Cup

Cup is a lightweight service and CLI that checks your container images for available updates across common registries. It focuses on high performance, low resource usage, and providing clean JSON output for integrations.

Key Features

• Fast update checks optimized for CPU efficiency
• Works with multiple registries (including Docker Hub, GHCR, Quay, LSCR, and Gitea-compatible registries)
• Web interface plus a terminal-friendly CLI
• JSON output for scripting, dashboards, and external integrations
• Designed to minimize or avoid exhausting registry rate limits
• Support for running multiple Cup servers and viewing them from a single web interface

Use Cases

• Homelab or server operators checking for outdated container images
• Scheduled update reporting via cron jobs and JSON output parsing
• Centralized visibility into image update status across multiple hosts

Limitations and Considerations

• Does not directly trigger integrations or automations; you must poll results (for example via the CLI or the server JSON API)

Cup is well-suited for users who want a small, fast, self-contained way to monitor container image updates without running a heavier automation platform. Its CLI, web UI, and JSON output make it easy to fit into existing workflows.