What is youtube-websub-monitor?

youtube-websub-monitor is a service that watches YouTube channels for new videos and pushes out notifications with extremely low delay, instead of the usual approach of repeatedly polling YouTube for changes. It uses Google's own WebSub protocol, formerly known as PubSubHubbub, so that Google's servers notify the service directly the moment a new video is published, rather than the service having to check in on a schedule. The project is built with FastAPI in Python. When Google's hub sends a notification, the service immediately replies with an empty 204 response and hands the actual parsing work off to an asynchronous queue in the background, so that a burst of simultaneous notifications from Google does not slow down or block the service. It also includes a filter designed to prevent a known WebSub problem: when a YouTube creator edits an old video's title or description, YouTube sometimes resends that old video through WebSub as if it were new, and this filter catches and ignores those false alerts. Subscriptions to Google's WebSub hub expire after a default period of five days, so the service runs a background process that automatically renews each subscription before it lapses. New video information is stored using a lightweight SQLite database with automatic cleanup of records older than seven days, so storage does not grow without bound. When a new video is detected, the service also calls the YouTube Data API to fetch extra details like the high resolution thumbnail and the channel's avatar image, then can forward that structured information either to a webhook you set up yourself or directly to a Telegram bot and chat. Channels to monitor can be added or listed while the service is running through a small built in API, protected by a bearer token you set in the configuration. Setup requires Python 3.10 or later, a YouTube Data API key, and a public domain or IP address that Google's hub can send notifications to. The project is released under the MIT license.