GitHub Actions costs are leaking, and most teams don't notice until it's too late

Two years ago I was working on a connected vehicles platform running 40+ microservices on Kubernetes. CI was healthy, tests were passing, and nobody was paying attention to the GitHub Actions bill until it hit $4,200 in a single month. The culprit was a matrix build that someone had extended to cover six Node versions. Nobody noticed because the cost didn't show up anywhere obvious. It wasn't flagged in any alert. The engineers who added the matrix jobs weren't thinking about cost. By the time finance asked the question, the pattern had been running for three months. I started looking for a tool that could give us per-workflow cost visibility. Something that would let us answer "which workflows cost the most" and "did this PR make CI more expensive." I didn't find anything that fit, so I built CICosts. What it does CICosts installs as a GitHub App and receives a webhook event every time a workflow run completes. It multiplies the runner minutes by GitHub's published pricing for that ru