The drag-and-drop email builder that helps you ship with confidence.

An HTML email builder lets you design responsive email templates visually — dragging in text, images, buttons and columns — and then export clean HTML you can send through any email service provider. The MailViewr Email Builder is a drag-and-drop HTML email builder with built-in preview and validation.

MJML is a markup language that abstracts the complexity of responsive HTML email. The MailViewr Email Builder uses MJML under the hood so your emails render reliably across clients, and you can edit MJML directly or export it alongside HTML.

Yes. The Email Builder exports clean, standards-based, table-friendly HTML with one click. The output works with Gmail, Outlook, Apple Mail and any ESP such as Mailchimp, Klaviyo, SendGrid or HubSpot.

Yes. Because the Email Builder is built on MJML, it generates bulletproof HTML that renders reliably in Outlook — including the desktop versions that use Microsoft Word's rendering engine. You can also preview and compatibility-test Outlook before sending.

Yes. The Email Builder includes built-in dark-mode preview so you can catch inverted colors, washed-out logos and contrast issues before your subscribers ever see them.

Yes. The Email Builder runs your email through SpamAssassin — the industry-standard open-source spam engine — and returns your score, the pass/fail threshold and a per-rule breakdown so you can fix issues before you send.

The Email Builder's accessibility checker scans your email for missing alt text, low color contrast and structural issues that make emails hard to read for people using assistive technology — and flags them so you can fix them in the editor.

Yes. The Email Builder exports standard HTML that you can paste or import into Mailchimp, Klaviyo, HubSpot, SendGrid, Brevo, Constant Contact and any other email platform.

Absolutely. The Email Builder isn't a black box — developers can work in MJML, export clean HTML, import existing templates, and rely on version history and snapshots for real template version control.

Yes. You can import existing MJML or HTML into the Email Builder and keep editing visually or in code — so you don't have to rebuild templates from scratch.

Yes. The Email Builder works for newsletters, promotional campaigns, welcome and onboarding emails, transactional messages, event invitations and more — start from a template or a blank canvas.

Yes. Generate a shareable preview link so teammates or clients can review the email in the browser and sign off before it goes out — no account needed to view.

Yes. Send a real test email to your own inbox straight from the Email Builder to see exactly how it looks in your actual email client before launching.

No signup is required to try it — open the Email Builder and start building right away. Creating an account unlocks the full Email Readiness suite (spam, QA, and compatibility checks) before you send.

Litmus offers real-device screenshot testing across a much wider client matrix, but it is now enterprise-only — no self-serve signup and no published plan pricing. MailViewr covers the highest-volume clients with a rendering engine instead of screenshots, publishes per-client accuracy figures, and adds a builder Litmus doesn't have. Litmus is the stronger pick for pixel-perfect QA across niche clients; MailViewr is the one you can start using today without a sales call.