Foundation Machines vs Greptile.
Greptile is an AI reviewer optimised for codebase-wide context in large monorepos. Sebastion AI is security-first and pre-merge. Where each one wins.
Greptile and Sebastion AI are both AI GitHub Apps that post PR review comments. Greptile's edge is its full-repo graph — it's the strongest tool we've seen for cross-file refactor breakage and call-site analysis in large monorepos. Sebastion AI is narrower: a security-only reviewer that flags exploitable bugs, tags them with severity and CWE id, and posts ready-to-apply fixes. Most teams running both treat Greptile as the generalist and Sebastion as the security specialist.
Visit Greptile to evaluate them directly. We try to keep this comparison accurate; let us know if anything is wrong.
What you get from each.
Choose Greptile when
You're working in a large monorepo where the hardest review problem is “did this change quietly break 12 call sites in unrelated services?” Greptile's codebase graph is purpose-built for that and it's the best-in-class option.
Choose Sebastion AI when
You want a reviewer whose first job is “catch security regressions before they merge.” Sebastion is faster to set up (no indexing), free for public repos and cheaper per seat. Designed to run alongside Greptile, not replace it.
Try Foundation Machines on your next PR.
Free for solo developers and OSS maintainers. Install Sebastion and review your next pull request in under a minute.
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