conda-lock vs virtualenv

conda-lock is a lightweight library for producing reproducible lockfiles for conda environments. It solves dependencies separately for each target platform, allowing installations from generated lockfiles to avoid running the conda solver. Inputs can come from environment.yml, conda-build meta.yaml, or pyproject.toml dependency specifications. Its default unified lockfile covers multiple platforms and can be rendered into other lockfile formats. Documented target examples include Linux, macOS, Windows, and additional Linux architectures. The project describes use alongside conda, mamba, pip, Docker, and pixi, and provides installation routes through pip, conda, and mamba; pipx or condax are recommended for isolated installation. Mixed conda-and-pip locking is experimental. Channel access supports token or basic authentication, with environment-variable substitution for credentials. The unified lockfile can omit raw credential-bearing channel URLs when it matches credential portions to environment variables, although rendered explicit lockfiles may contain substituted variables. Private pip repository support is limited to legacy PyPI repositories using basic authentication. The software is MIT-licensed and free.

virtualenv has no write-up on Specifiction yet; its figures are above.