RealDiff - Runtime behavior diffing for pull requests

Show HN: RealDiff – runtime behavior diffing for pull requests (six languages)

RealDiff is a developer tool that detects runtime behavior changes in pull requests, going beyond what static source diffs reveal. It builds two Git revisions, runs tests to observe behavior, and reports the first changed behavior in each call tree—even in files untouched by the PR. Supporting six languages (.NET, Java, Node, Go, Rust, Python), RealDiff integrates with CI systems like GitHub Actions and Azure DevOps, posting findings as PR comments. It helps catch subtle regressions, such as a stable sort altering pricing logic, that ordinary code review misses. With a unified CLI and containerized setup, RealDiff is easy to adopt in existing workflows.