About Semgrep

Semgrep is an open-source static application security testing engine built around a lightweight pattern-matching approach, letting security teams write custom rules in a syntax close to the target programming language rather than learning a separate rules DSL. This makes it especially popular with security teams enforcing organization-specific policies across many repositories. It is free to self-host with unlimited use for the open-source engine, and free for hosted Teams plans under 10 developers, with paid tiers running roughly $30-40 per contributor per month for Semgrep Code or Supply Chain, plus a separate $15/contributor/month Secrets add-on. Independent benchmarks show Semgrep leads specifically on security-finding accuracy, with its AI-assisted triage agreeing with human security researchers on true positives about 96% of the time, though it explicitly does not cover code quality metrics, complexity analysis, or duplication detection the way SonarQube does.

Key features

Custom rule authoring

Write security rules in syntax close to the target language, not a separate DSL

AI-assisted triage

Automatically handles roughly 60% of security triage, 96% agreement with human researchers

Free open-source engine

Self-hostable with unlimited use at no cost

OWASP Top 10 coverage

Built-in rules covering standard security benchmarks out of the box

Pros and cons

✓ Pros

Strongest custom security rule authoring of any tool in the category

Free, unlimited self-hosted engine with no vendor lock-in

AI triage assistant genuinely reduces false-positive fatigue for security teams

Free hosted tier for teams under 10 developers lowers the barrier to entry

✗ Cons

Narrowly security-focused: no code quality metrics, complexity analysis, or duplication detection

Not AI-native for general code review the way CodeRabbit or Greptile are

Requires security expertise to get full value from custom rule authoring

Paid tiers stack per product (Code, Supply Chain, Secrets), adding cost for full coverage

Best for

Security teams needing custom, organization-specific SAST rulesTeams wanting a free, self-hostable security scanning engineOrganizations already running a separate AI code review tool wanting a security layerCompliance-driven teams needing OWASP Top 10 and SANS Top 25 coverage

Why this score

Leading open-source SAST engine for custom security rules, free for teams under 10 developers