Postcheck: Email Auth Monitor

Grade and fix SPF, DKIM, DMARC

Only for Mac

Free · In‑App Purchases

Mac

Find out why your mail lands in spam. Postcheck grades every domain A–F and gives you the exact DNS record that fixes each problem, then watches for changes. Postcheck watches your domains' email authentication from the menu bar and tells you, in plain English, what is wrong and the exact DNS record that fixes it. CHECKS • MX: records resolve, no dangling hosts, STARTTLS on port 25 • SPF: syntax, the 10-lookup limit, void lookups, +all/?all, includes followed all the way down • DKIM: keys found and decoded for your selectors and the common ones (Google, Microsoft 365, iCloud, Fastmail, Zoho, Mailchimp, Zendesk, Proton), key strength, CNAME'd selectors • DMARC: policy, pct, subdomain policy, report addresses and whether outside report addresses are authorised • MTA-STS, TLS-RPT and BIMI presence and validity • Blocklists: your mail server and SPF addresses on Spamhaus, SpamCop, Barracuda and SORBS GRADE AND FIX Every domain gets an A–F grade. Every finding comes with the host, type and value to publish. The SPF flattener rewrites over-limit records and reminds you when provider addresses drift. Provider wizards list the records Google Workspace, Microsoft 365, HubSpot, Mailchimp, SendGrid, QuickBooks and Zendesk need and compare them with live DNS. MONITOR Postcheck re-checks every six hours, shows the worst domain state in the menu bar, notifies you when a record changes or a grade drops, and keeps a timeline of every change. DMARC REPORTS Read aggregate reports from any IMAP mailbox (including Gmail with your own OAuth client), drop report files onto the window, or watch a folder. See who sends as your domain, pass rates, alignment and a daily trend, and get a straight answer to “is it safe to move to quarantine or reject?” with the unaligned legitimate senders listed. REPORT Export a PDF or Markdown report per domain, or one branded PDF covering all of a client's domains. FREE AND PRO Free: one domain, manual checks, the grade and every fix. Postcheck Pro (one-time purchase): unlimited domains, automatic re-checks, alerts, timeline, DMARC reports, blocklists and exports. PRIVACY DNS lookups use DNS-over-HTTPS. Mailbox passwords and tokens stay in your Keychain. Nothing is sent to the developer; there is no account and no analytics.

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Postcheck now belongs to Dakabi LLC. If you read DMARC reports from a mailbox, you'll be asked to reconnect it once after updating; macOS requires saved passwords and sign-ins to be re-entered after the move. Your domains and history are kept.

Version 1.1

The developer, Dakabi LLC, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .

  • Data Not Collected

    The developer does not collect any data from this app.

    Privacy practices may vary, for example, based on the features you use or your age. Learn More

    Accessibility

    The developer has not yet indicated which accessibility features this app supports. Learn More

    Information

    Seller
    Dakabi LLC
    Size
    1.9 MB
    Category
    Utilities
    Compatibility
    Requires macOS 14.0 or later.
    • Mac
      Requires macOS 14.0 or later.
    Languages
    English
    Age Rating
    4+
    In-App Purchases
    Yes
    Copyright
    © 2026 Josh Fisk
  • Developer Website
  • Privacy Policy