Web Tools
Dockerfile Linter
Lint Dockerfiles for common issues and best practices with 14 rules covering errors, warnings, and suggestions. Runs entirely in your browser — your data never leaves your machine.
docker dockerfile linter devops containers
Published May 31, 2026
All interactive tools run entirely in your browser. Your data never leaves your device.
How It Works
Paste a Dockerfile and get instant feedback on common issues, anti-patterns, and best practices. The linter checks 14 rules covering security, performance, and maintainability concerns. Each issue includes the rule ID, severity, line number, and a suggestion for fixing it.
Features
- 14 lint rules: covering errors, warnings, and info-level suggestions
- Error detection: missing FROM, invalid EXPOSE ports
- Best practices: avoid
latesttag, combine RUN instructions, use COPY over ADD - Security checks: sudo usage, StrictHostKeyChecking implications
- Deprecation warnings: MAINTAINER instruction, relative WORKDIR paths
- Parsed instructions table: see all Dockerfile instructions with line numbers
- Severity badges: color-coded error/warning/info counts at a glance
- 5 examples: good Dockerfile, bad practices, missing FROM, multi-stage, minimal Alpine
- Private: runs entirely in the browser — your data never leaves your machine
Use Cases
- Reviewing Dockerfiles before committing to CI/CD
- Learning Docker best practices and common pitfalls
- Quick validation of Dockerfile syntax
- Teaching Docker containerization fundamentals