Pin your Python project's dependencies so a teammate can rebuild it

It works on your machine. It breaks on theirs.

BeginnerRead 5 minDoing: twenty minutes6 steps

▶ Start

What you'll have at the end

A requirements.txt file that installs the exact same package versions on any machine

Before you start

You need

A Python script of your own that already runs and imports at least one package you installed yourself, not something from the language's standard library alone.

Not covered

This does not cover locking exact cryptographic hashes for extra supply-chain protection, or producing one file that resolves identically on every operating system; it only covers matching exact package versions between two machines on the same operating system.

Leans on

Set up a clean, project-only environment

Give the project its own environment
Install exactly what the script imports

Turn what's installed into one shareable file

Record every version now installed
Keep the pin file with the code

Rebuild it elsewhere and keep it honest

Rebuild the exact environment elsewhere
Regenerate the file, never hand-edit it

Checked 25 Aug 2026

Part of the Python cookbook