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MailboxValidator review

Freemium#32 of 36 in Email Verification ServicesEmail Verification APIs

A practical verifier for bulk list hygiene, signup forms, and developer workflows.

5.5/10Editor score
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MailboxValidator5.5 Try MailboxValidator

Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026

MailboxValidator is an email verification service for marketers, developers, and organizations that need to check individual addresses or clean subscriber lists. The web portal supports single-email checks and TXT or CSV uploads, while the REST API fits signup forms, CRMs, point-of-sale systems, and other data-entry workflows. Its checks cover syntax, DNS and MX records, MX server connections, SMTP connectivity, disposable addresses, role accounts, free-email providers, suppressed addresses, and duplicates. Results are available through the interface or in JSON and XML formats.

Its standout strength is the range of validation signals in one workflow. MailboxValidator combines list cleaning with real-time SMTP-based validation, making it relevant for both existing subscriber databases and new addresses collected through forms. Integrations include Mailchimp, SendGrid, AWeber, Mailgun, and ActiveCampaign. That ecosystem fit gives marketing teams several ways to incorporate verification alongside their email operations, while developers can work directly through the API.

The published plan structure separates bulk and API usage. BULK-TRIAL provides 100 queries with 30-day validity and standard support; BULK-1 provides 1,000 queries with 30-day validity and email support. API-FREE provides 300 monthly queries with auto renewal, auto recharge, and standard support, while API-3 and API-15 provide 3,000 and 15,000 queries respectively, each with 30-day validity, auto renewal, auto recharge, and email support. Credits do not roll over, so it suits teams able to use their allocation within each cycle. Choose MailboxValidator for standard checks, bulk uploads, and API access; consider an alternative if permanent free access or unused-credit carryover is important.

MailboxValidator pros and cons

  • Where it wins
    • Checks syntax, MX records, SMTP connectivity, and disposable addresses
    • Supports TXT or CSV bulk uploads and real-time SMTP validation
    • REST API returns results in JSON or XML and connects with major email tools
  • Where it doesn't
    • Credits and validation results operate on 30-day validity periods
    • No credit rollover for unused bulk or API queries
    • Paid plans require choosing separate bulk or API query packages

MailboxValidator fact sheet, pricing and score →

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