Dockerfile Layer Analyzer

Each instruction in a Dockerfile creates a new layer. Layers are cached and reused across builds, making them a critical factor in build performance and image size. Too many layers or poorly ordered instructions can lead to slow builds, large images, and cache invalidation issues.

This analyzer checks for common issues:

• Multi-stage builds — Separate build dependencies from runtime artifacts
• Base image size — Alpine-based images vs full Debian-based
• Layer ordering — Instructions that invalidate the cache frequently
• Dependency management — npm/pip install without cache flags
• COPY strategy — Copying dependency files separately from source code
• .dockerignore — Excluding unnecessary files from build context

1. Paste your Dockerfile — Copy the entire content of your Dockerfile into the text area. You can use the "Example" link to load a sample Dockerfile that demonstrates common issues.
2. Click "Analyze" — The tool parses every instruction and computes the number of layers, build stages, base image, and estimated image size.
3. Review the Overview — Check the summary cards for total layers, build stages, base image, and estimated size.
4. Read Issues & Recommendations — Each detected problem is listed with a concrete fix, such as reordering instructions or switching to a multi-stage build.
5. Apply Optimization Suggestions — Follow the tailored suggestions to shrink the image and speed up rebuilds. Use the Clear button to start over.