nix-versions is a CLI tool that can help you find the nixpkgs revision for historical versions of a package.

It does so by integrating the following services available to the nix ecosystem:

• https://search.nixos.org (via the nix-search-cli elastic-search client). Used to search packages by program name or attribute name wildcards.

• https://nixhub.io - as default backend for package version resolution.

• https://lazamar.co.uk/nix-versions/ - search package versions by nixpkgs channel.

• https://history.nix-packages.con - another community provided versions index.

Any of these backends can be selected as default or combined on a per-package basis.

It also features version constraint filters, allowing you to restrict packages to a known set of compatible/stable versions that work with you.

When used in conjuction with nix shell and direnv, nix-versions, it can also double as a plain-text development shell and tools version manager with automatic environment loading targeting people new to nix, but familiar with tools like npm, rvm, asdf, mise.

Our website provides a flakes generator for version-pinned packages. You can use these generated flakes as inputs on your own flakes, allowing version constrained package updates.

Read more at our website