Gmailtail: Command-Line Gmail Monitoring Tool

Gmailtail is a command-line tool for real-time monitoring of Gmail messages, outputting them as JSON. It offers flexible filtering (sender, subject, labels, attachments, etc.), multiple output formats (JSON, JSON Lines, compact), OAuth2 and service account authentication, and checkpointing. Users can customize monitoring rules via simple command-line arguments or a YAML configuration file, making it ideal for automation, monitoring, and integration with other tools.