MJML vs PostBrix
MJML
mjml.ioPostBrix
postbrix.comSide by side
| Figure | MJML | PostBrix |
|---|---|---|
| Price from | Free | $9/mo |
| Free plan | Yes | Yes |
| Free trial | — | Yes |
| Open source | Yes | — |
| Web | Yes | Yes |
| Windows | Yes | — |
| macOS | Yes | — |
| Linux | Yes | — |
| API | Yes | Yes |
| Self-hosted | Yes | — |
| Plans published | 3 | 8 |
| Spec score · Email Design Software | 8.6 (#7) | 8.5 (#8) |
| Spec score · Email Template Software | 8.7 (#6) | 8.6 (#7) |
| API | The MJML REST API is free to use and renders MJML into responsive HTML. | The documented REST API uses https://api.postbrix.com/v1 with Bearer API-key authentication and endpoints for rendering templates, listing projects, fetching project AST data and health checks. |
| Documentation depth | Documentation covers component attributes, CLI options, Node usage, browser usage, JSON input, custom components, tooling and compatibility charts. | The documentation site reports 91 production guides across eight categories and covers API, JSON schema, rendering, integrations, testing and troubleshooting. |
| Integrations | The documented ecosystem includes Mailjet, Parcel, IntelliJ IDEA, Gradle, Neos CMS, and Easy-email. | Export guidance covers Mailchimp, SendGrid, Klaviyo, Brevo, HubSpot, Postmark, Customer.io, ActiveCampaign and Mailgun, plus Amazon SES compatibility on the homepage. |
| Responsive design | MJML is responsive by design on popular email clients, including Outlook. | PostBrix says its layouts are designed for mobile and desktop by default. |
| Responsive layouts | Columns automatically stack for mobile layouts and the framework targets major email clients including Outlook. | PostBrix automatically targets desktop and mobile email layouts and supports mobile stacking and per-block overrides. |
| Self-hosting | Because the compiler is open source and installable from npm, teams can run MJML locally or in their own build and CI systems. | The product pages describe browser delivery and hosted API rendering; no self-hosting package or deployment instructions are published. |
| Support | MJML invites users to contact [email protected] and participate through Slack and GitHub. | Support is offered through [email protected], and the careers page identifies the operating location as Madhya Pradesh, India. |
| What it does | MJML is a markup language and compiler that turns semantic email markup into responsive HTML using nested tables, inline CSS and client-specific workarounds. | PostBrix is a cloud email-design workspace for creating, storing, previewing, exporting and managing responsive templates and related assets. |
Plans
PostBrix
- FreeFree
- FreeFree
- Starter$9 a month
- Starter$9 a month
- Pro$29 a month
- Pro$29 a month
- EnterprisePriced on request
- Enterprise & AgencyPriced on request
In their own words
MJML
MJML is a markup language for building responsive email layouts. Its engine converts MJML into email HTML made with nested tables and inline CSS, with responsive behavior for popular email clients, including Outlook. Reusable, extensible components provide a starting point, and users can create their own components. MJML is open source under the MIT license and free to use. Its online editor supports writing and rendering MJML, and its free REST API renders markup into responsive HTML. The command-line interface can compile files, watch for changes, and save generated HTML to a chosen file. Local installation is available through npm on macOS, Linux, and Windows; plugins are available for Visual Studio Code and Sublime Text, alongside a desktop app. API accounts receive an Application ID and two API keys, with public and secret keys intended for browser and back-end use. Includes are ignored by default, and enabled include paths are restricted to approved roots. Once the HTML is rendered, users must send it through an email service provider or directly from a shell. The mj-button component is not fully clickable because of email-client support.
PostBrix
PostBrix is a browser-based email builder for producing responsive templates and organizing assets for campaigns. Its visual editor lets users arrange text, images, buttons, dividers, and columns without writing HTML. Layouts are designed for mobile and desktop, and saved headers, footers, and calls to action can be reused across projects. The product can help generate or refine email copy with AI, then export templates as MJML or fully inlined HTML for an existing workflow. PostBrix says its exported code works with services that accept HTML or MJML, including Mailchimp, HubSpot, SendGrid, Brevo, Postmark, Amazon SES, Klaviyo, Customer.io, ActiveCampaign, and Mailgun. The documentation also describes REST API rendering and key management, live previews, test emails, responsive checks, and rendering troubleshooting. A free plan and free trial are available; paid plans start at $9/mo. The free tier is limited to five monthly exports, five daily downloads, three daily test emails, and ten lifetime AI generations.