Dockerfile Linter
Check Dockerfiles with basic syntax and best-practice heuristics
Last updated: October 14, 2026
About Dockerfile Linting
- Checks for syntax errors and invalid instructions
- Detects security issues like running as root or using latest tags
- Provides optimization tips for layer caching and image size
- Validates Dockerfile best practices
- Highlights issues with severity levels (Error, Warning, Info)
- Real-time linting as you type
Result actions
Copy or download the tool output, or share a link to Dockerfile Linter.
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Run a quick Dockerfile heuristic check
Paste or type a Dockerfile to see selected line-level hints. The checker looks for recognizable instruction lines and a limited set of patterns, including FROM and :latest, separate RUN commands, apt-get install options and cleanup, numeric EXPOSE ports, absolute-looking WORKDIR paths, ADD wildcards, root USER, repeated CMD or ENTRYPOINT, shell-form CMD, and risky rm -rf text.
These checks use simple string and regular-expression rules. They do not implement the full Dockerfile grammar, validate every instruction, inspect base image contents, find secrets, or perform a vulnerability scan. A “no issues” result is not proof that a Dockerfile is correct or secure. Use Docker and a dedicated linter or scanner for production review.
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