kj84park / semgrep

Lightweight static analysis for many languages. Find bug variants with patterns that look like source code.

Lightweight static analysis for many languages.
Find bugs and enforce code standards.

Semgrep is a fast, open-source, static analysis tool for finding bugs and enforcing code standards at editor, commit, and CI time. Get started →.

Semgrep analyzes code locally on your computer or in your build environment: code is never uploaded.

Its rules look like the code you already write; no abstract syntax trees, regex wrestling, or painful DSLs. Here's a quick rule for finding Python print() statements, run it online in Semgrep's Playground by clicking the image:

The Semgrep ecosystem includes:

• Semgrep - The open-source command line tool at the heart of everything (this project).
• Semgrep Playground - An online interactive tool for writing and sharing rules.
• Semgrep Registry - 2,000+ community-driven rules covering security, correctness, and performance bugs.
• Semgrep App - Deploy, manage, and monitor Semgrep at scale with free and paid tiers. Integrates with CI providers such as GitHub, GitLab, CircleCI, and more.

Join 100,000 other developers and security engineers already using Semgrep at companies like Chef, Dropbox, Figma, HashiCorp, Snowflake, and Trail of Bits. Also check out tools powered by Semgrep!

Semgrep is developed and commercially supported by r2c, a software security company.

Language support

General availability

C# · Go · Java · JavaScript · JSX · JSON · PHP · Python · Ruby · Scala · TypeScript · TSX

Beta & experimental

See supported languages for the complete list.

Getting started

To install Semgrep use Homebrew or pip, or run without installation via Docker:

# For macOS
$ brew install semgrep

# For Ubuntu/WSL/Linux/macOS
$ python3 -m pip install semgrep

# To try Semgrep without installation run via Docker
$ docker run --rm -v "${PWD}:/src" returntocorp/semgrep

Once installed, Semgrep can run with single rules or entire rulesets. Visit Docs > Running rules to learn more or try the following:

# Check for Python == where the left and right hand sides are the same (often a bug)
$ semgrep -e '$X == $X' --lang=py path/to/src

# Fetch rules automatically by setting the `--config auto` flag.
# This will fetch rules relevant to your project from Semgrep Registry.
# The name of your project will be sent to Semgrep Registry as an identifier
# to make selecting relevant rules fast next time;
# source code will not be uploaded.
$ semgrep --config auto

Visit the full documentation to learn more.

Rule examples

Visit Docs > Rule examples for use cases and ideas.

Use case	Semgrep rule
Ban dangerous APIs	Prevent use of exec
Search routes and authentication	Extract Spring routes
Enforce the use secure defaults	Securely set Flask cookies
Tainted data flowing into sinks	ExpressJS dataflow into sandbox.run
Enforce project best-practices	Use assertEqual for == checks, Always check subprocess calls
Codify project-specific knowledge	Verify transactions before making them
Audit security hotspots	Finding XSS in Apache Airflow, Hardcoded credentials
Audit configuration files	Find S3 ARN uses
Migrate from deprecated APIs	DES is deprecated, Deprecated Flask APIs, Deprecated Bokeh APIs
Apply automatic fixes	Use listenAndServeTLS

Extensions

Visit Docs > Extensions to learn about Semgrep in your editor or pre-commit. When integrated into CI and configured to scan pull requests, Semgrep will only report issues introduced by that pull request; this lets you start using Semgrep without fixing or ignoring pre-existing issues!

Documentation

Browse the full Semgrep documentation on the website. If you’re new to Semgrep, check out Docs > Getting started or the interactive tutorial.

Metrics

Using remote configuration from the Registry (like --config=p/ci) reports pseudonymous rule metrics to semgrep.dev.

Using configs from local files (like --config=xyz.yml) does not enable metrics.

To disable Registry rule metrics, use --metrics=off.

PRIVACY.md describes the principles that guide data-collection decisions and the breakdown of the data that are and are not collected when the metrics are enabled.

More

• Frequently asked questions (FAQs)
• Contributing
• Build instructions for developers
• Ask questions in the r2c Community Slack
• CLI reference and exit codes
• r2c YouTube channel with Semgrep presentation videos
• License (LGPL-2.1)

Upgrading

To upgrade, run the command below associated with how you installed Semgrep:

# Using Homebrew
$ brew upgrade semgrep

# Using pip
$ python3 -m pip install --upgrade semgrep

# Using Docker
$ docker pull returntocorp/semgrep:latest