I need a small, reliable solution that will look at a Google Sheet or an Excel file, pull the case filing date I keep there, and fire off reminder emails from my own domain through Thunderbird. The data connection has to be hands-off: once the sheet is updated the tool should pick up the case data and filing date, calculate the next renewal deadline, and queue the message. To keep everything on-track I work with fixed renewal cycles, for example: • EU Trade Mark – every 10 years • EU Design – every 5 years • US Trade Mark – after 5 years, 10 years, then each 10 years • Philippines – 3, 6, 10 years, then each 10 years Given the case code and basic client details, the system must select the right template, merge the data, and send the email so it appears exactly as if I sent it myself from Thunderbird. A simple log or dashboard that confirms what went out and what is coming up would be ideal. I am potentially open to change e-mail client but must be guided with messages migration, I cannot lose any. I’m aiming to have this running within a month, so please outline how you would: 1. Connect to the sheet automatically. 2. Integrate with Thunderbird or otherwise send through my domain without exposing credentials. 3. Handle the rule-based scheduling and template merging. 4. Provide straightforward installation or deployment steps on Windows. Clean, maintainable code and clear documentation are a must. Let me know if you have built something similar or can show a quick proof-of-concept.