MailSide

When switching modes, MailSide ensures a seamless transition: going Native → App Control automatically copies all your existing native Gmail filters to its virtual store and removes the originals to prevent parallel execution. Switching back writes all filters back to Gmail in native format. Nothing is lost.

App Control mode uses the Gmail History API: the engine queries only emails received since the last run at each trigger, then matches filters in priority order. Typical latency with a per-minute trigger is 30–60 seconds; with sub-minute emulation as low as 1 second is achievable.

When saving a filter, the "Apply to existing emails" option can be enabled: the engine immediately runs the new rule on the current inbox contents, processing up to 500 emails in one run. No need to manually sort inboxes that have accumulated for years – write the rules once and MailSide does the work in minutes.

The sender blocking feature is particularly powerful: the `blockSender` action assigned to a filter adds the sender to the blocked list and automatically moves the email to Spam. The Sender History service tracks how many emails you've received from each sender – and can be used as special conditions in filters: `senderIsNew` (no previous email from this sender), `senderMinCount` and `senderMaxCount` (based on email count boundaries).

With the automatic attachment saving feature, when a filter matches, MailSide automatically saves attachments to Google Drive. A "MailSide Attachments" folder is created in the Drive root (if it doesn't exist), and files are saved with a date-prefixed name. Ideal for automatically archiving invoices, contracts, important documents – without human intervention.

Stale Filter Detection shows a status badge on every filter card: 🟢 if there was a match within the last N days, 🔴 if no email has matched for N days, ⛔ if the filter has never matched. This immediately shows which filters have become "dead weight" – you can delete or rewrite them. The inactivity threshold is configurable in settings, defaulting to 30 days.

Gmail "Important" AI override protection solves a particularly annoying Gmail behavior: Gmail's own AI sometimes removes the "Important" flag from emails that your filter would have explicitly marked as important. If the engine applied an `addLabel: IMPORTANT` action but the Gmail AI then removes it – MailSide re-reads the message and puts the flag back. Completely automatically.

The three-layer SPAM protection ensures no filter can accidentally remove emails from the Spam folder: (1) Per-filter spam-guard: only allows spam operations if the filter explicitly has `removeLabelIds: SPAM`. (2) Sender-block override: emails from blocked senders are never unspammed. (3) Global SPAM protection toggle: when enabled, no filter can remove the SPAM label – this is the default state.

In the Audit Trail view, you see in a stats grid the time of the last run, number of processed emails, number of matches, and any errors. In the log list, every entry shows the sender, subject, run mode (priority/native/external-change) and a summary (how many of how many filters matched). The expandable detail row shows per filter what matched, what didn't, and what actions the engine performed.

The log also displays special flags: snoozeReturn (snoozed email returning), scheduledSend (scheduled send), noreply (no-reply sender), replyToMismatch (Reply-To and From mismatch). These are details Gmail's interface doesn't show at all, but can be useful for fine-tuning rules.

XML export/import works in Gmail-compatible format: the exported file can be imported directly into Gmail settings too, and is portable to another Google account. This ensures the rules you write in MailSide are never locked into a single platform. Keyboard shortcuts (Ctrl+N new filter, Ctrl+F search focus, Ctrl+A select visible, Delete delete selected, Esc close modal) enable fast work.