CLI

The @emailens/cli package runs the same @emailens/engine logic locally. No account is required for analyze, preview, audit, or lint. Optional hosted screenshots and share links use the Preview API with an API key.

Input can be HTML, MJML, Maizzle, or React Email (JSX). Format is inferred from the file extension unless you pass --format.

Install

npm install -g @emailens/cli

Or run without installing:

npx @emailens/cli analyze ./emails/welcome.html

Requires Node.js 18+.

Framework sources need extra packages

HTML works out of the box. Compiling other formats uses packages you install yourself, so the CLI stays small:

React Email files run in a sandbox that only allows imports from react and @react-email/components. For a project with shared components, lint the exported HTML instead. See React Email.

Commands

Run emailens --help or emailens <command> --help for the full flag list on your installed version.

analyze

Quick compatibility pass with a score table and grouped warnings.

emailens analyze email.html
emailens analyze email.html --clients gmail-web,outlook-windows
emailens analyze email.html --json
cat email.html | emailens analyze -- -

To read from stdin, pass -- -. A bare - is not accepted.

Source positions (line/column in warnings) are reported for HTML input only. Compiled MJML, JSX, and Maizzle omit positions because line numbers would refer to generated output, not your source file.

lint

Use this in pre-commit hooks and CI. Exit codes:

• 0, no errors (and no --fail-on-warning / --max-warnings failure)
• 1, at least one error-severity issue
• 2, warnings only when --fail-on-warning is set, or --max-warnings exceeded

emailens lint 'emails/*.html'
emailens lint email.html --json
emailens lint email.html --fail-on-warning
emailens lint email.html --skip spam,links

lint takes one path or one single-level glob. Quote the glob so the CLI expands it, not your shell: any argument after the first is ignored. ** and {a,b} are not supported. To lint a tree, run it once per file:

find emails -name '*.html' -print0 | xargs -0 -n1 emailens lint

See Project config for .emailensrc / package.json emailens rules shared with the VS Code extension.

GitHub Actions

For a dedicated Action with PR annotations, see GitHub Action.

Local lint in a workflow:

- run: find emails -name '*.html' -print0 | xargs -0 -n1 npx -y @emailens/cli lint --fail-on-warning

preview

Runs transforms, analysis, and dark mode preview. --screenshots renders locally and needs a Browserless instance: set BROWSERLESS_URL and install playwright-core. For hosted screenshots with no setup, use the MCP server or the API.

emailens preview email.html
emailens preview email.html --dark-mode
emailens preview email.html --json

audit

Single-file comprehensive report (compatibility plus content and deliverability-style checks). Use lint when you need CI exit codes across many files.

emailens audit email.html
emailens audit email.html --json --skip spam

Shared flags

Most file commands accept:

More detail

Command tables, .emailensrc precedence, and CI examples are also documented in the CLI README on GitHub.