What is pip in Python?

pip is Python's standard package installer, maintained by the Python Packaging Authority (PyPA). It installs and manages packages from the Python Package Index (PyPI) and other indexes, and ships with modern Python installations.

What is the difference between pip and pip3?

pip and pip3 are the same installer, just tied to different Python interpreters. On systems with both Python 2 and Python 3 installed, pip3 explicitly targets Python 3; on modern Python 3-only systems they are usually identical. The safest invocation is `python -m pip`, which always uses the interpreter you ran it with.

How do you install a package with pip?

Run `pip install ` to install the latest version, `pip install == ` to pin a specific version, or `pip install -r requirements.txt` to install everything listed in a requirements file. Use `pip install -e .` to install the current project in editable mode.

Is pip better than uv?

pip is the default installer that ships with Python, but uv resolves and installs packages 10-100x faster and also manages Python versions, virtual environments, and reproducible lockfiles. For most new projects uv is the stronger default; pip remains the right choice when you want the tool built into Python itself or when a workflow depends on pip-specific behavior.

Does pip support lockfiles?

pip 25.1 added experimental support for generating PEP 751 `pylock.toml` lockfiles via `pip lock`, and pip 25.1 also added installation of PEP 735 dependency groups. Lockfile support does not yet cover environment markers or multi-platform resolution, so tools like uv or Poetry remain stronger choices for production lockfiles today.

pip: Python Package Installer

by Tim Hopper

Packaging

pip is the Python Package Authority’s (PyPA) standard package installer. It enables installing and managing Python packages from the Python Package Index (PyPI) and other package indexes. pip comes with modern Python installations and serves as the default tool for package operations in the Python ecosystem.

While pip remains Python’s default package installer, many workflows benefit from newer tools like uv that provide better performance and more integrated functionality.

Core Functionality

pip provides essential package management capabilities:

Installing packages from PyPI and other indexes
Uninstalling packages from environments
Managing requirements files
Installing packages in editable mode for development
Generating PEP 751 pylock.toml lockfiles (experimental, added in pip 25.1)
Installing PEP 735 dependency groups (added in pip 25.1)
Installing dependencies declared with PEP 723 inline script metadata (added in pip 26.0)

Key Commands

Installing Packages

# Install latest version
pip install requests

# Install specific version
pip install requests==2.31.0

# Install from requirements file
pip install -r requirements.txt

# Install a PEP 735 dependency group from pyproject.toml
pip install --group dev

# Install dependencies declared in a PEP 723 script
pip install --requirements-from-script script.py

# Install current directory in editable mode
pip install -e .

Managing Requirements

# Output installed packages
pip freeze > requirements.txt

# Install from requirements
pip install -r requirements.txt

# Generate a PEP 751 lockfile (experimental)
pip lock -r requirements.txt -o pylock.toml

Package Information

# List installed packages
pip list

# Show package details
pip show requests

# Check environment for conflicts
pip check

Resolution Controls

# Only consider packages uploaded before a given date (pip 26.0+)
pip install --uploaded-prior-to 2025-01-01T00:00:00Z requests

# Exclude pre-releases for a specific package (pip 26.0+)
pip install --only-final fastapi

# Constrain build-time dependencies independently of runtime (pip 26.0+)
pip install --build-constraint build-constraints.txt -r requirements.txt

Limitations

pip has limitations to consider:

Lockfile support is experimental, and pip lock does not yet cover environment markers or multi-platform resolution
Does not manage Python interpreters or virtual environments
Slower package operations than uv, which resolves and installs in parallel

Learn More

Last updated on April 19, 2026

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