Foundation Machines vs Semgrep.
Semgrep is a CLI-first SAST with a custom rule engine. Sebastion AI is a PR-native AI security reviewer with no rules to write. Where each one wins.
Semgrep is one of the most respected SAST tools — its open-source engine is fast, the custom rule language is approachable, and the community ruleset is huge. The trade-off is that to get high-quality results on your codebase you usually end up writing or tuning rules. Sebastion AI is AI-native and rule-free: it reads the PR diff in context and posts security review comments without rule-authoring. Many teams run both — Semgrep for enforceable policy, Sebastion for catching the things rules don't describe.
Visit Semgrep to evaluate them directly. We try to keep this comparison accurate; let us know if anything is wrong.
What you get from each.
Choose Semgrep when
You need enforceable, deterministic rules — compliance owns a list of patterns that must never appear, or you have a security team that's happy to write and maintain a ruleset. Semgrep gives you full control of the signal.
Choose Sebastion AI when
You don't want to write rules. Sebastion reviews the diff in context and posts findings as PR review comments with explanations and fixes. Free for public repos, $19/dev/mo for private — designed to run alongside Semgrep, not replace it.
Try Foundation Machines on your next PR.
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