MailWiz

An email verification devtool powered by the Mailboxlayer API.

Paste a single address, a comma-separated list, or drop in a CSV — get back one table with syntax validation, MX records, live SMTP check, catch-all detection, role/disposable/free flags, and a 0–1 deliverability score. Results export back out as CSV.

Shares its design system with IPWiz.

Setup

cp .env.example .env.local   # then paste your key
npm install
npm run dev

Get a free access key (100 requests/mo) at mailboxlayer.com.

How it works

• app/api/verify/route.ts — POST { emails: string[] }. The key stays server-side and never reaches the browser. Mailboxlayer's /bulk_check is a Pro-plan endpoint, so this fans out single /check calls through a 5-wide concurrency pool instead.
• app/lib/mailbox.ts — response types, email extraction, de-duplication, and the verdict() rollup that turns raw flags into deliverable / risky / undeliverable.
• app/components/ — VerifyPanel (textarea + CSV drop zone), ResultsTable (filters + CSV export), Header, ThemeToggle.

Notes on quotas

Every address costs one API credit, so requests are capped at MAX_BATCH (100) per call and duplicates are dropped before anything is sent. Adjust both in app/lib/mailbox.ts.