pip install --only-binary: Force Wheels, Skip Builds

Refuse source builds so installs stay fast and don’t need a compiler.

The --only-binary flag makes pip install from wheels only, never building from source. It avoids slow C-extension builds and missing-compiler failures in CI.

What it does

Restricts pip to binary distributions (wheels) for the named packages, or all packages with :all:. If no compatible wheel exists, pip errors instead of building from sdist.

Common usage

pip install --only-binary=:all: -r requirements.txt
pip install --only-binary=numpy,scipy numpy scipy
# Opposite: force a source build
pip install --no-binary=:all: somepkg

Common CI error: no wheel available

If a package has no wheel for the runner’s platform/Python, --only-binary=:all: fails fast. Either drop the restriction for that package or use a platform with published wheels.

# Failure:
# ERROR: Could not find a version that satisfies the
# requirement somepkg (from versions: ...) [no wheels]

# Fix: allow source for just that package
pip install --only-binary=:all: --no-binary=somepkg -r requirements.txt

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