Bulk Sender Lint - the Gmail, Yahoo and Outlook.com rules, checked in your mailer code

21 dated checks over SPF, DKIM, DMARC, RFC 8058 one-click unsubscribe and TLS, in VS Code and in the browser

Install

npx @readystack/bulk-sender-lint file

Node 18+. The same 21 rules as the VS Code extension, from a terminal or CI.

Free

• Check the file you have open - all 21 checks, every finding with the clause it comes from, the date it took effect and the line
• --rules lists every rule

With a licence ($29 once)

• Sweep every matching file in the workspace and write a dated evidence report you keep, for a deliverability review or a client handover

@readystack/bulk-sender-lint --dir ./templates --report html --out report.html

A deliverability consultant bills $150 to $250 an hour

Use from an AI agent (MCP)

Claude Code · Cursor · Windsurf · any MCP client - add to your MCP config:

{ "mcpServers": { "bulk-sender-lint": { "command": "npx", "args": ["-y", "@readystack/bulk-sender-lint", "--mcp"] } } }

Tools: check_text and check_file (free) · check_dir (licence). The agent gets every finding with the line number.

Use in CI

- name: Bulk Sender Lint - the Gmail, Yahoo and Outlook.com rules, checked in your mailer code
  run: npx -y @readystack/bulk-sender-lint --dir . --ci

(container: docker run --rm -v "$PWD:/work" getreadystack/bulk-sender-lint --dir /work --ci)

The folder sweep, reports and CI mode need one licence — one payment, no subscription. Set READYSTACK_LICENSE=<key> or run --license <key> once.

Get a licence