Frequently Asked Questions (FAQ)

Yes. While you are subscribed (including the free trial), incoming mail is analyzed automatically (mail you send and drafts are excluded). Analysis runs one message at a time, separately from what you do in Mail, so it does not hold up your normal use of Mail.

Apple Mail on macOS 15 or later. The app is available in Japanese and English. Brand impersonation checks cover brands in Japan as well as abroad (the UK, the US, Australia, Canada, Western Europe and more): postal services, tax authorities, banks, carriers, e-commerce, airlines and others.

LinkSentinel detects URLs in HTML and plain-text bodies (both the link destinations and URLs written in the text) and Bitcoin addresses. Because it never visits the links, it does not expand short URLs (if the short URL's domain differs from the sender, it is treated as a link of unclear relevance). The contents of images and attachments are not analyzed.

LinkSentinel combines several clues: the sender's address, checks that help verify where the message came from (SPF, DKIM and DMARC), matches against your saved domain lists, anything suspicious about the links (URLs written in the text that differ from the real destination, link destinations unrelated to the sender and so on), brand or own-domain impersonation, and whether you have received mail from the sender before. See the Criteria page for details.

• 🟢 Links Verified: a known sender, with nothing suspicious found
• ⚪️ Needs Review: nothing suspicious, but the sender is not in Trusted Senders (Whitelist) or Contacts and is writing for the first time (please check the part after @ in the sender's address, the sender domain)
• 🟠 Caution: something needs attention, such as brand impersonation, failed authentication or links of unclear relevance
• 🔴 Dangerous: dangerous signs such as a displayed URL that differs from the real destination (link text spoofing), a sender posing as your own domain, or a domain handled with care because it is often abused (Watch Domains / Untrusted Domains)
• ⛔️ Blacklisted: a known dangerous domain that matched Blocked Senders (Blacklist)

By default ("Watch only"), no verdict moves or flags mail; you are informed through the banner and the Email Analysis History. Notifications, moving to Junk and colors can be chosen under "Recommended Settings" in "Verdicts & Actions" in Settings (per-verdict settings are under "Advanced Settings").

LinkSentinel follows a policy of "never making doubtful mail look safe". Even when the checks that verify the claimed sender (sender authentication) pass and the links match the sender, a sender you hear from for the first time is marked "Needs Review" rather than green (Links Verified). Register senders you trust in Trusted Senders (Whitelist), in Per-Sender Links (Per-Sender Whitelist, ⌃⌥A) or in your macOS Contacts, and they show green from then on. Green does not mean the app vouches for a message; it means you registered your trust. The first page of the getting-started guide ("LinkSentinel judges cautiously") also explains this policy (open the guide any time from "Get Started with LinkSentinel…" in the menu).

Click the LinkSentinel icon in the menu bar. The top line shows the status, for example "Last analysis: 3 minutes ago (today 12; Dangerous 1)". If it reads "No response from the Mail extension yet", check that LinkSentinel is checked in Mail's "Settings…" → "Extensions". "Check Setup…" in the menu shows Subscription, Mail checking, Extension response and Last analysis together.

Choose "Get Started with LinkSentinel…" in the menu, or "Show the Getting Started Guide" in "Check Setup…". If you finish the guide without checking "Don't show this guide at launch for the next two weeks" on its last page, it appears again at the next launch.

You can try it free for 14 days. After that, choose one of these auto-renewing subscriptions:

• Yearly plan: $19.99 / year in the United States
• Monthly plan: $2.99 / month in the United States

Prices in other regions are shown in local currency in the App Store and in the app's subscription window. Payment is made through the App Store (your Apple ID). Prices may change; check the App Store and the subscription window for current prices.

When you first launch LinkSentinel, the "Get Started with LinkSentinel" guide opens. On its "Subscription" page, click "Open Subscription Screen", choose the Yearly or Monthly plan and click "Start Free Trial" (you can also open the subscription screen from "Subscribe…" in the menu bar icon). The trial lasts 14 days, and each Apple ID can use the free trial once. When 3 days or fewer remain, a notification lets you know. Unless you cancel at least 24 hours before the trial ends, the plan you chose starts automatically.

Cancel from "Manage Subscription…" in the LinkSentinel menu bar icon, or from Subscriptions in your App Store account settings. Subscriptions renew automatically unless cancelled at least 24 hours before the end of the current period. After you cancel, you can keep using LinkSentinel until the end of the period you have already paid for.

No. Phishing techniques change every day, so we keep updating LinkSentinel's decision logic and its default lists (frequently abused domains, brands' official domains, delivery service domains and more). To keep those updates coming, it is offered by subscription only.

Before you start the free trial, or after your subscription expires, the Mail extension does not analyze mail (banners, notifications, history recording, moving to Junk and everything else stop). In the menu bar, every item except "Subscribe…", "Get Started with LinkSentinel…", "How to Use" and "Quit" (Settings, Email Analysis History, shortcuts and so on) becomes unavailable. You are notified when your subscription ends. Your settings, the lists you registered and the analysis history stay on your Mac and are available again when you resubscribe. Mail that arrived while you were not subscribed is not analyzed automatically afterwards (it is analyzed when, for example, you open it in Mail).

Yes. Family Sharing is supported, so members of your Family Sharing group can use the same subscription at no extra cost. You can change sharing in your Apple ID's subscription settings.

Yes. Any Mac signed in with the same Apple ID can use it at no extra cost. If your subscription does not show up, click "Restore Purchases" in the subscription window.

Payments are processed by Apple, so refunds follow Apple's policy. Request a refund through Apple's "Report a Problem" (reportaproblem.apple.com). The developer cannot process refunds.

Yes. Choose the other plan in the subscription window and click "Switch to This Plan", or change it in your App Store account settings. Yearly and Monthly are the same tier, so a change takes effect on your next renewal date, after the current period ends. The remaining period is not refunded, and the free trial is available only once.

Not for analyzing mail. All analysis happens on your Mac; LinkSentinel never visits the links and never sends message content to an external server. Verdicts are the same offline. Only starting the subscription (including the free trial) and checking renewals involve communication with the App Store.

Checks have minimal impact on how fast messages load, and you can keep reading and using Mail while they run in the background.

The impact is minimal. Messages are analyzed one at a time when they arrive (or, if not yet analyzed, when you open them), and analysis involves no network access. Even mail with large attachments is analyzed quickly, because the contents of attachments are not analyzed.

Yes. All analysis runs on your Mac. Message content and link information are never sent to an external server (LinkSentinel contacts the App Store only to check your subscription). See the Privacy Policy for details.

No, the content of your mail is never sent anywhere. All processing stays on your Mac; it is designed with privacy as the top priority.

LinkSentinel is a tool that gives you more information to decide with. It cannot stop 100% of threats. Whether to act on a suspicious link is ultimately your decision.

Select the message in Mail and press ⌃⌥A ("Allow Links from This Sender…", which registers it in Per-Sender Links) or ⌃⌥S ("Trust This Sender…", which adds the sender's domain to Trusted Senders); from then on it is less likely to be flagged. You can also select the row in the Email Analysis History and use the buttons in the detail pane. If you correspond with people in China, Russia or similar countries, set that country to "Normal" under "Country and Region Top-Level Domains" in Advanced Settings of the "General" tab (this setting covers domain endings such as .cn and .ru). See Settings for details.

Yes. Mail whose sender or link destinations include a domain in Blocked Senders (Blacklist) is classified as "Blacklisted", ahead of every other setting. To move it to Junk, choose "Move dangerous mail to Junk" under "Recommended Settings" in "Verdicts & Actions" (mail is not moved by default). Select a message in Mail and press ⌃⌥X ("Block This Sender…") to add its sender domain. You can also block whole countries or regions at once (Advanced Settings in "General").

By default, LinkSentinel does not move mail to the Junk folder. If you choose moving to Junk in "Verdicts & Actions" (a confirmation dialog appears when you do), legitimate mail can be moved by mistake and disappear from your inbox. If moving is on, check your Junk folder regularly. Moved messages are also listed in the Email Analysis History (⌃⌥D), and registering the sender in Per-Sender Links (⌃⌥A) makes it less likely to be moved next time.

Yes. "Enable Notifications" in "General" turns all notifications off, and in "Verdicts & Actions" you choose which verdicts notify you (the default, "Watch only", sends none).

By default, Russian (.ru and others) and Chinese (.cn and others) domains are treated as "Dangerous". If you correspond with business partners or family there, set that country to "Normal" under "General" → "Advanced Settings" → "Country and Region Top-Level Domains" in Settings. If Simplified Chinese or Russian is among your Mac's preferred languages, it is already "Normal" from the start.

They let you allow specific link destinations only when they appear in mail from a particular sender. This keeps legitimate mail from being flagged again and again when the sender is genuine but the links go to another domain, such as a mail delivery service. Select a message in Mail and press ⌃⌥A ("Allow Links from This Sender…") to register it.