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Documentation Index

Fetch the complete documentation index at: https://docs.semgrep.dev/llms.txt

Use this file to discover all available pages before exploring further.

  • Automate code review comments.
  • Identify secure coding violations.
  • Scan configuration files.
See more use cases in Rule ideas.

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Get started

For an introduction to writing Semgrep rules, use the interactive, example-based Semgrep rule tutorial. You can write rules in your terminal and run them with the Semgrep command line tool, or you can write and test using the Semgrep Editor. For example, the following sample rule detects the use of is when comparing Python strings. is checks reference equality, not value equality, and can exhibit nondeterministic behavior.

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Next steps

The following articles guide you through rule-writing basics and act as references:
  • Pattern syntax describes what Semgrep patterns can do in detail and provides sample use cases.
  • Rule syntax describes Semgrep YAML rule files, which can have multiple patterns, detailed output messages, and Rule-defined fixes. The syntax allows the composition of individual patterns with Boolean operators.
  • Contributing rules gives you an overview of how you can contribute to Semgrep Registry rules. This document also provides information about tests and metadata fields that you can use for your rules.
Need rule ideas? See Rule ideas for everyday use cases and prompts to help you start writing rules from scratch.