Docker Toolkit
Validate, lint, format, visualize, merge, and resolve Docker Compose files, and lint Dockerfiles — seven tools covering the whole Docker workflow. All run entirely in your browser.
How these fit together
Docker Compose Validator catches the mistakes that only normally surface at docker compose up — undefined services, invalid ports, undeclared volumes/networks — and Dockerfile Linter does the same for the image build itself: unpinned tags, missing USER, and other best-practice gaps. Docker Compose Formatter cleans up indentation while preserving comments, and Docker Compose Visualizer turns the file into a diagram of service start order, networks, and volumes — the fastest way to actually see how a multi-service stack fits together instead of tracing YAML by eye. Running more than one compose file together (a base plus an override, or several -f flags)? Docker Compose Merge Visualizer shows the fully merged result and exactly which file set each field. That merged (or single) file still has ${VAR} placeholders and shorthand fields Compose expands silently at runtime — Compose Config Inspector resolves the variables against a .env file and shell overrides and expands ports/volumes/environment/build into the long form Compose actually runs against. Once containers are actually running, Docker Network Inspector reads docker network inspect output and explains each network in plain English — including why containers on the default bridge can't find each other by name.
Docker Compose Validator
Check a docker-compose.yml for undefined services, bad ports, and undeclared volumes/networks.
Dockerfile Linter
Check a Dockerfile for typos, unpinned tags, and common build-cache mistakes.
Docker Compose Formatter
Clean up inconsistent indentation in a docker-compose.yml, comments preserved.
Docker Compose Visualizer
See a docker-compose.yml's services, networks, volumes, and start order at a glance.
Docker Compose Merge Visualizer
See exactly what -f base.yml -f override.yml produces, and which file set each field.
Compose Config Inspector
Resolve ${VAR} interpolation and expand shorthand fields, like docker compose config.
Docker Network Inspector
Paste `docker network inspect` output and see what it means — driver, subnets, attached containers, and why name resolution isn't working.
Guides
Learn more
- Docker Best Practices
- Understanding Docker Networks
- Common Docker Compose Errors
- How to Fix "invalid compose project" in Docker Compose
- Docker Bridge vs Host vs Overlay Networks
- Common Docker Compose Networking Errors
- How Docker DNS Resolution Works
- Docker Compose Environment Variables Explained
- How Docker Compose Overrides Work
- Docker Compose Volumes Explained
- Docker Layer Caching Explained