Dockerfile Linter
Lint Dockerfiles for common issues, best practices, and security concerns. Get actionable suggestions to improve your container builds.
Frequently Asked Questions
What does the Dockerfile Linter check?
It checks for common issues like using :latest tags, multiple consecutive RUN commands that should be combined, using ADD instead of COPY, missing WORKDIR, missing USER instruction, and more.
Is this a replacement for Hadolint?
No — this is a lightweight browser-based linter that catches the most common Dockerfile anti-patterns. For comprehensive CI/CD linting, use Hadolint or similar tools.
What severity levels are used?
Issues are categorized as Error (likely bugs or security concerns), Warning (best-practice violations), and Info (suggestions for improvement).
Why should I avoid the :latest tag?
The :latest tag is mutable and can change unexpectedly, leading to unreproducible builds. Always pin to a specific version or digest for deterministic builds.
Why combine RUN commands?
Each RUN instruction creates a new image layer. Combining related commands with && reduces the number of layers and final image size, especially for apt-get install chains.