requirements.txt

Learn dependency management with requirements.txt.

requirements.txt

requirements.txt lists the dependencies of a project, one per line. The pip install -r requirements.txt command installs every package in the list. It is used as an alternative to pyproject.toml in production deployments.

requests>=2.28
httpx==0.24

Each line holds a package and an optional version specifier. The pip freeze > requirements.txt command produces this file by freezing the exact versions of installed packages.

Version specifiers

Dependency lines use version specifiers: >= means at least, == means exact, < means less than, ~= means compatible release.

requests>=2.28    # at least 2.28
httpx==0.24      # exactly 0.24
rich<13         # less than 13

In production, locking with == gives predictability. In development, >= is more flexible but may surprise you on major version bumps.

Exercise Count the lines in requirements.txt

Assign the following content to a string variable named requirements:

requests>=2.28
httpx==0.24

Then list the lines with deps = [line for line in requirements.strip().split("\n") if line.strip()]. Print the line count with print(len(deps)) and the first line with print(deps[0]).

Show example solution

requirements = "requests>=2.28\nhttpx==0.24\n"

deps = [line for line in requirements.strip().split("\n") if line.strip()]
print(len(deps))
print(deps[0])

Test yourself

What does pip freeze > requirements.txt do?
- Builds a wheel
- Removes packages
- Creates a virtual environment
- Freezes installed versions
Show answer

Freezes installed versions — pip freeze writes the exact versions of installed packages to the file.
Complete the >= specifier
```
requests____2.28
```
Show answer
```
requests>=2.28
```
Match the version specifiers

>=

At least
==

Exact
<

Less than
~=

Compatible

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