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What HeaderCheck does

HeaderCheck shows plain-language SPF, DKIM, and DMARC verdicts from pasted headers or an .eml file. Analysis runs on your iPhone or iPad. There is no account and no upload to a developer server.

How to get headers on iPhone

Apple Mail does not show raw headers in a convenient copy field. A reliable path is to forward the message as an attachment (or use Share / Open In) and open the .eml in HeaderCheck (opening files requires Pro). In Gmail or iCloud on the web, use Show original / view message source, then paste into the App; pasting is free. The in-app Learn tab walks through these steps.

Reputation hints

With HeaderCheck Pro, results include warn-only reputation hints: whether the From domain is on a bundled disposable-email or freemail list, and which public relay IPs appear in the Received headers. These checks run on your device. Hints are context, not a verdict about a message, and they are included in Copy Summary and PDF export.

Optional live DNS lookups (also Pro) are off by default. If you turn them on in Settings, HeaderCheck uses your device’s DNS resolver to check relay IPv4 addresses against the SpamCop (bl.spamcop.net) and PSBL (psbl.surriel.com) block lists and to look up the From domain’s SPF, DMARC, and MX records. Headers are never uploaded. If a lookup times out, the result is shown as unknown. Networks that block or rewrite DNS may make these hints incomplete.

Free and Pro

The free tier covers header analysis: paste headers and get the core SPF, DKIM, and DMARC verdicts. HeaderCheck Pro is a one-time purchase that unlocks reputation hints (including optional live DNS lookups), PDF export, analysis history beyond the free cap, and opening files of any type through Share, Open In, or the in-app file picker. Purchases are handled by Apple.

Contact

Email [email protected] with the device model, iOS version, and a short description of the issue. Do not send full email headers or message contents unless you intentionally want help reviewing a specific sample.

Privacy

See the HeaderCheck Privacy Policy for how data is handled.

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