Kickbox vs MailboxValidator

Kickbox has no write-up on Specifiction yet; its figures are above.

MailboxValidator checks email addresses and mailboxes to flag invalid addresses and help reduce email bounces. It is available on the web and through an API, with single-address results returned as JSON or XML. For lists, users can upload text or CSV files for bulk validation. Checks cover syntax, MX records, SMTP responses, greylisting, disposable and free-provider addresses, role addresses, suppression, DMARC, strict SPF, and website reachability. The company says it tests the connection through the SMTP server without sending a message to the recipient. Listed integrations include Zapier, Make, MailChimp, Mailgun, SendGrid, HubSpot, and others; API documentation links libraries for Node.js, Ruby, PHP, Perl, Python, Java,.NET, Go, and Rust. The free API plan is free, billed per month, with 300 queries and 30-day validity. A bulk trial is free for 100 queries and 30-day validity. Yahoo validations are unsupported, and non-ASCII addresses are marked invalid syntax. The FAQ says refunds are not offered; its privacy policy says processed personal data is retained indefinitely, subject to policy limits on deletion requests.