Azure Event Grid

Event Grid is how I stopped polling. Instead of asking Microsoft 365 every few minutes whether anything happened, the events arrive, and the code that handles them gets to be a small function with one job.

This topic covers the whole chain: what Event Grid is and why a partner topic beats a webhook subscription for Graph mail events, where events go when delivery fails, how to get an alert about those dead letters when the portal will not offer you one, and the Easy Auth setting that silently rejects deliveries until you exclude the right path.

It is a small topic, and it reflects a recent change in how I build these integrations. I am not going back to polling.