GitLab CI Caching Didn’t Speed Up My Pipeline — Here’s Why

The author tested whether GitLab CI dependency caching actually speeds up pipelines using a small Python project with heavy dependencies. The result showed almost no improvement — and sometimes slightly slower runs — because fast mirrors, prebuilt wheels, and cache overhead (archiving, uploading, extracting) offset the benefits. Caching still has value for reducing traffic and improving resilience, but its performance impact depends on dependency size, network conditions, and runner setup.