I built (and still am building 
) a web app (currently intended for self-hosting) that watches Nixpkgs packages that you track and sends you notifications whenever it detects a new version.
How it works: You set up tracking for packages you care about and configure your notification channels (webhooks and email). Package versions are checked automatically on configurable schedule, or you can trigger it manually via UI.
Why use it? Package updates merged into nixpkgs can take anywhere from a few days to over a week to reach your machine, depending on your channel and how busy Hydra is. nixpkgs-notifier notifies you as soon as it detects a new version so you can decide whether to act immediately (e.g. pin your flake input to that commit) rather than waiting for the channel to catch up - which can come in handy for security updates. It’s also useful for rarely updated packages (e.g. legacy software) where you don’t want automatic updates but still want to know when something changes so you can decide if it’s worth applying.
Comes with NixOS module for easy deployment.
Would love any feedback!