Where do filtered emails go in Plain?

Before a thread is created, Plain scans every inbound email for two automated-message signals: forwarded auto-replies and emails sent from Plain's own notification addresses (to prevent notification loops). An email matching either signal is filtered: it does not create a thread.

What gets filtered

Plain identifies auto-replies using a combination of standard headers (such as Auto-Submitted, Precedence: auto_reply, and provider-specific headers like Salesforce's X-SFDC-AutoResponse or Exchange's generated-message header) and subject line patterns (e.g. "Automatic reply:", "Out of office:") across 20+ languages. A subject pattern alone is not enough to filter an email; Plain requires at least one supporting header signal alongside it, to reduce false positives.

What happens to a filtered email

A filtered email does not create a thread, does not trigger any workflows, and does not generate any notifications. There is currently no settings page where filtered emails can be viewed or recovered.

If a specific automated sender is slipping through and creating threads instead of being filtered, because it does not send standard auto-reply headers, set up a workflow with trigger Thread created, a Message contains condition for phrases like "your request has been received," and action Mark as Done, to keep it out of your queue.