Paste a Dockerfile to catch common mistakes missing tags, inefficient layer ordering, running as root, and more.
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Paste a Dockerfile to catch common mistakes missing tags, inefficient layer ordering, running as root, and more. Common questions — like does this replace validating against my actual cluster/ci — are answered in the FAQ below.
Add your input to the workspace above, review the result, then copy or download it when it's ready. No account or installation is required.
Dockerfile Linter runs in your browser, so the information you enter stays on your device instead of being uploaded to a server.
A few worked examples so you know what to expect before you paste in your own input.
Input
FROM node RUN apt-get update && apt-get install curl CMD npm start
Output
⚠ No explicit tag on FROM (defaults to :latest) ⚠ No USER instruction — runs as root ℹ CMD is in shell form, not exec form
Input
FROM node:20-alpine ENV API_SECRET=abc123 CMD ["node", "index.js"]
Output
⛔ Possible secret baked into the image via ENV (API_SECRET) — use build secrets or runtime env vars instead
Input
FROM node:20-alpine USER node HEALTHCHECK CMD curl -f http://localhost/ || exit 1 CMD ["node", "index.js"]
Output
No common issues found.
Catch Dockerfile smells, scaffold Helm values.yaml, and turn .env files into Compose environment blocks — before the cluster tells you what you missed.
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