🔥 droast

Dockerfile linter with personality — 68 rules, zero servers, 100% client-side
Instant — runs in WebAssembly, no server round-trip 🔒 Private — your Dockerfile never leaves the browser 📋 68 rules — secrets, CVEs, bloat, misconfigs & more 🔌 GitHub Action — plug-and-play CI integration
Dockerfile
Results
📋

Paste a Dockerfile and click Roast it!

Free online Dockerfile linter

droast is a Dockerfile checker that runs entirely in your browser via WebAssembly — no server, no sign-up, no upload. Paste any Dockerfile and get instant lint results.

68 rules cover security misconfigurations, hardcoded secrets, outdated base images, layer bloat, missing health checks, and common anti-patterns. Each finding comes with a plain-English explanation and a snarky roast for good measure.

What it checks

The linter catches things like FROM :latest pins, exposed passwords in ENV, running as root, apt-get without pinned versions, COPY vs ADD misuse, and untrusted registries.

It maps rules to hadolint's DL-series IDs where applicable, so results are familiar if you already use hadolint in CI.

Plug into your CI pipeline

Beyond the browser tool, droast ships as a single binary and a ready-made GitHub Action. Add Dockerfile validation to any pull request in two lines of YAML — no Docker-in-Docker required.

Install via Homebrew on macOS and Linux:
brew tap immanuwell/droast git@github.com:immanuwell/homebrew-droast.git
brew install immanuwell/droast/droast