Wud is a self-hosted container image update monitoring system that periodically checks running containers against their registries and reports when newer image versions are available. It detects updates by comparing SHA-256 digest hashes of container image manifests rather than relying on version tags, and persists last-known image digests and notification states to avoid duplicate alerts across restarts.
The system abstracts different container registry APIs behind a unified interface, supporting Docker Hub, GHCR, Quay, and others, and runs update checks on a configurable cron-like schedule with per-container polling intervals. When new image versions are detected, it sends notifications via configurable webhook endpoints to services like Slack, Discord, or email. All functionality is packaged into a single executable binary with no external runtime dependencies, keeping all data local without relying on external services.
