shows "disposable": true for a real business email Some corporate email domains use infrastructure shared with disposable providers, triggering false positives
Use disposable as one signal alongside result — only reject if both result is undeliverable AND disposable is true
CORS error when calling from browser JavaScript The open.kickbox.com endpoint may not send CORS headers for all origins
Call the API from your server-side code and return the result to the front end, rather than making the request directly from the browser
No response or timeout for certain domains SMTP probing can time out for domains with strict firewall rules on port 25
Set a 10-second timeout and treat timeouts as unknown rather than invalid; do not block users solely on a timeout result

Measured Score Breakdown

Live HTTP request to the API endpoint

Speed 19/30
Consistency 20/20
Security 18/20
Browser access 10/15
Transparency 4/15
Endpoint Response Time 201ms

Fully tested on Aug 10, 2026

Technical Specifications

Auth No Auth
HTTPS REQUIRED
CORS YES
Category Email
Difficulty Beginner
Endpoint last called: 2026-08-10

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