Make your Dockerfile proud of itself.

Dockadvisor is a free online Dockerfile analyzer that helps you write better, more efficient Docker configurations. Paste your Dockerfile to get instant feedback on best practices, issues, and optimization opportunities.

Why Dockerfile Optimization Matters

This is not just about best practices; a well-optimized Dockerfile directly impacts your development workflow, security posture, and production costs. Here’s why it matters:

Faster Build Times

Proper layer caching and instruction ordering can bring build times down from minutes to seconds. Multi-stage builds remove all the extra dependencies from the final images, making them leaner and faster.

Smaller Image Sizes

Optimizing Dockerfiles can lead to image sizes being reduced by 50-90%. Smaller images offer faster deployments, lower storage costs, and reduced attack surface for security vulnerabilities.

Enhanced Security

Security Exposed secret detection, running as non-root users, and avoiding deprecated features all help avert security breaches. One exposed API key or password is enough to compromise an entire infrastructure.

Lower Costs

Lower Costs Efficient Docker images reduce bandwidth costs, storage fees, and compute resources. This savings compounds in production where hundreds or thousands of container instances may be used.

Frequently Asked Questions

What does Dockadvisor check in my Dockerfile?

Dockadvisor implements over 50 validation rules across 18 different Dockerfile instructions. It checks syntax errors (JSON arrays, key=value formats, port ranges), security issues (exposed secrets and credentials), best practices (deprecated features, proper signal handling), and style consistency (casing, absolute paths). It also performs cross-instruction analysis to detect issues in multi-stage builds, variable scope problems, and duplicate declarations.

What security vulnerabilities can Dockadvisor detect?

Dockadvisor actively scans for exposed sensitive data in ARG and ENV instructions by detecting keywords like "password," "secret," "apikey," "token," and similar patterns. It validates RUN instruction mount types (bind, cache, tmpfs, secret, ssh) and checks network/security flags. It also warns against security anti-patterns and helps prevent credential leakage in your Docker images.

Does Dockadvisor work with multi-stage builds?

Yes! Dockadvisor has sophisticated multi-stage build analysis. It detects duplicate stage names, ensures ARG variables in FROM instructions are properly declared in global scope with default values, tracks variable scope throughout each build stage, and warns when multiple CMD, ENTRYPOINT, or HEALTHCHECK instructions appear (only the last one takes effect).

Is my Dockerfile sent to your servers?

No. Dockadvisor runs entirely in your browser using WebAssembly. Your Dockerfile never leaves your device, ensuring complete privacy and security. All analysis happens client-side, making it safe to analyze proprietary and sensitive Dockerfiles.

Is Dockadvisor free to use?

Yes, Dockadvisor is completely free for both personal and commercial use. No signup, no payment, no limits on usage. We built this tool to help the Docker community write better, more secure Dockerfiles.

Which Dockerfile instructions does Dockadvisor analyze?

Dockadvisor analyzes all 18 major Dockerfile instructions including FROM, RUN, CMD, ENTRYPOINT, COPY, ADD, ENV, ARG, WORKDIR, EXPOSE, USER, LABEL, HEALTHCHECK, SHELL, STOPSIGNAL, ONBUILD, VOLUME, and the deprecated MAINTAINER. It validates syntax, flags, and best practices for each instruction type.

Dockadvisor uses open source software including moby/buildkit licensed under the Apache License 2.0.